The average person has 5 million hairs. Hair grows all over your body except on your lips, palms, and the soles of your feet. It takes about a month for healthy hair to grow half an inch. Most hairs grow for up to six years and then fall out. New hairs grow in their place.

Hair helps keep you warm. It also protects your eyes, ears and nose from small particles in the air. Common problem with the hair and scalp include hair loss, infections, and flaking.

Hair

Hair is a keratinous filament growing out of the epidermis. It is primarily made of dead, keratinized cells. Strands of hair originate in an epidermal penetration of the dermis called the hair follicle. The hair shaft is the part of the hair not anchored to the follicle, and much of this is exposed at the skin’s surface. The rest of the hair, which is anchored in the follicle, lies below the surface of the skin and is referred to as the hair root. The hair root ends deep in the dermis at the hair bulb, and includes a layer of mitotically active basal cells called the hair matrix. The hair bulb surrounds the hair papilla, which is made of connective tissue and contains blood capillaries and nerve endings from the dermis (Figure 5.11).

Just as the basal layer of the epidermis forms the layers of epidermis that get pushed to the surface as the dead skin on the surface sheds, the basal cells of the hair bulb divide and push cells outward in the hair root and shaft as the hair grows. The medulla forms the central core of the hair, which is surrounded by the cortex, a layer of compressed, keratinized cells that is covered by an outer layer of very hard, keratinized cells known as the cuticle. These layers are depicted in a longitudinal cross-section of the hair follicle (image), although not all hair has a medullary layer. Hair texture (straight, curly) is determined by the shape and structure of the cortex, and to the extent that it is present, the medulla. The shape and structure of these layers are, in turn, determined by the shape of the hair follicle. Hair growth begins with the production of keratinocytes by the basal cells of the hair bulb. As new cells are deposited at the hair bulb, the hair shaft is pushed through the follicle toward the surface. Keratinization is completed as the cells are pushed to the skin surface to form the shaft of hair that is externally visible. The external hair is completely dead and composed entirely of keratin. For this reason, our hair does not have sensation. Furthermore, you can cut your hair or shave without damaging the hair structure because the cut is superficial. Most chemical hair removers also act superficially; however, electrolysis and yanking both attempt to destroy the hair bulb so hair cannot grow.

The wall of the hair follicle is made of three concentric layers of cells. The cells of the internal root sheath surround the root of the growing hair and extend just up to the hair shaft. They are derived from the basal cells of the hair matrix. The external root sheath, which is an extension of the epidermis, encloses the hair root. It is made of basal cells at the base of the hair root and tends to be more keratinous in the upper regions. The glassy membrane is a thick, clear connective tissue sheath covering the hair root, connecting it to the tissue of the dermis.

Hair serves a variety of functions, including protection, sensory input, thermoregulation, and communication. For example, hair on the head protects the skull from the sun. The hair in the nose and ears, and around the eyes (eyelashes) defends the body by trapping and excluding dust particles that may contain allergens and microbes. Hair of the eyebrows prevents sweat and other particles from dripping into and bothering the eyes. Hair also has a sensory function due to sensory innervation by a hair root plexus surrounding the base of each hair follicle. Hair is extremely sensitive to air movement or other disturbances in the environment, much more so than the skin surface. This feature is also useful for the detection of the presence of insects or other potentially damaging substances on the skin surface. Each hair root is connected to a smooth muscle called the arrector pili that contracts in response to nerve signals from the sympathetic nervous system, making the external hair shaft “stand up.” The primary purpose for this is to trap a layer of air to add insulation. This is visible in humans as goose bumps and even more obvious in animals, such as when a frightened cat raises its fur. Of course, this is much more obvious in organisms with a heavier coat than most humans, such as dogs and cats.

Hair Growth

Hair grows and is eventually shed and replaced by new hair. This occurs in three phases. The first is the anagen phase, during which cells divide rapidly at the root of the hair, pushing the hair shaft up and out. The length of this phase is measured in years, typically from 2 to 7 years. The catagen phase lasts only 2 to 3 weeks, and marks a transition from the hair follicle’s active growth. Finally, during the telogen phase, the hair follicle is at rest and no new growth occurs. At the end of this phase, which lasts about 2 to 4 months, another anagen phase begins. The basal cells in the hair matrix then produce a new hair follicle, which pushes the old hair out as the growth cycle repeats itself. Hair typically grows at the rate of 0.3 mm per day during the anagen phase. On average, 50 hairs are lost and replaced per day. Hair loss occurs if there is more hair shed than what is replaced and can happen due to hormonal or dietary changes. Hair loss can also result from the aging process, or the influence of hormones.

Hair Color

Similar to the skin, hair gets its color from the pigment melanin, produced by melanocytes in the hair papilla. Different hair color results from differences in the type of melanin, which is genetically determined. As a person ages, the melanin production decreases, and hair tends to lose its color and becomes gray and/or white.

Nails

The nail bed is a specialized structure of the epidermis that is found at the tips of our fingers and toes. The nail body is formed on the nail bed, and protects the tips of our fingers and toes as they are the farthest extremities and the parts of the body that experience the maximum mechanical stress (Figure 5.13). In addition, the nail body forms a back-support for picking up small objects with the fingers. The nail body is composed of densely packed dead keratinocytes. The epidermis in this part of the body has evolved a specialized structure upon which nails can form. The nail body forms at the nail root, which has a matrix of proliferating cells from the stratum basale that enables the nail to grow continuously. The lateral nail fold overlaps the nail on the sides, helping to anchor the nail body. The nail fold that meets the proximal end of the nail body forms the nail cuticle, also called the eponychium. The nail bed is rich in blood vessels, making it appear pink, except at the base, where a thick layer of epithelium over the nail matrix forms a crescent-shaped region called the lunula (the “little moon”). The area beneath the free edge of the nail, furthest from the cuticle, is called the hyponychium. It consists of a thickened layer of stratum corneum.

Figure 5.13 Nails The nail is an accessory structure of the integumentary system.

Sweat Glands

When the body becomes warm, sudoriferous glands produce sweat to cool the body. Sweat glands develop from epidermal projections into the dermis and are classified as merocrine glands; that is, the secretions are excreted by exocytosis through a duct without affecting the cells of the gland. There are two types of sweat glands, each secreting slightly different products.

An eccrine sweat gland is a type of gland that produces a hypotonic sweat for thermoregulation. These glands are found all over the skin’s surface, but are especially abundant on the palms of the hand, the soles of the feet, and the forehead (Figure 5.14). They are coiled glands lying deep in the dermis, with the duct rising up to a pore on the skin surface, where the sweat is released. This type of sweat, released by exocytosis, is hypotonic and composed mostly of water, with some salt, antibodies, traces of metabolic waste, and dermicidin, an antimicrobial peptide. Eccrine glands are a primary component of thermoregulation in humans and thus help to maintain homeostasis.

Figure 5.14 Eccrine Gland Eccrine glands are coiled glands in the dermis that release sweat that is mostly water.

An apocrine sweat gland is usually associated with hair follicles in densely hairy areas, such as armpits and genital regions. Apocrine sweat glands are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis, with the duct normally emptying into the hair follicle. In addition to water and salts, apocrine sweat includes organic compounds that make the sweat thicker and subject to bacterial decomposition and subsequent smell. The release of this sweat is under both nervous and hormonal control, and plays a role in the poorly understood human pheromone response. Most commercial antiperspirants use an aluminum-based compound as their primary active ingredient to stop sweat. When the antiperspirant enters the sweat gland duct, the aluminum-based compounds precipitate due to a change in pH and form a physical block in the duct, which prevents sweat from coming out of the pore.

