Your toenails and fingernails protect the tissues of your toes and fingers. They are made up of layers of a hardened protein called keratin, which is also in your hair and skin. The health of your nails can be a clue to your overall health. Healthy nails are usually smooth and consistent in color. Specific types of nail discoloration and changes in growth rate can be signs of lung, heart, kidney, and liver diseases, as well as diabetes and anemia. White spots and vertical ridges are harmless.

Nail problems that sometimes require treatment include

• Bacterial and fungal infections
• Ingrown nails
• Tumors
• Warts

Keeping your nails clean, dry, and trimmed can help you avoid some problems. Do not remove the cuticle, which can cause infection.

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. 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.

Nail bed is a layer of epidermis upon which the nail body forms.

Nail body is the main keratinous plate that forms the nail.

Nail cuticle is the fold of epithelium that extends over the nail bed, also called the eponychium.

Nail fold is the old of epithelium at that extend over the sides of the nail body, holding it in place.

Nail root is the part of the nail that is lodged deep in the epidermis from which the nail grows.

Manicures and pedicures can be pretty. The cosmetic products used, such as nail polishes and nail polish removers, also must be safe—and are regulated by the U.S. Food and Drug Administration.

The FDA also regulates devices used to dry (or “cure”) artificial nails or gel nail polish as electronic products because they emit radiation.

You can do your part to stay safe (and look polished, too) by following all labeled directions and paying attention to any warning statements listed on these products.

Cosmetic Nail Care Products: Ingredients and Warnings

Cosmetic ingredients (except most color additives) and products, including nail products, do not need FDA approval before they go on the market.

But these products are required to be safe when used as intended. (Note that nail products intended to treat medical problems are classified as drugs and do require FDA approval.)

Cosmetic nail care products also must include any instructions or warnings needed to use them safely. For example:

• Some nail products can catch fire easily so you should not expose them to flames (such as from a lit cigarette) or heat sources (such as a curling iron).
• Some can injure your eyes, so you should avoid this exposure.
• Some should only be used in areas with good air circulation (ventilation).
• Some ingredients can be harmful if swallowed, so these products should never be consumed by any person or pet.

Also know that retail cosmetics such as those sold in stores or online must list ingredients in the order of decreasing amounts. If you’re concerned about certain ingredients, you can check the label and avoid using products with those ingredients.

For example, some nail hardeners and nail polishes may contain formaldehyde, which can cause skin irritation or an allergic reaction. And acrylics, used in some artificial nails and sometimes in nail polishes, can cause allergic reactions. (To learn more about ingredients, visit the FDA’s nail care products webpage.)

The bottom line? Read the labels of cosmetic products and follow all instructions. And if you go to a salon for a manicure or pedicure, make sure the space has good ventilation.

Note: Nail salon practices are regulated by the states, and not the FDA. If you’re a nail salon owner or employee, you can find information on maintaining safe salons on the webpage of the U.S. Department of Labor’s Occupational and Health Safety Administration.

If you have questions about whether certain nail products are right for you, talk to your health care provider.

About Nail Drying and Curing Lamps—and UV Exposure

Ultraviolet (UV) nail curing lamps are table-top size units used to dry or “cure” acrylic or gel nails and gel nail polish. These devices are used in salons and sold online. They feature lamps or LEDs that emit UV (ultraviolet) radiation. (Nail curing lamps are different than sunlamps, which are sometimes called “tanning beds.” You can learn more about the risks of sunlamps on the FDA’s website.)

Exposure to UV radiation can cause damage to your skin, especially if you’re exposed over time. For example, it can lead to premature wrinkles, age spots, and even skin cancer.

But the FDA views nail curing lamps as low risk when used as directed by the label. For example, a 2013 published study indicated that—even for the worst case lamp that was evaluated—30 minutes of daily exposure to this lamp was below the occupational exposure limits for UV radiation. (Note that these limits only apply to normal, healthy people and not to people who may have a condition that makes them extra sensitive to UV radiation.)

To date, the FDA has not received any reports of burns or skin cancer attributed to these lamps.

That said, if you’re concerned about potential risks from UV exposure, you can avoid using these lamps.

You may particularly want to avoid these lamps if you’re using certain medications or supplements that make you more sensitive to UV rays. These medications include some antibiotics, oral contraceptives, and estrogens—and supplements can include St. John’s Wort. See an extended list of medications that can cause sun sensitivity on the FDA’s website.

