Eye infections can be caused by bacteria, fungi, or viruses. Learn about the different types, including styes, and their symptoms and treatment.
Eye Infection conjunctivitis
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Eye Infections
Keratoconjunctivitis epidemica 2
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Keratoconjunctivitis epidemica 2
epidemic adenovirus keratoconjunctivitis
Image by Marco Mayer/Wikimedia
Eye Infections
Your eyes can get infections from bacteria, fungi, or viruses. Eye infections can occur in different parts of the eye and can affect just one eye or both. Two common eye infections are
Conjunctivitis - also known as pinkeye. Conjunctivitis is often due to an infection. Children frequently get it, and it is very contagious.
Stye - a bump on the eyelid that happens when bacteria from your skin get into the hair follicle of an eyelash.
Symptoms of eye infections may include redness, itching, swelling, discharge, pain, or problems with vision. Treatment depends on the cause of the infection and may include compresses, eye drops, creams, or antibiotics.
Source: National Eye Institute
Additional Materials (6)
Keratitis - CRASH! Medical Review Series
Video by Paul Bolin, M.D./YouTube
Uveitis - CRASH! Medical Review Series
Video by Paul Bolin, M.D./YouTube
Blocked Tear Ducts in Infants (Pediatric Advice)
Video by paulthomasmd - Dr. Paul/YouTube
New Treatment for Eye Infections
Video by University of Miami Health System/YouTube
Eye Infections - Newborn Care Series
Video by Global Health Media Project/YouTube
Eye Infection conjunctivitis
Eye Infection_conjunctivitis
Image by TheVisualMD
38:20
Keratitis - CRASH! Medical Review Series
Paul Bolin, M.D./YouTube
40:46
Uveitis - CRASH! Medical Review Series
Paul Bolin, M.D./YouTube
4:14
Blocked Tear Ducts in Infants (Pediatric Advice)
paulthomasmd - Dr. Paul/YouTube
1:31
New Treatment for Eye Infections
University of Miami Health System/YouTube
7:54
Eye Infections - Newborn Care Series
Global Health Media Project/YouTube
Eye Infection conjunctivitis
TheVisualMD
Anatomy of the Eye
Sclera (White of the Eye)
Image by agnesliinnea
Sclera (White of the Eye)
Human eye revealing sclera
Image by agnesliinnea
Anatomy and Microbiota of the Eye
Although the eye and skin have distinct anatomy, they are both in direct contact with the external environment. An important component of the eye is the nasolacrimal drainage system, which serves as a conduit for the fluid of the eye, called tears. Tears flow from the external eye to the nasal cavity by the lacrimal apparatus, which is composed of the structures involved in tear production. The lacrimal gland, above the eye, secretes tears to keep the eye moist. There are two small openings, one on the inside edge of the upper eyelid and one on the inside edge of the lower eyelid, near the nose. Each of these openings is called a lacrimal punctum. Together, these lacrimal puncta collect tears from the eye that are then conveyed through lacrimal ducts to a reservoir for tears called the lacrimal sac, also known as the dacrocyst or tear sac.
From the sac, tear fluid flows via a nasolacrimal duct to the inner nose. Each nasolacrimal duct is located underneath the skin and passes through the bones of the face into the nose. Chemicals in tears, such as defensins, lactoferrin, and lysozyme, help to prevent colonization by pathogens. In addition, mucins facilitate removal of microbes from the surface of the eye.
The lacrimal apparatus includes the structures of the eye associated with tear production and drainage. (credit: modification of work by “Evidence Based Medical Educator Inc.”/YouTube)
The surfaces of the eyeball and inner eyelid are mucous membranes called conjunctiva. The normal conjunctival microbiota has not been well characterized, but does exist. One small study (part of the Ocular Microbiome project) found twelve genera that were consistently present in the conjunctiva. These microbes are thought to help defend the membranes against pathogens. However, it is still unclear which microbes may be transient and which may form a stable microbiota.
Use of contact lenses can cause changes in the normal microbiota of the conjunctiva by introducing another surface into the natural anatomy of the eye. Research is currently underway to better understand how contact lenses may impact the normal microbiota and contribute to eye disease.
The watery material inside of the eyeball is called the vitreous humor. Unlike the conjunctiva, it is protected from contact with the environment and is almost always sterile, with no normal microbiota.
Some microbes live on the conjunctiva of the human eye, but the vitreous humor is sterile.
Source: CNX OpenStax
Additional Materials (7)
Illustration of a person cleaning their eyelid with a washcloth
Are your eyelids red, swollen, or itchy? This condition may be the cause.