Sebaceous Glands

A sebaceous gland is a type of oil gland that is found all over the body and helps to lubricate and waterproof the skin and hair. Most sebaceous glands are associated with hair follicles. They generate and excrete sebum, a mixture of lipids, onto the skin surface, thereby naturally lubricating the dry and dead layer of keratinized cells of the stratum corneum, keeping it pliable. The fatty acids of sebum also have antibacterial properties, and prevent water loss from the skin in low-humidity environments. The secretion of sebum is stimulated by hormones, many of which do not become active until puberty. Thus, sebaceous glands are relatively inactive during childhood.

Hair serves a variety of functions, including protection, sensory input, thermoregulation, and communication. For example, hair on the head protects the skull from the sun. The hair in the nose and ears, and around the eyes (eyelashes) defends the body by trapping and excluding dust particles that may contain allergens and microbes. Hair of the eyebrows prevents sweat and other particles from dripping into and bothering the eyes. Hair also has a sensory function due to sensory innervation by a hair root plexus surrounding the base of each hair follicle. Hair is extremely sensitive to air movement or other disturbances in the environment, much more so than the skin surface. This feature is also useful for the detection of the presence of insects or other potentially damaging substances on the skin surface. Each hair root is connected to a smooth muscle called the arrector pili that contracts in response to nerve signals from the sympathetic nervous system, making the external hair shaft “stand up.” The primary purpose for this is to trap a layer of air to add insulation. This is visible in humans as goose bumps and even more obvious in animals, such as when a frightened cat raises its fur. Of course, this is much more obvious in organisms with a heavier coat than most humans, such as dogs and cats.

Short, long, curly, straight, up, down. Hair options can seem endless! Not all of what makes your hair look good comes from the outside, though. Good nutrition, physical activity, staying away from the sun, and other healthy habits can help your hair shine!

Here are some other tips for hair care:

If your hair is oily: Try washing your hair every day. You may also want to try shampoos that are made for oily hair. And stop using hair products that have oil in them, like pomades.

If your hair is dry: You may want to use a moisturizing shampoo made for dry hair. Also use a cream rinse or conditioner. You could also try shampooing less often.

If you see white flakes in your hair or on your shoulders: You most likely have dandruff. Try a dandruff shampoo. If it doesn’t help, your doctor may prescribe something stronger.

If you want to dye your hair:

• If possible, you might consider having a professional do this for you.
• If you are dyeing your hair at home, it’s best to get someone’s help.
• Follow the directions in the package carefully, especially any warnings.
• Do a test before using dye on your hair. Rub a tiny bit of the dye on the inside of your elbow or behind your ear. Leave it there for two days. If you get a rash, don't use the dye on your hair.
• Wear gloves when you apply dye.
• Talk with your doctor if your skin or scalp swells or gets itchy after using any hair product. Even natural products, such as henna dye, can cause an allergic reaction.

If you want to straighten your hair:

• If possible, you might consider having a professional do this for you.
• You can use a relaxer product at home, but it can burn your scalp if you use it the wrong way.
• It’s best not to try using a relaxer product by yourself. Get help to make sure you’ve put it on evenly and you get it all out when you’re through.
• Make sure to follow any directions, and don’t leave the straightener on too long.
• Keep in mind that straightening your hair can damage it. Try not to straighten it too often. Some hairdressers say around once every two months is okay.

If you want to make your hair curly:

• If you can, you might consider having a professional do this for you.
• You can use a permanent wave, or “perm” at home, but it’s a good idea to get help.
• Make sure to follow any directions, and don’t leave it on too long.

If you use hairdryers, curling irons, flat irons, or similar products: Be careful not to overuse them. Dryers and other products that use heat can dry out or break your hair. It’s a good idea to take a few days off from time to time.

If you swim in a pool a lot: Protect your hair from chlorine by wearing a swim cap or rinsing out your hair right after swimming. Soaking your hair with regular water before you put on your swim cap can also help.

Pili annulati is a hair disorder. In pili annulati, affected hair has a pattern of light and dark banding. People with pili annulati maydescribe their hair as "striped" or as having silvery beads. Pili annulati typically involves 20-80% of scalp hair, however it can involvefacial and body hair as well. Affected hairsmay be more prone to breakage. Pili annulati can present in infancy,childhood, or later in life. It can be seen withthe naked eye, however it may be more difficult to see in people withdark hair. Diagnosis is confirmed by polariscopic and/or electronmicroscopic examination of affected hairs. The condition runs in an autosomal dominant fashion in some families.Reduced penetrance and variable expression has been described. Sporadiccases have also been reported.

Pili torti is a rare hair condition characterized by fragile hair. In pili torti hair has a flattened shaft with clusters of narrow twists at irregular intervals. Some cases may be inherited in autosomal dominant or autosomal recessive patterns, while others are acquired. In the inherited form, symptoms tend to be present from early childhood. It can occur alone or as part of other diseases like ectodermal dysplasias, Menke disease, Bjornstand syndrome, or Bazex syndrome. Acquired cases of pili torti may be associated with anorexia nervosa, malnutrition, oral retinoid treatment, or inflammatory scalp conditions (e.g., cutaneous lupus erythematousus). If pili torti is detected, it is necessary to investigate possible neurological disorders, hearing loss, and defects in the hair, nails, sweat glands and teeth. There is no specific treatment for this condition, but it may improve spontaneously after puberty.

Either of two diseases resulting from fungal infection of the hair shafts. Black piedra occurs mainly in and on the hairs of the scalp and is caused by Piedraia hortae; white piedra occurs in and on the hairs of the scalp, beard, moustache and genital areas and is caused by Trichosporon species.

Monilethrix is a condition that affects hair growth. Its most characteristic feature is that individual strands of hair have a beaded appearance like the beads of a necklace. The name monilethrix comes from the Latin word for necklace (monile) and the Greek word for hair (thrix). Noticeable when viewed under a microscope, the beaded appearance is due to periodic narrowing of the hair shaft. People with monilethrix also have sparse hair growth (hypotrichosis) and short, brittle hair that breaks easily.

Affected individuals usually have normal hair at birth, but the hair abnormalities develop within the first few months of life. In mild cases of monilethrix, only hair on the back of the head (occiput) or nape of the neck is affected. In more severe cases, hair over the whole scalp can be affected, as well as pubic hair, underarm hair, eyebrows, eyelashes, or hair on the arms and legs.

Occasionally, the skin and nails are involved in monilethrix. Some affected individuals have a skin condition called keratosis pilaris, which causes small bumps on the skin, especially on the scalp, neck, and arms. Affected individuals may also have abnormal fingernails or toenails.

