What is Vernal Keratoconjunctivitis?
Vernal keratoconjunctivitis (VKC) is a repeated inflammation of the inner surface of the eyelid that can affect both eyes due to allergies. Its flare-ups often happen in cycles and are likely to occur in certain seasons. This condition usually becomes more noticeable in the spring and summer at the initial stages, but over time, it can occur all year round. VKC falls under a category of conditions commonly known as “allergic conjunctivitis,” which includes many other types such as perennial and seasonal rhinoconjunctivitis, atopic keratoconjunctivitis, and giant papillary conjunctivitis.
VKC comes in various forms depending on which part of the eye is affected. These include palpebral, limbal, and mixed VKC. Each form of VKC affects a different area of the eye.
Palpebral VKC targets the upper inside part of the eyelid. This condition can result in the inflammation of the eyelid and the front surface of the eye (cornea), potentially leading to serious eye diseases.
Limbal VKC usually affects the white part of the eye around the colored part (the bulbar conjunctiva) near the eyelid and is commonly found in Black and Asian populations.
Mixed VKC, as the name suggests, shows symptoms of both palpebral and limbal VKC.
The first description of swelling around the colored part of the eye (peri-limbal) dates back to 1846 by Arlt. Horner and Tranta later identified white bumps at the limbus (the border between the colored and the white part of the eye), earning them the name Horner-Tranta dots. Gabrielides conducted studies on the fluids secreted by the conjunctiva and found that eosinophils, a type of white blood cell, are a primary component, which further confirms the allergic nature of the condition.
What Causes Vernal Keratoconjunctivitis?
Vernal keratoconjunctivitis is a recurring condition that affects both eyes. It’s more common in boys and usually starts to show up around the age of five. Over time, most cases improve and often go away by the time one reaches puberty. However, in some cases, it can turn into a different condition called atopic keratoconjunctivitis. Vernal keratoconjunctivitis is more prevalent in warm and dry climates, and it tends to get worse in the spring and summer. As time goes on, these seasonal symptoms can become a year-round issue, meaning the longer you have the condition, the more likely your symptoms will persist.
In many cases, patients with this condition have a history of allergies. Interestingly, about half of these patients also have a family history of allergies, suggesting a possible genetic link to the disease. Other factors that make someone more likely to get this condition include being male, being around animals often, and being exposed to a lot of dust and sunlight.
The symptoms of vernal keratoconjunctivitis result from an immune response; both allergic reactions (IgE-mediated) and cell-mediated immune mechanisms are believed to be at play. One specific immune cell, the eosinophil, has been found to be active in patients with this condition. Recent research has found a higher than usual number of eosinophils in the tissue that lines the inside of the eyelids and covers the white part of the eye (conjunctiva) in these patients. Other studies highlight the role of a type of immune cell called CD4 T helper cells in causing symptoms. Additionally, substances that alter the immune response (interleukins 4, 5, 13, and fibroblast growth factors) have been implicated in playing a role in this condition. Moreover, patients with this condition have been found to produce higher levels of immune signaling proteins (cytokines and chemokines) in their conjunctiva.
Risk Factors and Frequency for Vernal Keratoconjunctivitis
Vernal keratoconjunctivitis, a type of eye inflammation, is seen more frequently in certain parts of the world. It tends to be more common in tropical and sub-tropical countries and places with warm, dry climates. Cooler countries, like the United States, have fewer cases, with the rate standing at about 0.29 cases for every 10,000 people. The situation in Europe varies, with anywhere from 1.2 to 12.6 cases per 10,000 people. However, countries like Africa see a lot more cases, with rates ranging from 2% to 37%.
The same geographical pattern is seen with complications from this disease, which can lead to blindness. Europe’s complication rates range from 0.30 to 2.26, Italy’s vary between 0.4 to 4.8, and Norway’s are as low as 0.1 to 1.0.
It’s also worth mentioning that vernal keratoconjunctivitis affects males more than females. Based on a study done in Ethiopia, males were over four times more likely to get the condition than females. A similar report from Rwanda showed males were 1.7 times more likely to be affected. The trend of the disease being more common in males has also been observed in Italy.
Signs and Symptoms of Vernal Keratoconjunctivitis
Vernal keratoconjunctivitis is a severe eye disease that affects mainly young boys, causing significant discomfort. Symptoms of this condition include itching, sensitivity to light (photophobia), burning sensation, a feeling of having a foreign object in the eye, thick excessive eye discharge, and excessive tearing. Parents might notice that children affected by this condition tend to blink a lot and consistently rub their eyes.
The signs that doctors look for during examination depend on the specific type of the disease, and these types can vary based on where you live.