Image by NIH News in Health
Anatomical features of the tissues surrounding the eye (a) and lacrimal system (b)
Anatomical features of the tissues surrounding the eye (a) and lacrimal system (b)
Image by Cenveo
RHR: The Ocular Microbiome, with Dr. Harvey Fishman
Video by Chris Kresser, L.Ac/YouTube
Eye Anatomy Chapter 2 : The Conjunctiva 1
Video by Evidence Based Medical Educator Inc./YouTube
Eye Anatomy Chapter 3 : The Conjunctiva 2
Video by Evidence Based Medical Educator Inc./YouTube
The Human Eye
Video by 7activestudio/YouTube
Pterygium, carnosidad, conjunctival autograft, conjunctiva - A State of Sight #10
Video by eyePorter/YouTube
Illustration of a person cleaning their eyelid with a washcloth
NIH News in Health
Anatomical features of the tissues surrounding the eye (a) and lacrimal system (b)
Cenveo
46:04
RHR: The Ocular Microbiome, with Dr. Harvey Fishman
Chris Kresser, L.Ac/YouTube
1:06
Eye Anatomy Chapter 2 : The Conjunctiva 1
Evidence Based Medical Educator Inc./YouTube
0:53
Eye Anatomy Chapter 3 : The Conjunctiva 2
Evidence Based Medical Educator Inc./YouTube
6:20
The Human Eye
7activestudio/YouTube
2:54
Pterygium, carnosidad, conjunctival autograft, conjunctiva - A State of Sight #10
eyePorter/YouTube
Infections of the Eye
Eye Infection conjunctivitis
Image by TheVisualMD
Eye Infection conjunctivitis
Eye Infection_conjunctivitis
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Infections of the Eye
The conjunctiva is a frequent site of infection of the eye; like other mucous membranes, it is also a common portal of entry for pathogens. Inflammation of the conjunctiva is called conjunctivitis, although it is commonly known as pinkeye because of the pink appearance in the eye. Infections of deeper structures, beneath the cornea, are less common. Conjunctivitis occurs in multiple forms. It may be acute or chronic. Acute purulent conjunctivitis is associated with pus formation, while acute hemorrhagic conjunctivitis is associated with bleeding in the conjunctiva. The term blepharitis refers to an inflammation of the eyelids, while keratitis refers to an inflammation of the cornea; keratoconjunctivitis is an inflammation of both the cornea and the conjunctiva, and dacryocystitis is an inflammation of the lacrimal sac that can often occur when a nasolacrimal duct is blocked.
(a) Conjunctivitis is inflammation of the conjunctiva. (b) Blepharitis is inflammation of the eyelids. (c) Keratitis is inflammation of the cornea. (credit a: modification of work by Lopez-Prats MJ, Sanz Marco E, Hidalgo-Mora JJ, Garcia-Delpech S, Diaz-Llopis M; credit b, c: modification of work by Centers for Disease Control and Prevention)
Infections leading to conjunctivitis, blepharitis, keratoconjunctivitis, or dacryocystitis may be caused by bacteria or viruses, but allergens, pollutants, or chemicals can also irritate the eye and cause inflammation of various structures. Viral infection is a more likely cause of conjunctivitis in cases with symptoms such as fever and watery discharge that occurs with upper respiratory infection and itchy eyes. The table below summarizes some common forms of conjunctivitis and blepharitis.
Types of Conjunctivities and Blepharitis
Condition
Description
Causative Agent(s)
Acute purulent conjunctivitis
Conjunctivitis with purulent discharge
Bacterial (Haemophilus, Staphylococcus)
Acute hemorrhagic conjunctivitis
Involves subconjunctival hemorrhages
Viral (Picornaviradae)
Acute ulcerative blepharitis
Infection involving eyelids; pustules and ulcers may develop
Bacterial (Staphylococcal) or viral (herpes simplex, varicella-zoster, etc.)