An inherited disorder of copper metabolism transmitted as an X-linked trait and characterized by the infantile onset of HYPOTHERMIA, feeding difficulties, hypotonia, SEIZURES, bony deformities, pili torti (twisted hair), and severely impaired intellectual development. Defective copper transport across plasma and endoplasmic reticulum membranes results in copper being unavailable for the synthesis of several copper containing enzymes, including PROTEIN-LYSINE 6-OXIDASE; CERULOPLASMIN; and SUPEROXIDE DISMUTASE. Pathologic changes include defects in arterial elastin, neuronal loss, and gliosis. (From Menkes, Textbook of Child Neurology, 5th ed, p125)

Hypotrichosis simplex is a rare form of hereditary hair loss without other abnormalities. Affected individuals typically show normal hair at birth, but experience hair loss and thinning of the hair shaft that starts during early childhood and progresses with age. Hypotrichosis simplex can be divided into 2 forms: the scalp-limited form and the generalized form, in which all body hair is affected. The progressive thinning of the hair shaft is a typical feature of androgenetic alopecia. Hypotrichosis simplex can be inherited either as an autosomal dominant or autosomal recessive trait. Some cases are caused by mutations in the APCDD1 gene on chromosome 18p11. To date, there is no treatment for this condition.

Hirsutism means the growth of excessive male-pattern hair in women after puberty. It affects facial and body areas dependent on androgens, namely mustache and beard, pubic hair, buttocks, and thighs. It is a frequent reason for dermatological consultation. Hirsutism is the most common endocrine disorder affecting nearly 10% of women in the United States.

Irrespective of the cause, hirsutism can cause significant emotional stress and mental anguish. The key is to find the cause and address the cosmetic issue.

Etiology

The causes of hirsutism are variable. The condition may be of ovarian or adrenal origin, tumoral or not. The following are some examples.

Hyperandrogenic Hirsutism

Hirsutism is most often due to hyperproduction of androgens, of ovarian or adrenal origin. Hyperandrogenism of tumor origin, which is very severe, must be distinguished from non-tumor hyperandrogenism, which is often minimal or moderate.

Polycystic Ovary Syndrome (PCOS)

It represents the most common cause of hirsutism and causes about 75% of all cases. It affects 5% to 10% of women during their period of genital activity and 20% to 25% of adolescent girls. It is a heterogeneous and complex syndrome of unknown etiology characterized by the end of follicular maturation with an accumulation of small follicles under the cortex and hyperplasia of the ovarian stroma.

Hirsutism appears at puberty, accompanied by disturbances of the menstrual cycle, weight gain, dyslipidemia, insulin resistance, acne, and acanthosis nigricans. The patient reports spaniomenorrhea (prolongation of the cycle beyond 35 days), oligomenorrhea (less abundant menstruation), and infertility. The ovaries can be enlarged. Hypothyroidism or liver disease may be present.

Androgen-Secreting Tumors

Hyperandrogenism due to ovarian or adrenal tumors is rare. It is responsible for only 0.2% of all cases of hirsutism. These androgen-secreting tumors are autonomous, and therefore, do not depend on the hypothalamic-pituitary axis. Approximatively 50% of them are malignant, and in these cases, the plasma androgen levels are very high. They are also responsible for rapid-onset of virilization, hirsutism, and a pelvic or abdominal mass.

Non-classical Congenital Adrenal Hyperplasia (NCAH)

This is a common autosomal recessive disorder, caused by a partial 21-hydroxylase deficiency, and represents the most common adrenal etiology of hyperandrogenism. Its prevalence varies greatly according to the ethnicity of the patients. So it is more common in the Ashkenazi Jewish population (3.7%) and the Central European population (2%) and rare in Caucasians (0.1%). Like PCOS, NCAH can be expressed after the puberty by hirsutism, oligomenorrhea, acne, infertility, alopecia, and primary amenorrhoea.

Non-Hyperandrogenic Hirsutism

Medications

Many drugs can cause hirsutism: androgens, glucocorticosteroids, progestins, estrogen antagonists (clomiphene, tamoxifen), minoxidil, cyclosporine, danazol, diazoxide, phenytoin, D-penicillamine, and interferon.

It is important to know that hypertrichosis could also be caused by certain medications such as acetazolamide, phenytoin, latanoprost, streptomycin, psoralen, minoxidil, cyclosporine, and diazoxide.

Endocrinopathies

The responsibility of the endocrinopathies in the occurrence of hirsutism is rare, and other more specific symptoms and signs dominate the clinical picture:

• Cushing syndrome depends on adrenocorticotrophic hormone (ACTH). It can cause hirsutism, because of the stimulating nature of ACTH on the reticulated area that can cause excessive androgen secretion. The features of hypercorticism are often in the foreground.

• Hyperthyroidism or hypothyroidism is uncommonly a cause of isolated hirsutism.

• Hyperprolactinemia is manifested by amenorrhea, galactorrhea, infertility, and rarely hirsutism.

• Acromegaly is also a rare cause of isolated hirsutism.

Others Causes

Moderate hirsutism can be observed in pregnant women (physiological prolactin secretion) and postmenopausal women (relative hyperandrogenism due to the cessation of ovarian estrogen production).

Idiopathic Hirsutism

Idiopathic hirsutism defines the hirsutism that occurs in association with regular menses, normal ovarian morphology, and normal plasmatic androgen levels. It is a diagnosis of exclusion after elimination of other etiologies. It represents about 10% of all cases of hirsutism and 50% of cases of mild hirsutism. It may be due to hypersensitivity of the pilosebaceous follicle receptors to androgens and peripheral conversation induced by the 5-reductase of testosterone to dihydrotestosterone ten-fold more active on the follicle-sebaceous unit. This has genetic determinism and is frequently reported in women of East Indian and Mediterranean origin.

Epidemiology

The exact prevalence of hirsutism is not well known. It may be 10% or even higher than 50%. The psychological problem that this disease causes depends on ethnic and socio-cultural factors. Indeed, in some societies where the lack of hair is considered an important criterion of female beauty, minimal hirsutism could be considered a severe disorder, while much more pronounced hirsutism could be accepted in other societies.

Hirsutism appears to be most common in dark-skinned individuals. Hirsutism can occur in men but is difficult to recognize. In children, hirsutism is a sign of precocious puberty.

Hirsutism is also known to occur in women who discontinue the oral contraceptive pill and gain weight.

Pathophysiology

Hirsutism is an androgen-dependent disorder resulting from the interaction between circulating androgen levels and the sensitivity of the hair follicle to androgens. The skin can retain testosterone in a more active androgen, dihydrotestosterone (DHT) through a 5alpha-reductase enzyme of which there are two isoenzymes, types 1 (chromosome 5) and 2 (chromosome 2), present in the skin and the hair follicle. In addition, the skin and the pilosebaceous follicle have an androgen receptor (AR).

After exclusion of an exogenous intake of androgens, hirsutism results either from hypersecretion of androgens, from the ovary or the adrenal gland, or the increased cutaneous sensitivity of the skin to normal circulating levels of androgens. This last case is "idiopathic hirsutism."

History and Physical

The medical history is important. In the case of hirsutism of peripubertal and slow onset, it indicates primary hirsutism or non-tumoral secondary hirsutism. Late-onset or rapid progression, signs of virilization or high levels of hormones lead to adrenal (adenomas), ovarian (arrhenoblastoma), or pituitary (prolactinoma) tumors. Anamnesis of cycle disorders is an important indicator for secondary hirsutism (100% for tumors, 75% for polycystic ovaries, 0% to 25% for late adrenogenital syndrome).

