Allergic Conjunctivitis

Allergic conjunctivitis is a condition whereby airborne allergens precipitate type 1 IgE-mediated hypersensitivity reactions in the conjunctiva. 

Allergic Conjunctivitis. Conjunctival injection, chemosis, and a follicular response in the inferior palpebral conjunctiva are seen in this patient

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.

Clinical Features: 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. 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. 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.

Vernal Conjunctivitis. The tarsal conjunctiva demonstrates giant papillae and a cobblestone appearance pathognomonic for vernal conjunctivitis

Management:

1. 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.
2. Topical tear substitutes are effective to dilute or wash away the allergen. 
3. H1 antihistamine-vasoconstrictor combinations such as over-the-counter Naphcon A are recommended to relieve mild itching and redness. 
4. For more severe or frequent attacks, olopatadine, an antihistamine with mast cell stabilizing properties, is more effective. 
5. Mild topical steroids are an option only after consultation with an ophthalmologist.
6. Options for vernal conjunctivitis include cromolyn, aspirin, and cold compresses. 
7. Topical cyclosporin may be useful in resistant cases.

Important Points To Remember: 

1. Itching is the hallmark symptom of allergic conjunctivitis.

2. Itching is not common in nonallergic conjunctivitis.

3. Symptoms are usually bilateral.

4. Naphcon A and olopatadine are effective in treating allergic conjunctivitis.

5. Complications of topical corticosteroid use include glaucoma, cataract formation, secondary infection, and corneal perforation.