Allergic Conjunctivitis in Adults

Allergic conjunctivitis in adults is immunoglobulin E mediated inflammation of the conjunctiva after exposure to allergens such as pollen, dust mites, animal dander and moulds. It may be seasonal or perennial.

• Mast cell degranulation releases histamine, which causes itching, redness and swelling.
• Vernal and atopic keratoconjunctivitis are severe chronic forms that can threaten vision.
• It often occurs with allergic rhinitis, asthma and eczema.

Bilateral itching, watery or ropy discharge, redness, eyelid swelling, chemosis, burning and a gritty feeling, worse during the allergen season.

• Itching is the hallmark; rubbing worsens symptoms.
• Examination shows pale pink conjunctiva with fine papillae; giant papillae and Trantas dots suggest vernal disease.
• Differential diagnosis: viral conjunctivitis, bacterial conjunctivitis, dry eye, contact dermatitis, blepharitis, giant papillary conjunctivitis from contact lenses, vernal keratoconjunctivitis, atopic keratoconjunctivitis, toxic reaction to drops.
• Complications: shield ulcer and corneal scarring in vernal disease, keratoconus from eye rubbing, cataract and glaucoma from steroids, secondary infection.

Clinical diagnosis.

• History of itching, allergen exposure and atopy; slit lamp examination with eversion of the upper lid.
• Conjunctival scraping for eosinophils in doubtful cases; skin prick or specific IgE testing.
• Fluorescein staining for corneal involvement.

Avoid triggers and use dual action antihistamine drops.

• Supportive: cold compresses, avoid rubbing, allergen avoidance (keep windows closed in pollen season, wash bedding at 60 degrees Celsius, damp dusting), sunglasses, preservative free tears to wash out allergens, stop contact lens wear during flares.
• Pharmacological: olopatadine 0.1 percent or ketotifen 0.025 percent drops twice daily for the season; sodium cromoglicate 2 percent drops four times daily (needs 1 to 2 weeks to work and is used prophylactically); oral cetirizine 10 mg or loratadine 10 mg daily if nasal symptoms; short courses of loteprednol 0.5 percent or fluorometholone 0.1 percent drops four times daily for 1 to 2 weeks for severe disease only under ophthalmology care; ciclosporin 0.05 to 0.1 percent drops twice daily for vernal and atopic disease; tacrolimus 0.03 percent ointment to lids for refractory disease.
• Procedures: supratarsal steroid injection or papillae excision in vernal disease with ulcer, by an ophthalmologist; allergen immunotherapy for refractory seasonal disease.
• Special groups: pregnancy, cold compresses, cromoglicate and preservative free tears, avoid oral decongestants; children, vernal disease needs specialist care and steroid monitoring; contact lens wearers, change lens type or stop.
• Red flags: pain, photophobia, reduced vision, corneal opacity, shield ulcer, prolonged steroid use, intraocular pressure rise.
• Follow-up: review in 1 to 2 weeks after starting steroids; review all severe cases every 3 months.