The general characteristic is the sexual hair, whose density and properties change, especially in the middle areas of the body. Most often, the face, chest, areolas, white line, buttocks, sacrum, inner thighs, and external genitalia are affected. The severity of hirsutism can be quantified based on the Ferriman and Gallwey system, which evaluates nine areas of the body. For each, one assigns points from 1 to 4 are assigned according to the density of hair, ranging from the absence of hair to severe hirsutism. One can then calculate a total score; if it is greater than 7, the maximum being 36, it is considered abnormal. Other common symptoms associated with excess androgens are acne, menstrual irregularities, the temporal recession of the hairline and frontal alopecia.

Evaluation

The basic biological assessment is performed in the early follicular phase (third to the sixth day of the cycle, early morning, fasting) and after stopping possible oral contraception for two or three cycles unless a tumor cause is suspected. It comprises total testosterone, dehydroepiandrosterone sulfate (DHEAS), delta4-androstenedione (delta4A), luteinizing hormone (LH) / follicle-stimulating hormone (FSH), 17-hydroxyprogesterone (17-OHP), steroid hormone-binding globulin (SHBG). In the case of menstrual cycle disorder (amenorrhea, oligomenorrhea), the stimulating thyroid hormone (TSH) and prolactinemia (PRL) are included.

According to the clinical findings, one can add to the work up a short dexamethasone suppression test (Cushing syndrome), an adrenocorticotropic hormone (ACTH) stimulation test and a prolonged dexamethasone suppression test (late adrenogenital syndrome), a carbohydrate tolerance test or HOMA index (insulin resistance syndrome).

The diagnosis of idiopathic hirsutism is a diagnosis of exclusion. Approximately 15% to 50% of women suffering from hirsutism belong to this category. Its pathogenesis is then parallel to that of primary androgenetic alopecia.

Treatment / Management

Pharmacologic Treatment

Treatment of non-tumoral hirsutism still includes oral contraception. It inhibits by its progestogen the hypothalamic-pituitary axis, and thus the ovarian production of androgens; by its estrogen, it increases the SHBG. It is combined with an antiandrogenic treatment: flutamide, spironolactone, cyproterone acetate, finasteride are all used with variable but comparable results.

Oral contraceptives are the first treatment of choice as they suppress androgen production by the ovaries. However, they often do not work. In addition, for a female who desires a pregnancy, this treatment may not be ideal.

Spironolactone is known to block androgen receptors and is the second most common treatment. It can even be combined with an oral contraceptive. However, the improvement is slow and takes many months. Thus, compliance with spironolactone is low.

Finasteride is used to treat hirsutism and is preferred as it does not have any estrogenic or progesterone activity. However, it is not recommended in women of childbearing age as there is a risk of ambiguous genitalia in the fetus. Flutamide is another novel treatment, and while it does work, the medication is expensive and has the potential to cause liver damage.

Adrenal hyperandrogenism is slowed down by low dose corticosteroids, possibly associated with the treatments as mentioned earlier.

Fine hair growth can be inhibited by twice, daily topical application of eflornithine. Electrolysis is less used now except for coarse white hairs and also in cases of polycystic ovaries without insulin resistance.

Nonpharmacologic Treatment

As the effect of drug treatment that occurs only after 1 to 2 years, clinicians use the cosmetic approaches that are also appropriate for hypertrichoses: shaving, hair removal, discoloration by hydrogen peroxide, chemical depilation (p. thioglycolates). Fine hair growth can be inhibited by twice-daily topical application of eflornithine. Electrolysis is not used as often as in the past, except in the case of coarse white hairs. It has been replaced by long-term depilation with tools like depilatory lasers and various intense pulsed light devices.

Surgical Treatment

Surgical excision is necessary in the case of the tumoral process. Ovariectomy may be indicated for severe hyperandrogenism in menopausal or perimenopausal women.

Differential Diagnosis

Hypertrichosis is a diffuse increase of hair forming down in areas not dependent on androgens (often the cheeks and arms). It may be the consequence of an excess of glucocorticoids, the taking of certain drugs (phenytoin, penicillamine, ciclosporin, minoxidil, diazoxide), and systemic disorders (anorexia nervosa, hypothyroidism, porphyria, dermatomyositis). Hypertrichosis is often due to a familial or ethnic character and has a prepubertal onset.

Lanugo is a very thin, villous, and non-pigmented hair located anywhere on the body. Hypertrichosis is characterized by an excessive growth of hair affecting normally hairy areas in women.

Inflammation of follicles, primarily hair follicles.

Uncombable hair syndrome (UHS) is a rare disorder of the hair shaft of the scalp. It is usually characterized by silvery-blond or straw-colored hair that is disorderly; stands out from the scalp; and cannot be combed flat. It may first become apparent from 3 months of age to 12 years of age. Most cases are isolated, but in some cases it has been described in association with other diseases, such as ectodermal dysplasias, Bork syndrome and Angel-shaped phalangoepiphyseal dysplasia. The syndrome has been found to be caused by mutations in the genes PADI3, TGM3, and TCHH. These three genes code for proteins that are involved in hair shaft formation. The syndrome appears to be inherited in an autosomal recessive fashion; however, cases inherited in an autosomal dominant manner may also exist, as there are other genes involved in hair formation. The condition often spontaneously regresses in late childhood. Some published studies suggest that biotin may improve the condition.

Uncombable hair syndrome is a condition that is characterized by dry, frizzy hair that cannot be combed flat. This condition develops in childhood, often between infancy and age 3, but can appear as late as age 12. Affected children have light-colored hair, described as blond or silvery with a glistening sheen. The hair does not grow downward but out from the scalp in multiple directions. Despite its appearance, the hair is not fragile or brittle, and it grows at a normal or slightly slower rate. Only scalp hair is affected in uncombable hair syndrome.

For unknown reasons, this condition usually improves over time. By adolescence individuals with uncombable hair syndrome have hair that lies flat and has normal or nearly normal texture.

The prevalence of uncombable hair syndrome is unknown; at least 100 cases have been described in the scientific literature. There are likely more people who are undiagnosed because adults who seem unaffected may have had uncombable hair syndrome in childhood.

Superficial Staphylococcal Infections

S. aureus is often associated with pyoderma, skin infections that are purulent. Pus formation occurs because many strains of S. aureus produce leukocidins, which kill white blood cells. These purulent skin infections may initially manifest as folliculitis, but can lead to furuncles or deeper abscesses called carbuncles.

Folliculitis generally presents as bumps and pimples that may be itchy, red, and/or pus-filled. In some cases, folliculitis is self-limiting, but if it continues for more than a few days, worsens, or returns repeatedly, it may require medical treatment. Sweat, skin injuries, ingrown hairs, tight clothing, irritation from shaving, and skin conditions can all contribute to folliculitis. Avoidance of tight clothing and skin irritation can help to prevent infection, but topical antibiotics (and sometimes other treatments) may also help. Folliculitis can be identified by skin inspection; treatment is generally started without first culturing and identifying the causative agent.

In contrast, furuncles (boils) are deeper infections (Figure). They are most common in those individuals (especially young adults and teenagers) who play contact sports, share athletic equipment, have poor nutrition, live in close quarters, or have weakened immune systems. Good hygiene and skin care can often help to prevent furuncles from becoming more infective, and they generally resolve on their own. However, if furuncles spread, increase in number or size, or lead to systemic symptoms such as fever and chills, then medical care is needed. They may sometimes need to be drained (at which time the pathogens can be cultured) and treated with antibiotics.