Follicular conjunctivitis
Inflammation of the conjunctiva with nodules (dome-shaped structures that are red at the base and pale on top)
Viral (adenovirus and others); environmental irritants
Dacryocystitis
Inflammation of the lacrimal sac often associated with a plugged nasolacrimal duct
Bacterial, viral, or protozoal; environmental irritants
Keratoconjunctivitis
Inflammation of cornea and conjunctiva
Bacterial, viral (adenoviruses), or other causes (including dryness of the eye)
Nonulcerative blepharitis
Inflammation, irritation, redness of the eyelids without ulceration
Environmental irritants; allergens
Papillary conjunctivitis
Inflammation of the conjunctiva; nodules and papillae with red tops develop
Environmental irritants; allergens
Source: CNX OpenStax
Additional Materials (3)
Procedure of conjunctival swabs
(a) The virus COVID-19 (SARS-CoV-2) containing single-stranded (positive-sense) RNA associated with a nucleoprotein within a capsid comprised of matrix protein, (b) conjunctival swabs performed in personal protective equipment, (c) swabs of both eyes were taken by rolling cotton swabs across the lower fornix conjunctiva of both eyes, (d) both swabs, one for each eye, were introduced in the same virus-specific tube and delivered to the laboratory for analysis (e).
Image by Maria Cristina Savastano et al./Wikimedia
Stye on the lower eyelid
Image by Bluec/Wikimedia
Mayo Clinic Minute: What parents need to know about pink eye
Video by Mayo Clinic/YouTube
Procedure of conjunctival swabs
Maria Cristina Savastano et al./Wikimedia
Stye on the lower eyelid
Bluec/Wikimedia
1:00
Mayo Clinic Minute: What parents need to know about pink eye
Mayo Clinic/YouTube
Bacterial Infections
Preventing Conjunctivitis
Image by Raimundo Pastor
Preventing Conjunctivitis
Conjunctivitis in the left eye.
Image by Raimundo Pastor
Bacterial Infections of the Eyes
A number of bacteria are able to cause infection when introduced to the mucosa of the eye. In general, bacterial eye infections can lead to inflammation, irritation, and discharge, but they vary in severity. Some are typically short-lived, and others can become chronic and lead to permanent eye damage. Prevention requires limiting exposure to contagious pathogens. When infections do occur, prompt treatment with antibiotics can often limit or prevent permanent damage. The table below summarizes the characteristics of some common bacterial infections of the eyes.
Source: CNX OpenStax
Additional Materials (4)
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Conjunctivitis (Pink Eye) in Newborns
This was a newborn with gonococcal ophthalmia neonatorum caused by a maternally transmitted gonococcal infection. Unless preventative measures are taken, it is estimated that gonococcal ophthalmia neonatorum will develop in 28% of infants born to women with gonorrhea. It affects the corneal epithelium causing microbial keratitis, ulceration and perforation.
Image by CDC / J. Pledger
Conjunctivitis - What is pink eye? (NEI)
Swollen eye with conjunctivitis: A swollen, pus-filled eye with conjunctivitis.
Image by Tanalai
Example of conjunctivitis
Several pictures of the same eye affected by conjunctivitis.
Image by No machine-readable author provided. Herakrieger assumed (based on copyright claims)./Wikimedia
1) Normal Eye
2) Conjunctivitis - INFLAMMATION of the CONJUNCTIVA.
Interactive by TheVisualMD
Bacterial Conjunctivitis
Like the skin, the surface of the eye comes in contact with the outside world and is somewhat prone to infection by bacteria in the environment. Bacterial conjunctivitis (pinkeye) is a condition characterized by inflammation of the conjunctiva, often accompanied by a discharge of sticky fluid (described as acute purulent conjunctivitis) Conjunctivitis can affect one eye or both, and it usually does not affect vision permanently. Bacterial conjunctivitis is most commonly caused by Haemophilusinfluenzae, but can also be caused by other species such as Moraxella catarrhalis, S. pneumoniae, and S. aureus. The causative agent may be identified using bacterial cultures, Gram stain, and diagnostic biochemical, antigenic, or nucleic acid profile tests of the isolated pathogen. Bacterial conjunctivitis is very contagious, being transmitted via secretions from infected individuals, but it is also self-limiting. Bacterial conjunctivitis usually resolves in a few days, but topical antibiotics are sometimes prescribed. Because this condition is so contagious, medical attention is recommended whenever it is suspected. Individuals who use contact lenses should discontinue their use when conjunctivitis is suspected. Certain symptoms, such as blurred vision, eye pain, and light sensitivity, can be associated with serious conditions and require medical attention.
Acute, purulent, bacterial conjunctivitis causes swelling and redness in the conjunctiva, the membrane lining the whites of the eyes and the inner eyelids. It is often accompanied by a yellow, green, or white discharge, which can dry and become encrusted on the eyelashes. (credit: “Tanalai”/Wikimedia Commons)
Neonatal Conjunctivitis
Newborns whose mothers have certain sexually transmitted infections are at risk of contracting ophthalmia neonatorum or inclusion conjunctivitis, which are two forms of neonatal conjunctivitis contracted through exposure to pathogens during passage through the birth canal. Gonococcal ophthalmia neonatorum is caused by Neisseria gonorrhoeae, the bacterium that causes the STD gonorrhea. Inclusion (chlamydial) conjunctivitis is caused by Chlamydia trachomatis, the anaerobic, obligate, intracellular parasite that causes the STD chlamydia.
