An Overview of Epidemic Keratoconjunctivitis

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Epidemic keratoconjunctivitis (EKC), also known as adenoviral keratoconjunctivitis or keratoconjunctivitis epidemica, is a highly contagious eye infection that affects both the cornea (the clear front surface of the eye) and the conjunctiva (the white of the eye). Inflammation of the cornea only is called keratitis, while inflammation of the conjunctiva only is called conjunctivitis (or "pink eye").

EKC is caused by a family of viruses known as adenoviruses that are responsible for an array of respiratory, gastrointestinal, and eye infections. EKC can usually be diagnosed by the red and swollen appearance of the eye, although there are newer tests able to detect the virus by taking a swab of eye fluid.

Although there are no antiviral drugs known to effectively treat EKC, although certain eye drops and topical agents may provide some relief. Proper handwashing and the avoidance of people with EKC symptoms can help prevent the spread of the virus.

Symptoms 

Before the onset of eye symptoms, EKC will usually manifest with flu-like symptoms, including fever, muscle aches, malaise, and swollen lymph nodes. When eye symptoms do develop, they typically occur in phases.

The early acute phase, spanning seven to 10 days of the first appearance of symptoms, is characterized by inflammation of the conjunctiva with or without the involvement of the cornea.

The later chronic stage is defined by subepithelial corneal infiltrates, a condition in which the immune system inadvertently draws white blood cells into the vessels of the cornea. This can lead to corneal opacity (mild scarring of the cornea), which can interfere with vision but usually leaves no permanent damage.

The symptoms of EKC frequently include:

  • Eye redness
  • Eye soreness and irritation
  • A gritty feeling in the eye
  • Swelling of the conjunctivitis
  • Excessive tearing
  • Eye crusting, especially when waking up
  • Swelling of the eyelid
  • Blurring of vision
  • Photophobia (sensitivity to light)
  • A greyish-white clouding of the cornea

Although EKC usually starts in one eye, around 70% of people will eventually develop in both eyes (usually because they've wiped the infected eye and touched the other with the same hand).

Complications

Though EKC usually only causes temporary corneal opacity, severe or prolonged infections can cause permanent scarring of the cornea, resulting in vision loss and blindness.

Prolonged infections can also cause scarring of the symblepharon formation (where the eyeball meets the eyelid). Scarring of this structure can cause discomfort when blinking, impair teardrop production, and lead to keratoconjunctivitis sicca (dry eye syndrome).

Causes

EKC can be caused by many different types of adenovirus. Adenoviruses are a hearty family of viruses that are able to survive outside of the body for a prolonged period of time (up to 30 days in some cases).

Adenoviruses thrive in the eyes, nasal passages, saliva, and respiratory tract. Their thick protein shells (called capsids) are resistant to adverse environmental conditions, allowing them to be spread from person to person or to be aerosolized in water droplets whenever a person sneezes.

Some of the possible modes of transmission include:

  • Direct contact with infected teardrops or nasal secretions
  • Hand-to-eye contact with infected surfaces
  • Being touched by an infected individual
  • Sneezing or coughing (particularly in closed spaces)
  • Shared personal care items (like eyelash brushes)
  • Shared sunglasses

EKC infections tend to occur in clusters, particularly in closed institutions such as schools, daycare centers, hospitals, nursing homes, and workplaces.

The incubation period—the time from exposure to symptoms—can last from two to 14 days. EKC infections are by far the most contagious during the first few days of symptoms but can remain so for up to two weeks.

Adenovirus particles can remain on surfaces for more than one month and cause reinfection until the surfaces are properly sanitized.

Diagnosis

EKC can usually be diagnosed with a simple eye exam. A lighted scope, called an ophthalmoscope, can check for characteristic signs of EKC, such as corneal opacity and subepithelial infiltrates. The doctor may also check for swollen lymph nodes in the neck.

A lighted magnifying device, called a slit lamp, may be used to check the back of the eye if the symptoms are severe or persistent.

In most cases, treatment would begin if the symptoms are uncomplicated. If the diagnosis is uncertain or the presentation of symptoms are unusual, the doctor can use a simple, in-office test to detect the presence of adenovirus in the eye.

Adenovirus Swab Test

Adenovirus swab tests are highly sensitive rapid tests that can confirm an adenovirus infection within around 10 minutes. Available under such brand names as RP Adeno Detector and AdenoPlus, the test involves running a soft swab between the lower eyelid and conjunctiva to obtain a sample of fluid.

Newer-generation swab tests have a sensitivity of between 95.5% to 98% and a specificity of between 39.5% and 85%. Because of the low specificity, there is a risk of a false-positive result.

The swab test is non-invasive but may cause discomfort. An anesthetic eyedrop may be used for people who dislike having their eyeballs touched.

Adenovirus swab tests should ideally be done within the first seven days of the appearance of symptoms to ensure the most accurate results.

Treatment

EKC infections usually resolve on their own without treatment. At present, there are no oral or topical drugs able to clear the infection. Treatment is primarily focused on the relief of symptoms and the prevention of complications.

Among some of the more common treatment options:

  • Cold compresses can help reduce eye swelling and discomfort.
  • Artificial tears can help keep eyes hydrated and reduce grittiness.
  • Vasoconstrictor eye drops are intended for the short-term treatment of eye redness. Overuse can cause rebound redness.
  • Cyclosporine eye drops, which suppress the immune system, can help treat persistent corneal opacity,
  • Cycloplegic eye drops, like Atropen (atropin), can temporarily dilate the pupils in people with severe photophobia.
  • Corticosteroid eye drops are often used in severe EKC infections. Though able to reduce inflammation quickly, they may actually end up prolonging the infection.

Prevention

EKC is a highly contagious disease and one that requires vigilance to prevent further spread of the infection. Children with EKC should stay home from school until symptoms have resolved. Adults can continue to go to work as long as they continue to adhere to infection control measures.

To avoid getting or spreading EKC during an outbreak:

  • Avoid touching your eyes. If you do so, wash your hands thoroughly with soap and warm water or an alcohol-based hand sanitizer.
  • Avoid touching others. This is especially true in places where outbreaks are common, such as daycare or nursing homes.
  • Do not share makeup or towels. Anything that comes into contact with your eyes should not be used by anyone else (or vice versa).
  • Cover your mouth when you cough or sneeze. To keep your hands clean, cough or sneeze into the crook of your elbow rather than into your hands.
  • Use separate towels for family members. Moreover, until the outbreak is passed, try to wash towels and facecloths as frequently as possible.
  • Use disposable tissues to blow your nose. When finished, throw them away immediately.
  • Keep surfaces clean. This is especially true in the bathroom where infections commonly spread. Leave an antibacterial cleaner or wipes in the bathroom so that family members can clean up after themselves.
  • Wear an eyepatch. If you have to go to work and want to avoid touching your eye, ask your doctor or pharmacist about an eyepatch. Find one that cups the eye softly rather than lying flat against it.

There is some evidence that Betadine (povidone-iodine) eye drops can reduce the infectivity of the virus, reducing the risk of EKC transmission.

A Word From Verywell

Epidemic keratoconjunctivitis is a highly contagious infection that is easily spread unless good hygiene and infection control practices are maintained. If you or a family member gets EKC, don't assume that you can skip seeing a doctor because there is "nothing you can do about it." There may be other explanations for your symptoms, some of which may treatable.

Even if it is EKC, it's worth having your doctor look it to avoid complications and prescribed preventative treatments if necessary. This is especially true for infants and the elderly in whom EKG complications may turn severe.

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