Allergic conjunctivitis is a condition whereby airborne allergens precipitate type 1 IgE-mediated hypersensitivity reactions in the conjunctiva. Allergens include pollens, animal dander, mites, mold, and dust. Approximately 50% of patients have a personal or family history of allergic conditions such as atopy, eczema, asthma, and allergic rhinitis.
Itching is the hallmark symptom. Associated clinical features include conjunctival injection and edema, burning, discharge (clear, white, or mucopurulent), chemosis, and eyelid redness and swelling. Small papillae may be seen on the tarsal conjunctiva.
Vernal conjunctivitis is a rare but serious form of allergic conjunctivitis as it may lead to corneal scarring and subsequent vision loss if not treated. The highest incidence is seen in the arid areas of the Middle East and North Africa secondary to wind and dust storms. Symptoms are similar to allergic conjunctivitis, but are more intense. Presentation is typically during childhood. Itching is severe and a vigorous knuckle rubbing is a typical observation. Giant, raised, pleomorphic papillae (“cobblestones”) seen over the upper tarsal plate are pathognomonic.
Allergic Conjunctivitis. Conjunctival injection, chemosis, and a follicular response in the inferior palpebral conjunctiva are seen in this patient with allergic conjunctivitis secondary to cat fur. (Photo contributor: Timothy D. McGuirk, DO.)
Management and Disposition
The initial approach is to eliminate the allergen. Avoiding animal dander, using air conditioners with appropriate filters, and limiting time outdoors will improve the condition. Topical tear substitutes are effective to dilute or wash away the allergen. H1 antihistamine–vasoconstrictor combinations such as over-the-counter pheniramine/naphazoline ophthalmic are recommended to relieve mild itching and redness. For more severe or frequent attacks, olopatadine, an antihistamine with mast cell–stabilizing properties, is more effective. Contact lens wearers should avoid use during allergic conjunctivitis flares. Mild topical steroids are an option only after consultation with an ophthalmologist.
Options for vernal conjunctivitis include olopatadine, mast cell stabilizers such as cromolyn, antihistamines, and cold compresses. Topical cyclosporine and allergen immunotherapy may be useful in resistant cases.
Itching is the hallmark symptom of allergic conjunctivitis.
Itching is not common in nonallergic conjunctivitis.
Symptoms are usually bilateral.
Pheniramine/naphazoline ophthalmic and olopatadine are effective in treating allergic conjunctivitis.
Topical steroids may be considered for refractory symptoms and prescribed under the supervision of an ophthalmologist since complications of use include glaucoma, cataract formation, secondary infection, and corneal perforation.
Vernal Conjunctivitis. The tarsal conjunctiva demonstrates giant papillae and a cobblestone appearance pathognomonic for vernal conjunctivitis. (Photo contributor: William Beck, CRA.)