With palpebral disease (a type of vernal keratoconjunctivitis), the initial signs include redness and swelling in the inner surface of the eyelid. As the disease becomes more severe, the eyelid can develop small, flat growths and whitish inflammation. As the disease progresses, larger growths might form and mucus may accumulate between these growths. A mild form of this disease usually has less redness and mucus production.
Bulbar disease, also known as limbal disease, is more common and severe in tropical regions. This form of the disease brings about swelling of the clear outer layer of the white part of the eye. It can also cause a thickening of the area around the cornea (the clear layer in front of your eye), which is associated with white cell collections known as Horner Tranta Spots.
Corneal signs are more common with palpebral disease and can include superficial small corneal erosions or larger erosions. Larger erosions occur due to inflammation and the rubbing effect of these growths. Severe forms can lead to plaques and shield ulcers that can significantly affect vision. These shield ulcers are challenging to heal and can often result in scars or keratinization (hardening), which affects vision. Prompt and aggressive treatment of shield ulcers is necessary to prevent secondary bacterial infection of the cornea.
Pseudogerontoxon is a condition characterized by a ring of superficial scarring near the inflamed cornea, and it often resembles another condition known as arcus senalis. Vernal keratoconjunctivitis can also cause corneal irregularities, particularly keratoconus, resulting from continuous eye rubbing. In some cases, it can even be associated with a viral infection of the eye.
Lid signs such as inflammation of the eyelid (blepharitis) are often associated with vernal keratoconjunctivitis. Some patients might also have eyelid skin changes or damage. In rare scenarios, the disease can lead to scar tissue formation that connects the eyelid to the eyeball (symblepharon) due to the inflammatory complications.
Testing for Vernal Keratoconjunctivitis
Vernal keratoconjunctivitis, or VKC, is typically diagnosed based on a doctor’s findings during a physical examination, in addition to what the patient is experiencing. This condition isn’t usually hard to identify because of its distinctive signs and symptoms.
To determine how severe the condition is, doctors use special stains and scoring systems. These might include the use of fluorescein stain, lissamine green stain, and a technique called confocal microscopy. Some useful scoring systems to measure how severe VKC is are the Oxford scores and Van Bijsterveld scores.
The VKC-Collaborative Longitudinal Evaluation of Keratoconus Study (VKC-CLEK) is another scoring system that has been found useful in checking the severity of VKC. This study looks at the damage to specific parts of the eye known as the limbal and tarsal epithelium.
In addition to these techniques, corneal topography, a test that measures the curvature of the front surface of the eye, can help in diagnosing VKC. A particular type of this test known as videokeratography, which is based on a system named the Placido disc-based system, has been found useful in detecting and preventing severe forms of a related condition known as keratoconus.
On some occasions, further lab tests like conjunctival scrapings might be needed, especially for patients whose symptoms don’t seem to match VKC or if the usual treatment isn’t working. A conjunctival scraping is a test where a small sample of cells is taken from the surface of the eye to be examined under a microscope. The goal of this test is to search for a type of white blood cell called eosinophils that might be present.
Examinations for IgE levels, a type of antibody, as well as skin tests to look for specific allergens, can sometimes be performed. However, these tests don’t often add much to the diagnosis of VKC.
Treatment Options for Vernal Keratoconjunctivitis
Treating vernal keratoconjunctivitis, an eye condition often associated with allergies, comes down to how serious it is when it’s first diagnosed. Doctors might advise taking simple steps to avoid irritation, or in more severe cases, they might suggest surgery.
Simple steps to manage this condition include avoiding anything that you know triggers your allergies. It can also help to put a cool cloth over your eyes, wash your eyelids gently, and wear sunglasses to protect your eyes from glaring light and allergens in the air. If these methods don’t help enough, it may be beneficial to leave hot, windy environments and move to colder areas.
For patients with more serious symptoms, doctors may prescribe eye drops that stabilize mast cells, a type of white blood cell that can trigger allergic reactions. Using these drops with antihistamine eye drops, which block histamine from causing inflammation, can also help.
In really severe cases, prescription eye drops that contain steroids may be helpful. Steroids work by reducing inflammation. Doctors keep a close eye on patients using steroid eye drops, as these can sometimes increase pressure within the eye. If steroid eye drops are needed repeatedly, your doctor may suggest another medication that decreases inflammation, such as cyclosporine or tacrolimus. These medications work by reducing substances that can lead to inflammation.
