It occurs as a result of hypersensitivity reaction due exposure to allergic substances.

Clinical features:

Ø  The patient present with marked itching and watery discharge.

Ø  History of allergy is usually present.

Ø  On examination, conjunctival papillae and edema over eyelids is seen.

Non- pharmacological treatment:

l  Cool compresses several times per day and avoid offending agents.

Pharmacological treatment:

1.       Topical anti-inflammatory and anti-histaminic drops, depending on the severity (olopatadine 0.1% OD/BD, nedocromil 2% TDS, or ketotifen 0.025% BD, ketorolac 0.5% QID).

2.       In severe cases, mild topical steroid (e.g., loteprednol 0.2% or fluorometholone 0.1%, QID for 1 to 2 weeks) may have to be added. Steroids are gradually tapered as patient responds to medications.

3.       Preservative free artificial tears four to eight times per day.

4.       Investigate for offending agents and avoidance of the same.

5.       Oral antihistamine (e.g., diphenhydramine 25 mg TDS/QID or cetrizine/levocetrizine/montelukast /loratadine 10 mg OD) can be helpful in severe cases and in cases with associated systemic allergy.