Also remove cosmetics, fragrances, and skin care products (except sunscreen!) before using these lamps, as some of these products can make you more sensitive to UV rays.

If you have questions about using nail drying or curing lamps, consult a health care professional.

And if you do choose to use these devices, you can reduce UV exposure by:

• Wearing UV-absorbing gloves that expose only your nails.
• Wearing a broad-spectrum sunscreen with an SPF of 15 or higher. (Since nail treatments can include exposure to water, follow the sunscreen’s labeled directions for use in these situations.)

Finally, nail curing lamps usually come with instructions for exposure time. The shorter your exposure, the less risky the exposure, in general. So always follow labeled directions when available. In general, you should not use these devices for more than 10 minutes per hand, per session.

How to Report Problems with Nail Care Products

If you ever have a bad reaction to a cosmetic nail product or nail curing lamp, please consult your health care provider and then tell the FDA.

You can call an FDA Consumer Complaint Coordinator (phone numbers for your area are online) or report the problem via MedWatch, the FDA Safety Information and Adverse Event Reporting program.

July 6, 2017

Appropriate hand hygiene includes diligently cleaning and trimming fingernails, which may harbor dirt and germs and can contribute to the spread of some infections, such as pinworms. Fingernails should be kept short, and the undersides should be cleaned frequently with soap and water. Because of their length, longer fingernails can harbor more dirt and bacteria than short nails, thus potentially contributing to the spread of infection.

Before clipping or grooming nails, all equipment (for example, nail clippers and files) should be properly cleaned. Sterilizing equipment before use is especially important when nail tools are shared among a number of people, as is common in commercial nail salons.

Infections of the fingernails or toenails are often characterized by swelling of the surrounding skin, pain in the surrounding area, or thickening of the nail. In some cases, these infections may be serious and need to be treated by a physician.

To help prevent the spread of germs and nail infections:

• Keep nails short and trim them often.
• Scrub the underside of nails with soap and water (or a nail brush) every time you wash your hands.
• Clean any nail grooming tools before use.
• In commercial settings such as nail salons, sterilize nail grooming tools before use.
• Avoid biting or chewing nails.
• Avoid cutting cuticles, as they act as barriers to prevent infection.
• Never rip or bite a hangnail. Instead, clip it with a clean, sanitized nail trimmer.

Clues about your health could be right at your fingertips. Take a look at your nails. They could give insight about possible health concerns.

Many nail changes are normal and nothing to worry about. But sometimes changes in the way your nails look and grow can be a sign of disease. Nails are actually specialized skin cells. They’re made of keratin, a protein also found in your hair and skin.

“Nails aren’t just for appearances,” explains New York University’s Dr. Mayumi Ito, who studies how skin cells regenerate. Your nails protect the ends of your fingers and toes. They also help you grip objects and pick off small things. It would be harder to turn the pages of a book or pick up a thread without fingernails.

The part of the nail you can see is called the nail plate. Nails grow from a region at the base of the nail under the skin called the nail matrix. Here, new nail cells are made and packed together. Older nail cells are then pushed to the surface of the fingertip. Ito was the first to identify the stem cells in the nail matrix that cause nails to grow.

Certain things can affect nail growth. A serious illness or fever can halt the process. The interruption can cause indentations that run horizontally across nails. These are called Beau’s lines. They can also result from injury to the nail, some vitamin deficiencies, and chemotherapy.

Tiny pits in the nail can also be a sign of disease. It’s common among people who have psoriasis. Psoriasis is an autoimmune disease that causes red, scaly patches of skin. Nail pitting is also linked to an autoimmune condition that causes hair loss, called alopecia areata.

If your nails start to scoop inward like a spoon, you may not be getting enough iron. Spoon-shaped nails, or koilonychia, can be a sign of iron-deficiency anemia. Because of a lack of iron, your body can’t make enough of the molecule that red blood cells need to carry oxygen.

Nail clubbing, where the nail tips enlarge and curve around the tip, is another nail problem. It could be a harmless trait that runs in your family. But it’s also linked to lung and heart problems.

Changes in nail color are common. Yellow nails are often caused by nail fungus. In some cases, they can point to something more serious like lung disease.

If you notice your nails have become mostly white, it may just be a sign of aging. But sometimes it’s due to serious conditions like liver and kidney disease or diabetes.