To prevent gonoccocal ophthalmia neonatorum, silver nitrate ointments were once routinely applied to all infants’ eyes shortly after birth; however, it is now more common to apply antibacterial creams or drops, such as erythromycin. Most hospitals are required by law to provide this preventative treatment to all infants, because conjunctivitis caused by N. gonorrhoeae, C. trachomatis, or other bacteria acquired during a vaginal delivery can have serious complications. If untreated, the infection can spread to the cornea, resulting in ulceration or perforation that can cause vision loss or even permanent blindness. As such, neonatal conjunctivitis is treated aggressively with oral or intravenous antibiotics to stop the spread of the infection. Causative agents of inclusion conjunctivitis may be identified using bacterial cultures, Gram stain, and diagnostic biochemical, antigenic, or nucleic acid profile tests.
A newborn suffering from gonoccocal opthalmia neonatorum. Left untreated, purulent discharge can scar the cornea, causing loss of vision or permanent blindness. (credit: Centers for Disease Control and Prevention)
Source: CNX OpenStax
Additional Materials (4)
Healthy Eye / Infected Eye
Healthy vs Infected Eye
Pink eye is extremely common. People often call conjunctivitis “pink eye” because it can cause the white of the eye to take on a pink or red color. Symptoms of pink eye can vary but typically include redness or swelling of the white of the eye.
Interactive by Centers for Disease Control and Prevention (CDC)
Conjunctivitis (Pinkeye)
Allergic Conjunctivitis
Image by BruceBlaus
Help protect yourself from getting and spreading Pink Eye (conjunctivitis)
Help protect yourself from getting and spreading Pink Eye (conjunctivitis)
Image by CDC
Conjunctivitis, pink eye, virus or bacteria, eye infection - A State of Sight #35
Video by eyePorter/YouTube
Healthy vs Infected Eye
Centers for Disease Control and Prevention (CDC)
Conjunctivitis (Pinkeye)
BruceBlaus
Help protect yourself from getting and spreading Pink Eye (conjunctivitis)
CDC
3:07
Conjunctivitis, pink eye, virus or bacteria, eye infection - A State of Sight #35
eyePorter/YouTube
Trachoma
Chlamydia trachomatis
Image by CDC/ Dr. E. Arum, Dr. N. Jacobs
Chlamydia trachomatis
Under a magnification of 50X, this photomicrograph reveals a McCoy cell monolayer culture, and that some of the cells exhibited Chlamydia trachomatis inclusion bodies. The intracellular inclusion body represents the replication phase of the Chlamydia spp. organisms, whereupon, the reorganized reticulate body (RB) multiplies through binary fission into 100-500 new RBs, which mature into elementary bodies (EB). Chlamydia, caused by Chlamydia trachomatis, is the most common bacterial sexually transmitted infection. Using cell cultures from the McCoy cell line is one methods implemented in diagnosing Chlamydia infections.
Image by CDC/ Dr. E. Arum, Dr. N. Jacobs
Bacterial Conjunctivitis: Trachoma
Trachoma, or granular conjunctivitis, is a common cause of preventable blindness that is rare in the United States but widespread in developing countries, especially in Africa and Asia. The condition is caused by the same species that causes neonatal inclusion conjunctivitis in infants, Chlamydia trachomatis. C. trachomatis can be transmitted easily through fomites such as contaminated towels, bed linens, and clothing and also by direct contact with infected individuals. C. trachomatis can also be spread by flies that transfer infected mucous containing C. trachomatis from one human to another.
Infection by C. trachomatis causes chronic conjunctivitis, which leads to the formation of necrotic follicles and scarring in the upper eyelid. The scars turn the eyelashes inward (a condition known as trichiasis) and mechanical abrasion of the cornea leads to blindness. Antibiotics such as azithromycin are effective in treating trachoma, and outcomes are good when the disease is treated promptly. In areas where this disease is common, large public health efforts are focused on reducing transmission by teaching people how to avoid the risks of the infection.