When multiple boils develop into a deeper lesion, it is called a carbuncle (Figure). Because carbunclesare deeper, they are more commonly associated with systemic symptoms and a general feeling of illness. Larger, recurrent, or worsening carbuncles require medical treatment, as do those associated with signs of illness such as fever. Carbuncles generally need to be drained and treated with antibiotics. While carbuncles are relatively easy to identify visually, culturing and laboratory analysis of the wound may be recommended for some infections because antibiotic resistance is relatively common.

Proper hygiene is important to prevent these types of skin infections or to prevent the progression of existing infections.

Trichorrhexis nodosa is a disorder of the hair shaft characterized by easy breakability of hair and microscopically by nodes on the hair shaft 1. Trichorrhexis nodosa may be congenital or acquired. The more common acquired form results from repeated trauma to the hair shaft.

What is an ingrown hair?

An ingrown hair occurs when you cut a hair and it grows back into the skin, causing inflammation. It can happen anywhere on the body that hair is removed from, such as through shaving, tweezing, waxing or using hair removal cream.

Sometimes an ingrown hair can cause an infection around the hair follicle, known as folliculitis.

Common places for ingrown hairs are:

• men’s chins, cheeks and necks
• women’s legs, pubic areas and armpits
• buttocks

What are the symptoms of an ingrown hair?

The area around the ingrown hair can become swollen, red and itchy. It can become inflamed so that it is painful and looks like a pimple with pus. Ingrown hairs can form cysts (sacs of fluid beneath the skin) which can range from a small painless lump to a large, infected swelling.

What causes an ingrown hair?

There are 2 causes of ingrown hair.

1. Cutting a hair can force it back into its follicle.
2. Dead skin can clog the follicle, causing the hair to grow under the skin or re-enter its follicle or one nearby. The hair then grows inward instead of pushing through the surface of the skin.

You are more likely to get ingrown hairs if you have very curly or coarse hair. Cutting curly or coarse hair can lead to a type of ingrown hair called pseudofolliculitis or ‘razor bumps’ after shaving, tweezing or waxing hair in the area.

How is an ingrown hair treated?

Ingrown hairs often improve without treatment. It may help to stop shaving, tweezing, waxing or using hair removal cream until the condition improves.

Washing the area with a washcloth or soft toothbrush using a circular motion for several minutes can help release the hairs. You can also try inserting a sterile needle under the hair loop and pulling the ingrown end to the surface.

If the ingrown hair becomes infected, you may need an antibiotic cream from the doctor. In severe cases, oral antibiotics may be needed.

Talk to your doctor if you have a lot of ingrown hairs. There are medicines that can remove dead skin cells, reduce inflammation and treat infection.

Can ingrown hair be prevented?

You might be able to prevent ingrown hairs by:

• washing your skin with warm water and a mild facial cleanser
• exfoliating before you shave
• using a single blade or electric razor
• shaving in the direction of the hairs
• using shaving creams to cleanse the area

Alopecia areata is a common disorder that causes hair loss. "Alopecia" is a Latin term that means baldness, and "areata" refers to the patchy nature of the hair loss that is typically seen with this condition.

In most people with alopecia areata, hair falls out in small, round patches, leaving coin-sized areas of bare skin. This patchy hair loss occurs most often on the scalp but can affect other parts of the body as well. Uncommonly, the hair loss involves the entire scalp (in which case the condition is known as alopecia totalis) or the whole body (alopecia universalis). Other rare forms of alopecia areata, which have different patterns of hair loss, have also been reported.

Alopecia areata affects people of all ages, although it most commonly appears in adolescence or early adulthood. Hair loss occurs over a period of weeks. The hair usually grows back after several months, although it may fall out again. In some cases, unpredictable cycles of hair loss followed by regrowth can last for years. In addition to hair loss, some affected individuals have fingernail and toenail abnormalities, such as pits on the surface of the nails.

The hair loss associated with alopecia areata is not painful or disabling. However, it causes changes in a person's appearance that can profoundly affect quality of life and self-esteem. In some people, the condition can lead to depression, anxiety, and other emotional or psychological issues.

Hair transplant surgery is a cosmetic procedure designed to address hair loss by moving healthy, hair-bearing skin from one part of the scalp to areas experiencing thinning or baldness. It is most commonly used to treat male pattern baldness (androgenetic alopecia) but can also help with hair loss caused by scalp injuries, burns, or certain inflammatory diseases like lichen planus, lupus, or morphea.

When is Hair Transplant Recommended?

The surgery can benefit those experiencing permanent hair loss, whether from genetic conditions, trauma, or disease. However, it is not a cure for male pattern baldness, as the procedure does not prevent future hair loss. Men with progressive baldness may need additional treatments, such as medications (e.g., minoxidil or prescription drugs), to maintain results over time.

How the Procedure Works

Hair transplantation is usually performed in a doctor’s office under local anesthesia to numb the scalp, with optional medication to help the patient relax. The process involves the following key steps:

1. Donor Area Preparation:

   • Hair is removed from areas of dense growth (usually the back or sides of the scalp) using a scalpel or other tools, including robotic assistance in some cases.
   • The scalp at the donor site is closed with stitches.

2. Hair Follicle Extraction:

   • The removed scalp tissue is carefully dissected under magnification to isolate individual hairs or small hair groups.

3. Recipient Area Preparation:

   • The bald or thinning area is cleaned, and tiny incisions are made to receive the new hairs.

4. Transplantation:

   • Healthy hair follicles are meticulously placed into the incisions. Depending on the extent of the hair loss, hundreds or thousands of hairs may be transplanted in a single session.

Things to Consider

Hair transplantation can significantly improve appearance and self-confidence but has limitations. It addresses only visible hair loss and does not halt the underlying balding process. Many individuals may need a combination of surgery and medical treatments to achieve the best long-term outcomes. Some people also explore non-surgical alternatives, such as medications or self-acceptance, to manage the effects of hair loss.

In summary, hair transplant surgery offers a promising solution for many types of hair loss, though it requires careful planning and, often, ongoing treatment to maintain optimal results.

Introduction

Hair loss is a common concern, affecting approximately 67% of males and 24% of females. Several non-surgical treatments, including minoxidil, finasteride, dutasteride, low-level laser light therapy, platelet-rich plasma, adenosine, and ketoconazole, can slow hair loss and stimulate new hair growth. Hair transplantation, through follicular-unit grafting, is the preferred surgical method for individuals with specific forms of alopecia seeking hair restoration. This procedure assists them in attaining a more natural and voluminous hair appearance.

The most frequent cause of hair loss is androgenic alopecia (AGA), now commonly known as male pattern hair loss (MPHL) and female pattern hair loss (FPHL). Individuals with androgenic alopecia experience the miniaturization of hair follicles in susceptible areas of the scalp. Ideal candidates for hair transplantation are those with stable androgenetic alopecia with a sufficient hair reservoir for transplantation.

Diagnosing androgenic alopecia is typically straightforward and relies on recognizing the characteristic patterns of hair loss, the miniaturization and depigmentation of hair, and the absence of clinical inflammation. If these features are absent, further evaluation may be necessary. The Norwood classification system best illustrates male pattern hair loss, while women use the Ludwig classification. Androgenic alopecia in women typically spares the hairline but presents with more diffuse thinning throughout the top and upper sides of the head.