If you have this kind of eye condition and also have skin or lung conditions related to allergies or asthma, you might need medication for your entire body, not just eye drops. For example, drugs like montelukast, which is used to treat asthma, or dupilumab, which is used to treat atopic dermatitis, a type of eczema, have been found to help with this eye condition. There’s also a medication called omalizumab which has been used off-label to treat severe cases of this condition.
What else can Vernal Keratoconjunctivitis be?
When diagnosing vernal keratoconjunctivitis, other eye conditions similar to it need to be considered. These include different types of allergic conjunctivitis such as:
- Seasonal allergic conjunctivitis
- Perennial allergic conjunctivitis
- Atopic keratoconjunctivitis
- Giant papillary conjunctivitis
Most of these conditions are caused by an overreaction of the immune system. However, giant papillary conjunctivitis is an exception. None of these conditions are more common in one gender, except for atopic keratoconjunctivitis and vernal keratoconjunctivitis, which are more often found in males. A careful examination and the patient’s medical history are very helpful in distinguishing between these conditions.
Vernal keratoconjunctivitis is often confused with atopic keratoconjunctivitis. The key differences between them include the age when people usually get them — people get vernal keratoconjunctivitis when they are in their early teens, while people get atopic keratoconjunctivitis anytime between 20 and 50 years old. Atopic keratoconjunctivitis is often found together with asthma, rhinitis, and dermatitis. Atopic keratoconjunctivitis is also a chronic condition and can lead to scarring of the conjunctiva, while episodes of vernal keratoconjunctivitis usually resolve on their own and do not lead to serious vision problems. Lastly, vernal keratoconjunctivitis is associated with an increase in goblet cells (a type of cell found in the conjunctiva), whereas atopic keratoconjunctivitis is associated with a decrease in these cells.
What to expect with Vernal Keratoconjunctivitis
Vernal keratoconjunctivitis is a condition that usually resolves itself. Most commonly, symptoms disappear around puberty. Typically, this is a non-threatening condition that does not harm your vision. However, in rare instances, complications such as keratoconus (a cone-shaped bulge of the eye), shield ulcers, corneal scarring, and blood vessels growing in the eye can happen, significantly affecting one’s ability to see. Corneal ulcers occur in about 9.7% of patients.
Unmonitored use of corticosteroids (a type of medicine) can create complications such as cataracts (cloudiness in the lens of the eye), or glaucoma (a condition that damages your eye’s optic nerve). These complications can cause permanent vision problems. It’s important to note that in some cases, symptoms may continue into adulthood in about 12% of cases.
Possible Complications When Diagnosed with Vernal Keratoconjunctivitis
People with vernal keratoconjunctivitis, a type of eye inflammation, can experience various complications including:
- Steroid-induced cataract: This is when steroids used for treatment lead to clouding in the lens of the eye, impairing vision.
- Steroid-induced glaucoma: Increased eye pressure due to steroid use, which damages the optic nerve.
- Irregular astigmatism: An uncommon shape of the eye’s cornea or lens, causing blurred or distorted vision.
- Keratoconus: A condition where the cornea, the clear layer at the front of the eye, bulges out and forms a rounded cone shape.
- Acute hydrops: A sudden and painful swelling in the cornea.
- Shield ulcer: A large, grayish erosion appearing on the cornea.
- Central corneal scars: Scarring in the center of the cornea, which can cause blurred vision.
- Limbal tissue hyperplasia: Overgrowth of limbal tissue (the border area between the cornea and the white part of the eye).
Recovery from Vernal Keratoconjunctivitis
Vernal keratoconjunctivitis treatment primarily relies on medications. It’s important to know that this condition can come and go, often causing severe itching that might disrupt daily activities. One essential part of the treatment is letting the people affected by it learn about its natural course.
For acute episodes, or sudden and severe attacks of the disease, steroids are typically used. After that, antihistamine mast cell stabilizers or immunosuppressants, which are medicines that reduce or prevent the body’s normal immune response, are typically used to maintain therapy.
Once treatment with topical steroids (eye drops or ointments) begins, patients need regular check-ups to monitor the pressure inside their eyes (intraocular pressures). In severe cases, where vision is threatened, patients might need rehabilitation therapy involving the use of low vision aids.
Preventing Vernal Keratoconjunctivitis
It’s important for patients to understand their condition, which includes recurring episodes and the fact that it often gets better on its own around puberty. Patients should be aware of common triggers such as dust, sunlight, and pets, and learn how to avoid them. It may be helpful to wear an eye cover whenever there’s a chance of coming into contact with these triggers.
Moreover, patients should use their eye drops exactly as their doctor instructed. This will help manage their condition effectively. They should also be made aware of any potential risks or complications associated with their condition, and understand the importance of regular check-ups to monitor their health progress.