(a) If trachoma is not treated early with antibiotics, scarring on the eyelid can lead to trichiasis, a condition in which the eyelashes turn inward. (b) Trichiasis leads to blindness if not corrected by surgery, as shown here. (credit b: modification of work by Otis Historical Archives National Museum of Health & Medicine)
Source: CNX OpenStax
Additional Materials (5)
An illustration depicting pink eye
An illustration depicting pink eye
Image by BruceBlaus
Healthy vs Infected Eye
Image by Centers for Disease Control and Prevention (CDC)
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Chlamydia infections
Conjunctivitis due to chlamydia.
Image by SOA-AIDS Amsterdam
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Trachoma
Entropion and trichiasis secondary to trachoma. Trachoma stage IV. Conjunctivitis, keratitis. Surgical repair of in-turned eyelid and eyelashes resulting from trachoma
Image by Otis Historical Archives Nat'l Museum of Health & Medicine
Trachoma Conjunctivitis
Video by DrER.tv/YouTube
An illustration depicting pink eye
BruceBlaus
Healthy vs Infected Eye
Centers for Disease Control and Prevention (CDC)
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Chlamydia infections
SOA-AIDS Amsterdam
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Trachoma
Otis Historical Archives Nat'l Museum of Health & Medicine
3:31
Trachoma Conjunctivitis
DrER.tv/YouTube
Keratitis
Adenoviral keratitis of a 24 years old girl
Image by Imrankabirhossain
Adenoviral keratitis of a 24 years old girl
Adenoviral keratitis of a 24 years old girl
Image by Imrankabirhossain
Bacterial Keratitis
Keratitis can have many causes, but bacterial keratitis is most frequently caused by Staphylococcus epidermidis and/or Pseudomonas aeruginosa. Contact lens users are particularly at risk for such an infection because S. epidermidis and P. aeruginosa both adhere well to the surface of the lenses. Risk of infection can be greatly reduced by proper care of contact lenses and avoiding wearing lenses overnight. Because the infection can quickly lead to blindness, prompt and aggressive treatment with antibiotics is important. The causative agent may be identified using bacterial cultures, Gram stain, and diagnostic biochemical, antigenic, or nucleic acid profile tests of the isolated pathogen.
Source: CNX OpenStax
Additional Materials (3)
Keratitis
Subepithelial corneal infiltrates in epidemic keratoconjunctivitis
Image by Imrankabirhossain
Keratitis
Dendritic corneal ulcer after fluorescein staining under cobalt blue illumination
Image by Imrankabirhossain
Keratitis - Bacterial and Fungal
Video by Wills Eye Hospital/YouTube
Keratitis
Imrankabirhossain
Keratitis
Imrankabirhossain
3:50
Keratitis - Bacterial and Fungal
Wills Eye Hospital/YouTube
Biofilms
5 stages of biofilm development
Image by D. Davis
5 stages of biofilm development
Stage 1, initial attachment; stage 2, irreversible attachment; stage 3, maturation I; stage 4, maturation II; stage 5, dispersion. Each stage of development in the diagram is paired with a photomicrograph of a developing Pseudomonas aeruginosa biofilm. All photomicrographs are shown to same scale
Image by D. Davis
Biofilms and Infections of the Skin and Eyes
When treating bacterial infections of the skin and eyes, it is important to consider that few such infections can be attributed to a single pathogen. While biofilms may develop in other parts of the body, they are especially relevant to skin infections (such as those caused by S. aureus or P. aeruginosa) because of their prevalence in chronic skin wounds. Biofilms develop when bacteria (and sometimes fungi) attach to a surface and produce extracellular polymeric substances (EPS) in which cells of multiple organisms may be embedded. When a biofilm develops on a wound, it may interfere with the natural healing process as well as diagnosis and treatment.
Because biofilms vary in composition and are difficult to replicate in the lab, they are still not thoroughly understood. The extracellular matrix of a biofilm consists of polymers such as polysaccharides, extracellular DNA, proteins, and lipids, but the exact makeup varies. The organisms living within the extracellular matrix may include familiar pathogens as well as other bacteria that do not grow well in cultures (such as numerous obligate anaerobes). This presents challenges when culturing samples from infections that involve a biofilm. Because only some species grow in vitro, the culture may contain only a subset of the bacterial species involved in the infection.
Biofilms confer many advantages to the resident bacteria. For example, biofilms can facilitate attachment to surfaces on or in the host organism (such as wounds), inhibit phagocytosis, prevent the invasion of neutrophils, and sequester host antibodies. Additionally, biofilms can provide a level of antibiotic resistance not found in the isolated cells and colonies that are typical of laboratory cultures. The extracellular matrix provides a physical barrier to antibiotics, shielding the target cells from exposure. Moreover, cells within a biofilm may differentiate to create subpopulations of dormant cells called persister cells. Nutrient limitations deep within a biofilm add another level of resistance, as stress responses can slow metabolism and increase drug resistance.
