WHAT IS VERNAL CONJUNCTIVITIS?Vernal conjunctivitis, or vernal keratoconjuctivitis (VKC) is an eye inflammation from the spectrum of allergic eye conditions termed atopic eye diseases. In this case the allergy in combination with certain climate causes an overwhelming inflammatory reaction in the conjunctiva and cornea. Pediatric ophthalmologists and allergists are specialists who usually treat Vernal conjunctivitis. While the primary care provider and nurse practitioner may see patients with allergic conjunctivitis as outpatients, they should always be alert for patients with visual changes or severe symptoms. Empirical prescription of topical steroids by the primary care providers is not recommended as these agents can also cause cataracts; referral to an ophthalmologist is prudent.
DEMOGRAPHICSMore commonly seen in males (ratio 2:1 to 3:1) in dry, warm climates. Most cases occur in patients younger than ten who often have a history of atopy or asthma. Many patients have complete resolution without the return of symptoms after adolescence. More than 60% of patients had repeated recurrences all year round.
SYMPTOMS OF VERNAL CONJUNCTIVITISSymptoms of vernal conjunctivitis do not differ from other atopic eye diseases:
- Goopy eyes (thick mucoid discharge)
- Red eyes
- Feeling of ‘sand’ in the eyes
- Congested or runny nose
- Postnasal drip
- Asthma and cough
- Allergic blepharitis
- Reactions to cats or dogs
PATHOPHYSIOLOGYIt is not well understood why exactly a specific reaction that happens in certain patients to the same allergens brings different reaction of the immune system. Simple allergic conjunctivitis (acute, seasonal and perennial) is an immunoglobulin E (IgE) mediated hypersensitivity reaction (type I) and resultant mast cell degranulation secondary to direct contact with an allergen to the ocular surface. As such, there is an immediate and delayed phase of the reaction mediated by different inflammatory modulators. The exact mechanism involved in vernal keratoconjunctivitis is not well understood, but it is likely that there is an IgE mediated hypersensitivity as well as T cell involvement in the reaction. Vernal Keratoconjunctivitis will show an accumulation of eosinophils, mast cells, and proliferation of fibroblasts. Biochemical stains will reveal the presence of proteases, chymase, and tryptase. The substantia propria is thickened due to collagen deposition. Both T and B lymphocytes are present which release IgE and IgG. The overall picture resembles both type 1 and type IV hypersensitivity reaction.
WHAT CAUSES VERNAL CONJUNCTIVITIS?An allergic sensitization to the environmental protein starts the atopic cascade in the body. While sensitization can happen during the previous year grass season, the symptoms may not start until the next year (latent period). Switch of the immune system responses from neutral to aggressive (TH2 immune phenotype) starts the attack of the cells and histamine release when the allergen comes in direct contact with mucous membranes in the eyes and nose. Then the tissue swells up and gets inflamed, bbecause the immune cells damage surrounding tissues while trying to “kill” the protein of the pollen of cat hair.
DIAGNOSING VERNAL CONJUNCTIVITISThe diagnosis is made clinically with a thorough history and classic physical examination findings. If there is any concern based on the history and physical examination, fluorescein staining of the cornea can be used to ensure that there is no corneal abrasion. Laboratory testing is generally not needed, although skin prick or serum allergy testing can be helpful for mitigating the disease process by identifying the offending allergens so that they can be avoided if possible. As all diseases caused by allergy, a skin prick test for the environmental allergen extracts should be performed. Recommended allergens include:
- Indoor environment (dust mites, cockroaches, mice, cat, dog, feather)
- Outdoor environment (trees, grasses, weeds)
- Molds (indoor and outdoor)
- Allergic rhinitis
- Oral allergy syndrome
TREATMENT OPTIONSGeneral allergic eye care is an important way to reduce or prevent symptoms:
- avoid rubbing eyes
- use artificial tears and cool compresses
- avoid allergen exposure
- wash the face with cold water, wash the eyelids and forehead from the nose – out
- eye antihistamine drops: olopatadine, azelastine
- cold compresses
- oral antihistamines of the IV generation (non-sedating): cetirizine, levo-cetirizine, fexofenadine
- antihistamines that cause drowsiness (can be used at night): Benadryl, Hydroxyzine
- Sodium chromolin
PROGNOSISIn most patients, the prognosis is good. Complications are rare but recurrence of symptoms is not uncommon. For patients who sustain corneal damage, this may be associated with visual loss. The medications used to manage allergic conjunctivitis may sometimes also induce cataracts.
POTENTIAL COMPLICATIONSAn Italian group of scientists lead by Massimo G.Bucci,MD from the Department of Ophthalmology, University of Rome “Tor Vergata” and the G. B. Bietti Eye Foundation, Rome, Italy reports: A marked conjunctival sensitivity to nonspecific stimuli was noted in more than one third of patients. In 6% of cases, a reduction of visual acuity resulted from corneal scarring, and in 2% of patients, steroid-induced glaucoma was observed. The large size of giant papillae indicates poor prognosis for the persistence of the disease and its evolution into a chronic, perennial condition.