During the hair transplantation procedure, healthcare professionals transfer androgen-resistant hair follicular units from the occipital region to the areas affected by alopecia. Two primary methods for harvesting donor's hair exist: hair follicular unit strip surgery (FUSS) and follicular unit extraction (FUE). Follicular unit extraction is preferred for younger men and those who prefer shorter hairstyles because it avoids creating a linear donor site scar. Since occipital hairs are resistant to androgens, the transplanted hairs retain the characteristics of the donor hair, maintaining their larger caliber as they grow.

Anatomy and Physiology

Pertinent Anatomy and Definitions

The scalp has 5 layers.

• Skin
• Connective subcutaneous tissue
• Galea aponeurosis
• Loose connective tissue
• Periosteum over the cranium

The skin and subcutaneous tissue contain the hair follicles. These 2 layers undergo thinning in patients affected by alopecia. The subcutaneous layer is quite vascular. Staying superficial along the connective subcutaneous tissue layer during hair transplantation prevents a disruption in blood supply.

Hair follicle

The hair shaft, inner and outer surrounding sheaths, and a germinative bulb comprise the hair follicle. The follicle divides into 3 sections:

• The infundibulum begins at the surface of the epidermis and extends to the opening of the sebaceous duct.
• The isthmus is between the sebaceous duct opening and the bulge or arrector pili muscle insertion.
• The inferior segment extends from the bulge to the base of the follicle.

Bulb

The bulb is the deepest segment of the hair follicle, containing the hair matrix, dermal papilla, and melanocytes. The hair matrix creates the hair shaft, the dermal papilla regulates growth, and melanocytes provide color.

Follicular unit

A follicular unit (FU) is a naturally occurring group of hair(s) dispersed throughout the scalp consisting of 1 to 4 terminal hairs, a sebaceous gland and duct, and an arrector pili muscle. The collagen band surrounding the FU is the perifolliculum. Approximately 50% of the scalp contains no hair follicles. Transplantation of only the follicular-unit bundles provides the most optimal cosmetic results.

Hair Growth Cycle

Anagen

Anagen is the active growing phase of the hair follicle, lasting 2 to 6 years. Approximately 90% to 95% of scalp hairs are in anagen at any time.

Catagen

Catagen refers to the involutional phase of the hair follicle characterized by acute follicular regression. Catagen typically lasts 2 to 3 weeks, and less than 1% of scalp hairs are in catagen at any given time.

Telogen

Telogen refers to the resting phase of the hair follicle lasting 2 to 3 months, characterized by a stop in all activity. Approximately 5% to 10% of scalp hairs are in telogen at a time.

Exogen

Exogen is the daily shedding of hair follicles characterized by a loss of 25 to 100 telogen hairs, replaced by new anagen hairs.

A donor site is a non-alopecic site used to harvest donor terminal hairs for implantation. The safe donor site of the scalp lies in the mid-occipital region between the upper and lower occipital protuberances. In general, there are 65 to 85 FUs per cm² in the occipital donor scalp. Notably, hairs are finer in the inferior portion of the donor area and coarsest at the superior margin. The donor site represents the primary limiting factor in hair transplantation, regardless of the technique employed. In general, harvesting more than 15 to 20 FU per cm² is ill-advised, as this may cause donor site thinning. If necessary, the parietal scalp, submental region, chest, and other body parts may be used as donor sites, though data regarding efficacy is limited, and the hair characteristics may be very different from scalp hairs.

Androgenetic Alopecia

Androgenic alopecia is the most common etiology of hair loss where androgenetic effects, namely testosterone and dihydrotestosterone (DHT), disrupt the growth cycle, and the anagen-to-telogen ratio decreases. The enzyme 5-alpha reductase converts testosterone to dihydrotestosterone that links to susceptible hair follicles, causing miniaturization of the hair. The conversion to DHT occurs in the bloodstream and the scalp. Hallmark characteristics of AGA include thinning and subsequent miniaturization of the androgen-sensitive, thick, pigmented terminal hair at the top of the scalp, beard, axillary, and pubic regions. Terminal hair converts into vellus hair or fine, short, non-pigmented hair found in adults that covers much of the body. The hair elsewhere, including the parietal and occipital scalp, is androgen-insensitive.

Indications

The ideal candidate for hair transplantation has a healthy scalp, good general overall health, good donor area hair, and reasonable expectations. The indications for hair transplantation are:

• Male and female pattern hair loss
  • Norwood stage III to V for men and Ludwig stage II for women
• Traction alopecia
• Frontal fibrosing alopecia
• Lichen planopilaris
• Folliculitis decalvans
• Pubic, facial, and body hair placement for transgender patients
• Facial hair restoration for eyebrows, beards, and sideburns after facial trauma or burns

The active phase of frontal fibrosing alopecia, lichen planopilaris, and folliculitis decalvans is a contraindication to HT. Patients affected by folliculitis decalvans must have had no active disease for several years before attempting HT.

Contraindications

Patients inquiring about hair transplantation require a thorough history and physical examination. Key details of the patient's history are:

• Hair loss history and associated symptoms
• • Fever, pruritus, scaling, erythema, and rash suggest an inflammatory condition.
• Medical history
• • Dermatologic conditions, thyroid disease, diabetes, metabolic syndrome, autoimmune-related conditions, systemic infections, local infections, malnutrition or vitamin and mineral deficiency, recent childbirth, history of scar formation, chemotherapy, and radiation exposure can all affect results.
• Medications
• • Medications like propranolol, coumadin, and amphetamines can affect hair growth. Additionally, stopping antiplatelet and anticoagulation medications prior to HT will mitigate bleeding risk.
• Psychiatric history
• • Stress, anxiety, eating disorders, trichotillomania, emotional trauma, and body dysmorphic disorder all place the patient at a higher risk for dissatisfaction.
• Physical exam
• • Localized, scarring, or inflammatory hair loss suggests a diagnosis other than androgenic alopecia. Additionally, a positive hair pull test suggests an alternate diagnosis.

The following list contains contraindications to hair transplants and medical conditions that can lead to complications after hair transplantation.

Diffuse Unpatterned Alopecia

Donor hair must be retrieved from a portion of the scalp not affected by alopecia. Hair loss should be limited to the top of the head. If the patient has no such area on the scalp, then hair transplantation will not be successful.

Cicatricial Alopecias

Cicatricial alopecias are inflammatory conditions that destroy hair follicles, causing scarring and permanent hair loss. Examples are lichen plano pilaris (LPP) and discoid lupus erythematosus. Hair transplantation is contraindicated during active cicatricial alopecias as the likelihood of failure is high, and transplant can worsen the disease. Once the patient has had no active disease for 2 years, HT can take place. The patient must understand that results will likely be suboptimal.

Alopecia Areata

Alopecia areata (AA) is an autoimmune alopecia affecting the hair follicles. After 2 years with no active disease, patients can attempt HT. Again, the results will likely be suboptimal, and a risk of recurrent disease exists.

Patients with Unstable Hair Loss

Patients currently undergoing a rapid degree of hair loss or who have more than 15% miniaturization in the area to be transplanted should receive medical therapy for 6 to 12 months to allow for stabilization prior to hair transplantation.

Patients with Insufficient Hair Loss

Fifty percent of native hair must be lost before hair loss becomes noticeable. Fifty percent hair loss is the threshold for HT. Patients with 50% hair loss should use medical therapy until that time.

Young Patients

Young patients who develop MPHL often progress rapidly. Performing HT early will deplete their donor supply and not provide the best long-term outcome. The best management is deferment with medical therapy for at least 1 year with reconsideration of HT at that time. Ideally, HT should occur after age 25.