Source: CNX OpenStax
Additional Materials (4)
Biofilm components in streams
An idealized scheme of the biofilm components in streams
The different biofilm components (algae and bacteria, as the principals) are embedded in an exopolysaccharide matrix (EPS), and are net receptors of inorganic and organic elements and remain submitted to the influences of the different environmental factors.
Image by Sergi Sabater, Xisca Timoner, Carles Borrego and Vicenç Acuña/Wikimedia
Biofilm lifecycle
Biofilm lifecycle, Review of Pseudomonas Attachment and Biofilm Formation in Food Industry. Poult Fish Wildl Sci 3:126
Légende : QS=Quorum sensing ; EPS=extracellular polymeric substance
Image by Salsero35/Wikimedia
Mature biofilm structure
Mature biofilm structureBiofilm is characterized by heterogenous environment and the presence of a variety of subpopulations. A biofilm structure is composed of metabolically active (both resistant and tolerant) and non-active cells (viable but not culturable cells, VBNC, and persisters) as well as polymer matrix consisting of polysaccharide, extracellular DNA and proteins. Biofilm growth is associated with an escalated level of mutations and horizontal gene transfer (HGT) which is promoted in due to the packed and dense structure. Bacteria in biofilms communicate by QS, which activates genes participating in virulence factors production (modified from Hall and Mah).
Hall, C.W. and Mah, T.F. (2017) "Molecular mechanisms of biofilm-based antibiotic resistance and tolerance in pathogenic bacteria". FEMS Microbiol. Rev. 41: 276–301
Image by Aleksandra Rapacka-Zdonczyk, Agata Wozniak, Joanna Nakonieczna and Mariusz Grinholc/Wikimedia
What Are Bacterial Biofilms? A Six Minute Montage
Video by biofilm/YouTube
Biofilm components in streams
Sergi Sabater, Xisca Timoner, Carles Borrego and Vicenç Acuña/Wikimedia
Biofilm lifecycle
Salsero35/Wikimedia
Mature biofilm structure
Aleksandra Rapacka-Zdonczyk, Agata Wozniak, Joanna Nakonieczna and Mariusz Grinholc/Wikimedia
6:00
What Are Bacterial Biofilms? A Six Minute Montage
biofilm/YouTube
Viral Infections
Viral conjunctivitis - Conjunctivitis disease
Image by Banswalhemant/Wikimedia
Viral conjunctivitis - Conjunctivitis disease
Inflammation or infection of the outer membrane of the eyeball and the inner eyelid.
Image by Banswalhemant/Wikimedia
Viral Infections of the Skin and Eyes
A number of viruses can cause infections via direct contact with skin and eyes, causing signs and symptoms ranging from rashes and lesions to warts and conjunctivitis. All of these viral diseases are contagious, and while some are more common in children (fifth disease and roseola), others are prevalent in people of all ages (oral herpes, viral conjunctivitis, papillomas). In general, the best means of prevention is avoiding contact with infected individuals. Treatment may require antiviral medications; however, several of these conditions are mild and typically resolve without treatment. Table below summarizes the characteristics of some common viral infections of the skin and eyes.
Source: CNX OpenStax
Additional Materials (13)
Bacterial and Viral Conjunctivitis
Video by Maureen Richards Immunology & Microbiology/YouTube
What is Roseola? (A Common Viral Infection)
Video by healthery/YouTube
What is Fifth Disease ? Fifth Disease Causes, Sign Symptoms, Treatment
Video by New Medical Imaging/YouTube
The Basics: Roseola | WebMD
Video by WebMD/YouTube
Slapped Cheek Syndrome (Fifth Disease) in Babies and Toddlers
Video by FirstCry Parenting/YouTube
Roseola Infantum!
Video by How To Gastro/YouTube
fifth disease - child with rash
Video by DrER.tv/YouTube
fifth disease - patient education video
Video by DrER.tv/YouTube
Fifth Disease - Akron Children's Hospital video
Video by AkronChildrens/YouTube
Fifth Disease or Erythema Infectiosum
Video by Larry Mellick/YouTube
Fifth Disease
Video by Naperville Community Television NCTV17/YouTube
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HHV-6
An electron micrograph of HHV-6 also includes a labeled insert of the mature virus particle. The HHV-6 is a double stranded DNA virus of the herpes family. The virus particles shown here have matured and are then released from the lymphocyte which has been infected. The "owl's eye" appearance of the virus particles is characteristic of the herpes family. The HHV-6, or the human herpes virus-6, was thought to infect b-cells and was at one time called HBLV, human b-lymphotropic virus. It is now known to infect t-cells and is the cause of the childhood rash "roseola" and some cases of mononucleosis.