Dark streaks running down the length of the nail that appear suddenly should be checked to rule out skin cancer. Certain infections, especially of the heart, can cause red streaks to appear under the nails.

Talk with your health care provider if your nails start to look abnormal. Your doctor may send you to see a dermatologist. This type of doctor specializes in diseases that affect the skin and nails.

Preventing Nail Problems

• Try not to bite, pick, or tear at your nails.
• Clip hangnails. Be careful not to tear or remove cuticles, as that may lead to an infection.
• Keep your fingernails dry and clean to prevent bacteria from growing under nails.
• Moisturize your nails and cuticles with hand lotion.
• Limit your use of harsh nail care products like nail polish remover.
• Ask your health care provider about medicines that can help with abnormal nails. If you have a nail infection, you may need antifungal or antibacterial drugs.

An inflammatory reaction involving the folds of the skin surrounding the fingernail. It is characterized by acute or chronic purulent, tender, and painful swellings of the tissues around the nail, caused by an abscess of the nail fold. The pathogenic yeast causing paronychia is most frequently Candida albicans. Saprophytic fungi may also be involved. The causative bacteria are usually Staphylococcus, Pseudomonas aeruginosa, or Streptococcus. (Andrews' Diseases of the Skin, 8th ed, p271)

A fungal infection of the nail, usually caused by DERMATOPHYTES; YEASTS; or nondermatophyte MOLDS.

Fungal nail infections are common infections of the fingernails or toenails that can cause the nail to become discolored, thick, and more likely to crack and break. Infections are more common in toenails than fingernails. The technical name for a fungal nail infection is “onychomycosis.”

An ingrown toenail occurs when the side of the nail curls down and grows into the skin around the nail.

Any toe can be affected but it commonly occurs in the big toe.

An ingrown toenail can become painful and inflamed (tender, red and swollen).

Sometimes, it can become infected, which, if left untreated, can spread and infect the underlying bone.

Yellow nail syndrome is a very rare disorder characterized by three features: yellow nail discoloration, respiratory problems, and lower limb swelling (lymphedema). It usually occurs in people over age 50, but can occur in younger people. In addition to being yellow, nails may lack a cuticle, grow very slowly, and become detached (onycholysis). Respiratory problems may include chronic cough, bronchiectasis, and pleural effusion. Chronic sinusitis may also occur.

The cause of yellow nail syndrome remains unknown. It usually occurs on its own, but is sometimes associated with autoimmune disease, lymphatic diseases, or cancers. Some researchers have hypothesized that titanium may play a role in the development of yellow nail syndrome (for example, in dental or joint implants or other environmental exposures).

Treatment addresses each symptom present. In some cases, yellow nail syndrome goes away on its own.

Separation of nail plate from the underlying nail bed. It can be a sign of skin disease, infection (such as ONYCHOMYCOSIS) or tissue injury.

Nail-patella syndrome is characterized by abnormalities of the nails, knees, elbows, and pelvis. The features of nail-patella syndrome vary in severity between affected individuals, even among members of the same family.

Nail abnormalities are seen in almost all individuals with nail-patella syndrome. The nails may be absent or underdeveloped and discolored, split, ridged, or pitted. The fingernails are more likely to be affected than the toenails, and the thumbnails are usually the most severely affected. In many people with this condition, the areas at the base of the nails (lunulae) are triangular instead of the usual crescent shape.

Individuals with nail-patella syndrome also commonly have skeletal abnormalities involving the knees, elbows, and hips. The kneecaps (patellae) are small, irregularly shaped, or absent, and dislocation of the patella is common. Some people with this condition may not be able to fully extend their arms or turn their palms up while keeping their elbows straight. The elbows may also be angled outward (cubitus valgus) or have abnormal webbing. Many individuals with nail-patella syndrome have horn-like outgrowths of the iliac bones of the pelvis (iliac horns). These abnormal projections may be felt through the skin, but they do not cause any symptoms and are usually detected on a pelvic x-ray. Iliac horns are very common in people with nail-patella syndrome and are rarely, if ever, seen in people without this condition.

Other areas of the body may also be affected in nail-patella syndrome, particularly the eyes and kidneys. Individuals with this condition are at risk of developing increased pressure within the eyes (glaucoma) at an early age. Some people develop kidney disease, which can progress to kidney failure.