Patients with Unrealistic Expectations

Patients must understand that hair will not be restored to or exceed pre-balding amounts. Some scalp will still be visible, and some scarring will occur. The goal is to create the illusion of density.

Patients with Psychological Disorders

Patients with body dysmorphic disorder (BDD) are at a high risk of being dissatisfied with the outcome. Recognition of patients with BDD is imperative. Affected patients focus on absent or perceived minor defects that are not evident to the general population. They spend hours each day fixated on the defect and have likely undergone multiple cosmetic procedures. Trichotillomania is an obsessive-compulsive disorder marked by the recurrent pulling out of one's hair.

Medical Conditions that Complicate Hair Transplantation

• Smoking
• Diabetes with microvascular damage
• Advanced balding
• Hypertension
• Advanced sun damage to the scalp

Equipment

• Operating room (OR) measuring a minimum of 3.6 x 3.6 m with a minimum height of 3.0 m
• A dissection room of equal size to the minimum requirement for the operating room or one large room measuring 6 x 3.6 m
• An OR door measuring wider than 0.6 m to allow for a stretcher in the event of an emergency
• Fluorescent lamp at the rate of 1 W per 0.09 m²
• Autoclave or chemical method to sterilize instruments
• Blood pressure monitor
• Stethoscope
• Pulse oximeter
• Glucometer
• Digital thermometer
• Weighing scale
• Local anesthesia with or without epinephrine
  • lignocaine with a maximum daily dose of 300 mg or 4.5 mg/kg of body weight that can be increased to 500 mg or 7 mg/kg after adding epinephrine
  • bupivacaine with a maximum daily dose of 175 mg
  • levobupivacaine with or without epinephrine with a maximum dose of 2 mg/kg and a maximum one-time dose of 200 mg
  • maximum dose of epinephrine is 0.01 mg/kg body weight
• Tumescent saline
• Comfortable, ergonomic chairs and tables
• Magnification with microscopes and high-powered loupes
• Topical antiseptic
• Scalpel for strip harvest if applicable
• Skin retractors
• FUE punch devices
• Micro-forceps
• Graft holding solution
• Cotton-tip applicators
• Suture or staples for skin closure if the strip method is employed
• Non-adhesive dressing
• Petroleum jelly or antibiotic ointment

Necessary in the Event of an Emergency

1. Intravenous access cannulas and IV sets
2. Laryngoscope
3. Endotracheal tubes
4. Suction equipment
5. Xylocaine spray
6. Oropharyngeal and nasopharyngeal airways
7. Ambu Bag
8. Oxygen cylinders with flow meter, tubing, catheter, face mask, and nasal prongs
9. Defibrillator with accessories
10. Electrocardiogram machine
11. Injectible adrenaline 1 mg
12. Injectible hydrocortisone 100 mg
13. Injectible atropine 1 mL
14. Injectible pheniramine maleate 10 mL
15. Injectible promethazine 1 mL
16. Injectible furosemide 4 mL
17. Injectible metoclopramide 2 mL
18. Injectible dexamethasone 2 mL
19. Injectible diazepam 10 mL
20. Injectible dicyclomine hydrochloride 2 mL
21. Injectible 5% dextrose infusion 100 mL
22. Injectible normal saline 500 mL

Personnel

Contemporary hair transplantation requires:

• Surgeon
  • The surgeon will mark the hairline, harvest the grafts from the donor site, and closely supervise the quality of graft creation and placement by the technicians.
  • Hair technicians
    • Typically 1 to 4 technicians are necessary depending on the technique used, surgeon involvement, and number of grafts required.
• Operative nurse
• Surgical scrub technician

At least one surgical assistant or technician needs basic life support and advanced cardiac life support training.

Preparation

Mathematically speaking, hairs with larger shaft diameters provide exponentially more surface area coverage; therefore, patients with thicker-caliber hair can expect to obtain much denser coverage versus patients with thin-caliber hair. Patients whose scalp donor sites have greater than 80 FUs per cm² are excellent candidates. Those with donor hair density of less than 40 FUs per cm² are considered poor candidates for HT, and the clinician needs to set patient expectations accordingly.[7][12]

Patients hoping to correct frontal baldness can expect the most dramatic results and thus represent great candidates. Grafting only the scalp vertex should be avoided if possible, as this not only consumes potential future donor grafts but also may cause a “doughnut” appearance as hair loss progression continues. Concentrating grafts in the frontal scalp will provide the maximum long-term density and minimize aesthetic risk. The patient must also understand the need for a conservative approach when recreating the anterior hairline to have a natural appearance that lasts.

Light-skinned individuals and patients with light-colored hair are preferable to those with black hair since the color contrast between hair and skin is less noticeable. Proper technique helps mitigate most problems with transplanting dark-haired patients.

Patients must have realistic expectations and understand that multiple hair transplantation sessions may be necessary to achieve the desired results.

Preoperative Testing

• Complete blood count, including platelets
• Prothrombin time (PT)
• Activated partial thromboplastin time (aPTT)
• Consider total iron and ferritin, thyroid function tests and thyroid-stimulating hormone, total and free testosterone, and dehydroepiandrosterone (DHEA) sulfate in female patients
• Fasting blood glucose and hemoglobin A1c in patients with diabetes
• Consider HIV, hepatitis B, and hepatitis C
• Scalp biopsy or KOH preparations if the clinician suspects an infectious or inflammatory cause of alopecia

A routine electrocardiogram is not necessary unless the patient has a history of cardiac disease, morbid obesity, or metabolic syndrome.

Patient Instructions Prior to Surgery

1. Stop minoxidil 1 week prior to the procedure.
2. Avoid alcohol for 7 days before and after the procedure.
3. Smoking should be reduced as much as possible before the surgery, and for best results, stop entirely.
4. Provide preoperative anxiolytics such as alprazolam in an anxious patient.
5. Discontinue non-steroidal anti-inflammatory medications 12 to 24 h before surgery.
6. Continue antihypertensives except for beta-blockers on the day of surgery.
7. Avoid vitamin supplements and herbal preparations 3 weeks before surgery.
8. Manage antiplatelet and anticoagulant medications based on risks vs benefits.
9. Shower or bathe with soap or povidone-iodine + shampoo the night before and on the morning of surgery.

Patient Preparation on the Day of Surgery

1. A single dose of preoperative systemic steroids, such as 40 mg of prednisone, may help with scalp swelling.
2. Administer preoperative antibiotic prophylaxis with cephalosporins or a macrolide or clindamycin in patients allergic to penicillin.
3. Mark the recipient area, including the proposed hairline, along with the direction and pattern of native FUs.
4. Shave and mark the donor site according to the technique employed.
5. Obtain anesthesia using a combination of local injections and regional nerve blocks (supraorbital, supratrochlear, zygomaticofrontal, and occipital).
6. Infiltrate tumescent anesthesia and tumescent saline into the proposed donor and implantation sites to facilitate graft harvest and placement, respectively.

Calculate the desired recipient graft number or total number of grafts needed by multiplying the measured recipient area by the desired graft density. The target density should be around 30 FUs per cm². If planning FUT for graft harvest, calculate the strip length by dividing the desired recipient graft number by the donor site density using a densitometer. The strip should be approximately 1 to 1.5 cm wide but no larger to allow tension-free wound closure.