Image by Laboratory Of Tumor Cell Biology / Bernard Kramarsky (Photographer)
What is Fifth Disease ? Fifth Disease Causes, Sign Symptoms, Treatment
New Medical Imaging/YouTube
1:01
The Basics: Roseola | WebMD
WebMD/YouTube
2:40
Slapped Cheek Syndrome (Fifth Disease) in Babies and Toddlers
FirstCry Parenting/YouTube
6:40
Roseola Infantum!
How To Gastro/YouTube
2:12
fifth disease - child with rash
DrER.tv/YouTube
5:36
fifth disease - patient education video
DrER.tv/YouTube
3:23
Fifth Disease - Akron Children's Hospital video
AkronChildrens/YouTube
2:14
Fifth Disease or Erythema Infectiosum
Larry Mellick/YouTube
1:00
Fifth Disease
Naperville Community Television NCTV17/YouTube
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HHV-6
Laboratory Of Tumor Cell Biology / Bernard Kramarsky (Photographer)
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Roseola
CDC
Parasitic Infections
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Acanthamoeba keratitis
Image by Author Jacob Lorenzo-Morales, Naveed A. Khan and Julia Walochnik
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Acanthamoeba keratitis
Corneal melting and vascularization in a patient with Acanthamoeba keratitis
Date
Image by Author Jacob Lorenzo-Morales, Naveed A. Khan and Julia Walochnik
Protozoan and Helminthic Infections of the Skin and Eyes
Many parasitic protozoans and helminths use the skin or eyes as a portal of entry. Some may physically burrow into the skin or the mucosa of the eye; others breach the skin barrier by means of an insect bite. Still others take advantage of a wound to bypass the skin barrier and enter the body, much like other opportunistic pathogens. Although many parasites enter the body through the skin, in this chapter we will limit our discussion to those for which the skin or eyes are the primary site of infection. Parasites that enter through the skin but travel to a different site of infection will be covered in other chapters. In addition, we will limit our discussion to microscopic parasitic infections of the skin and eyes. Macroscopic parasites such as lice, scabies, mites, and ticks are beyond the scope of this text.
Acanthamoeba Infections
Acanthamoeba is a genus of free-living protozoan amoebae that are common in soils and unchlorinated bodies of fresh water. (This is one reason why some swimming pools are treated with chlorine.) The genus contains a few parasitic species, some of which can cause infections of the eyes, skin, and nervous system. Such infections can sometimes travel and affect other body systems. Skin infections may manifest as abscesses, ulcers, and nodules. When acanthamoebae infect the eye, causing inflammation of the cornea, the condition is called Acanthamoeba keratitis.
While Acanthamoeba keratitis is initially mild, it can lead to severe corneal damage, vision impairment, or even blindness if left untreated. Similar to eye infections involving P. aeruginosa, Acanthamoeba poses a much greater risk to wearers of contact lensesbecause the amoeba can thrive in the space between contact lenses and the cornea. Prevention through proper contact lens care is important. Lenses should always be properly disinfected prior to use, and should never be worn while swimming or using a hot tub.
Acanthamoeba can also enter the body through other pathways, including skin wounds and the respiratory tract. It usually does not cause disease except in immunocompromised individuals; however, in rare cases, the infection can spread to the nervous system, resulting in a usually fatal condition called granulomatous amoebic encephalitis (GAE). Disseminated infections, lesions, and Acanthamoeba keratitis can be diagnosed by observing symptoms and examining patient samples under the microscope to view the parasite. Skin biopsies may be used.
Acanthamoeba keratitis is difficult to treat, and prompt treatment is necessary to prevent the condition from progressing. The condition generally requires three to four weeks of intensive treatment to resolve. Common treatments include topical antiseptics (e.g., polyhexamethylene biguanide, chlorhexidine, or both), sometimes with painkillers or corticosteroids (although the latter are controversial because they suppress the immune system, which can worsen the infection). Azoles are sometimes prescribed as well. Advanced cases of keratitis may require a corneal transplant to prevent blindness.