Postoperative Care and Instructions

• Sleep with the head-end of the bed elevated 15° to 30° during the first week after surgery to minimize swelling.
• Avoid heavy lifting and strenuous activity for 1 week following surgery.]
• Place ice on the forehead, not the grafts, for 20 minutes every 2 to 3 hours for the first few days.
• Use minoxidil 5% bid in the recipient and donor area, beginning 5 to 7 days after surgery.
• Regularly wash with normal saline for the first few days until neovascularization occurs.
• Wash with baby shampoo after 3 days.

Technique or Treatment

Historically, surgeons used plug grafts, scalp reductions, and transposition flaps to treat androgenic alopecia. Currently, hair transplantation comprises 99% of the surgical management of hair loss.

Harvesting of FUs occurs in strips (FUSS) or individually (FUE). Currently, FUE represents the more common approach due to its potential advantages over FUT, which include:

• An increased number of harvestable grafts;
• Less apparent scarring;
• Donor site laxity and density are not a significant deterrent;
• Less postoperative pain;
• Decreased postoperative healing time;
• Allows targeting of follicular groups of a specific size or hairs with a specific diameter or pigmentation; and
• The surgeon can target hairs outside the typical donor site, such as the parietal scalp, chest, back, beard, and pubis, if needed.

On the contrary, FUT may be preferable to FUE given FUT’s reported advantages, which include:

• Shorter operative time
• Less transection of follicles
• Less bleeding at the donor site
• The single strip provides 1000 to 1500 grafts
• The placement of individual FU in each slit gives a denser packing and cosmetically better results

Still, controversy remains as to which hair transplantation procedure is superior. Though FUE operative time is typically longer than FUT, automated mechanical instruments and robotic technology used in FUE extraction may close this operative time gap by offering decreased extraction times compared to the traditional, manual FUE techniques.

In summary, both FUT and FUE represent powerful techniques for improving the aesthetic appearance of the hair, and the astute hair transplantation surgeon should be knowledgeable of the nuances of each.

FUT Donor Site Harvest

• Place the patient in a prone position;
• Trim the donor site hair to 2 mm;
• Mark the calculated strip length;
• Inject local anesthetic superficially into the dermis;
• Inject a tumescent solution to increase anesthesia, hemostasis, and dermal turgor;
• Make a beveled incision parallel to the exiting follicles, into but not beyond the subcutaneous tissue, approximately 4 to 5 mm deep;
• With lateral retraction around the periphery using sharp skin hooks, dissect away the donor strip from the galea aponeurosis and occipital fascia;
• Use cauterization sparingly to decrease the risk of permanent FU damage;
• Remove excess subcutaneous tissue from the donor strip, leaving 2 mm of fat beneath the FU to avoid damage to the follicle;
• Dissect the strip under magnification into vertical segments 1 FU thick;
• Isolate individual FUs with further sharp strip dissection and place them immediately into a holding medium of chilled saline;
• • The FU is susceptible to desiccation in just a few minutes, which renders the graft unusable;
• Once harvested, close the donor strip with a two-layer closure using sutures and staples per surgeon preference; and
• The patient transitions to a sitting position for recipient site preparation and graft implantation.

FUE Donor Site Harvest

• Shave the donor site to 2 mm to visualize the angle of the follicles;
• Place the patient in a prone position for ease of harvesting; and
• Inject local and tumescent anesthesia into the donor site.

Manual Follicular Unit Excision

• Orient a 0.8 to 1.2 mm sharp punch within the center of the hair follicle at the same angle and advance in an oscillating motion to a depth of 4 mm or less to prevent transection;
• Remove the FU using delicate forceps in an atraumatic fashion and place either directly onto the recipient site or a holding medium of chilled sterile saline;
• Transition the patient to a seated position in preparation for recipient site implantation.

Modifications of the manual sharp FUE technique are the manual dull punch technique, powered devices with oscillatory or rotating punches, or a vacuum apparatus to facilitate atraumatic extraction. A 5% transection rate is generally acceptable.

Recipient Site Creation and Implantation

• To avoid trauma, manipulate grafts using only the perifollicular tissue;
• Create recipient sites in a random and irregular pattern under magnification using either flat-edged blades or a combination of 19 gauge or 21 gauge needles, with care not to transect the native follicles;
• Place the graft gently into the recipient site, with light pressure applied for several seconds using a wet cotton-tip applicator to promote hemostasis and to avoid graft extrusion or “popping;” and
• Place an emollient or antibiotic ointment and a non-adhesive bandage across the donor sites.

Attention to the recipient's hair pattern is essential to promote a natural-looking result. For example, hair along the frontal scalp hairline points anteriorly at an angle of 15 to 20 degrees, while hair follicles in the temporal region are oriented inferiorly. The surgeon strives to recreate a sharp temporal recess in males and a rounded temporal recess in females. To create a natural result, follow the angles and spiraled orientation of the crown.

More recently, robotic devices harvest follicular units, resulting in more accurate and faster graft harvesting, decreased FU transection rate, and increased implantation accuracy at the recipient site, though comparative studies are lacking. Regardless, the robot offers a promising technique to maximize HT outcomes.

Complications

The vigorous blood supply to the scalp allows for quick healing and low infection rates. Nevertheless, potential complications exist:

• Edema;
• Pain;
• Bleeding;
• Folliculitis;
• Allergic reactions to lignocaine;
• Lignocaine overdosage;
• Scalp cellulitis;
• Temporary or permanent numbness of the scalp;
• Telogen effluvium;
• Epidermal cysts and ingrown hair; and
• Infection.

Telogen effluvium is an uncommon but concerning complication characterized by the shedding of native hairs at the donor or recipient site. This "shock" loss, likely a result of stress and microtrauma sustained during HT, is transient. Patients should receive reassurance that the majority of the hair shed will return at 3 to 4 months. Sensation to the frontal scalp can diminish for several weeks upon creating many graft recipient sites along the hairline. Epidermal cysts and ingrown hair, although self-limited, may rarely set off a diffuse inflammatory response affecting the entire graft population. Releasing entrapped hairs should hasten resolution.

Clinical Significance

Alopecia causes diminished self-esteem and social withdrawal in patients. Hair transplantation represents a powerful tool that can restore a more youthful appearance to those affected by androgenic alopecia, restore facial hair to patients who have experienced trauma or burns, and aid in hair placement for transgender patients. When performing hair transplantation, proper patient evaluation and execution of a comprehensive treatment plan can produce safe, reliable, and satisfactory outcomes.

Enhancing Healthcare Team Outcomes

Patients who desire hair transplantation are at an increased risk of complications and treatment failure if not properly evaluated prior to undergoing HT. A thorough assessment of patients who desire hair transplants requires an interprofessional team approach that begins before the HT and includes members of dermatology, primary care, plastic surgery, and pharmacy. Patients require evaluation by their healthcare professional for potential reversible causes of hair loss. Referral to a dermatology provider is appropriate for suspected inflammatory causes, and pharmacists are essential to help monitor drug interactions.

Potential candidates require screening by a surgeon experienced in selecting the appropriate patient for HT. During the procedure, an experienced surgeon, hair technician, and operative nurse should be involved to provide the best possible outcomes and decrease morbidity. Members of the healthcare team must effectively communicate patient education. Close follow-up during the initial postoperative period is essential to monitor for complications, including infection or hematoma. This interprofessional approach will produce the best patient outcomes with minimal adverse events.