Acanthamoeba spp. are waterborne parasites very common in unchlorinated aqueous environments. As shown in this life cycle, Acanthamoeba cysts and trophozoites are both capable of entering the body through various routes, causing infections of the eye, skin, and central nervous system. (credit: modification of work by Centers for Disease Control and Prevention)(a) An Acanthamoeba cyst. (b) An Acanthamoeba trophozoite (c) The eye of a patient with Acanthamoeba keratitis. The fluorescent color, which is due to sodium fluorescein application, highlights significant damage to the cornea and vascularization of the surrounding conjunctiva. (credit a: modification of work by Centers for Disease Control and Prevention; credit b, c: modification of work by Jacob Lorenzo-Morales, Naveed A Kahn and Julia Walochnik)
Loiasis
The helminth Loa loa, also known as the African eye worm, is a nematode that can cause loiasis, a disease endemic to West and Central Africa. The disease does not occur outside that region except when carried by travelers. There is evidence that individual genetic differences affect susceptibility to developing loiasis after infection by the Loa loa worm. Even in areas in which Loa loa worms are common, the disease is generally found in less than 30% of the population. It has been suggested that travelers who spend time in the region may be somewhat more susceptible to developing symptoms than the native population, and the presentation of infection may differ.
The parasite is spread by deerflies (genus Chrysops), which can ingest the larvae from an infected human via a blood meal. When the deerfly bites other humans, it deposits the larvae into their bloodstreams. After about five months in the human body, some larvae develop into adult worms, which can grow to several centimeters in length and live for years in the subcutaneous tissue of the host.
The name “eye worm” alludes to the visible migration of worms across the conjunctiva of the eye. Adult worms live in the subcutaneous tissues and can travel at about 1 cm per hour. They can often be observed when migrating through the eye, and sometimes under the skin; in fact, this is generally how the disease is diagnosed. It is also possible to test for antibodies, but the presence of antibodies does not necessarily indicate a current infection; it only means that the individual was exposed at some time. Some patients are asymptomatic, but in others the migrating worms can cause fever and areas of allergic inflammation known as Calabar swellings. Worms migrating through the conjunctiva can cause temporary eye pain and itching, but generally there is no lasting damage to the eye. Some patients experience a range of other symptoms, such as widespread itching, hives, and joint and muscle pain.
Worms can be surgically removed from the eye or the skin, but this treatment only relieves discomfort; it does not cure the infection, which involves many worms. The preferred treatment is diethylcarbamazine, but this medication produces severe side effects in some individuals, such as brain inflammation and possible death in patients with heavy infections. Albendazole is also sometimes used if diethylcarbamazine is not appropriate or not successful. If left untreated for many years, loiasis can damage the kidneys, heart, and lungs, though these symptoms are rare.
This Loa loa worm, measuring about 55 mm long, was extracted from the conjunctiva of a patient with loiasis. The Loa loa has a complex life cycle. Biting deerflies native to the rain forests of Central and West Africa transmit the larvae between humans. (credit a: modification of work by Eballe AO, Epée E, Koki G, Owono D, Mvogo CE, Bella AL; credit b: modification of work by NIAID; credit c: modification of work by Centers for Disease Control and Prevention)
Parasitic Skin and Eye Infections
The protozoan Acanthamoeba and the helminth Loa loa are two parasites capable of causing infections of the skin and eyes. The table below summarizes the characteristics of some common fungal infections of the skin.
Source: CNX OpenStax
Additional Materials (8)
Parasitic Diseases Lectures #30: Loiasis
Video by Parasites Without Borders/YouTube
Protect Your Eyes: Te’s Story—Don’t Sleep in Contacts
Video by Centers for Disease Control and Prevention (CDC)/YouTube
Protect Your Eyes: Whitney’s Story— Keep Water Away from Contacts
Video by Centers for Disease Control and Prevention (CDC)/YouTube
Scientists Shocked By Worms Breeding Inside People's Eyes
Video by The Infographics Show/YouTube
Acanthamoeba polyphaga protozoan
This scanning electron microscopic (SEM) image revealed some of the ultrastructural features on the surface of an Acanthamoeba polyphaga protozoan. Note the numerous pseudopodia, projecting from the organism’s surface. These enable the amoeba to move about, and grasp objects in its environment.
Image by CDC/ Catherine Armbruster; Margaret Williams; Photo credit: Janice Haney Carr
Patient stories: Ian West - acanthamoeba keratitis
Video by Optometry Today/YouTube
18:39
Parasitic Diseases Lectures #30: Loiasis
Parasites Without Borders/YouTube
2:53
Protect Your Eyes: Te’s Story—Don’t Sleep in Contacts
Centers for Disease Control and Prevention (CDC)/YouTube