The PATHOGNOMONIC slit-lamp finding in vernal keratoconjunctivitis (VKC) that distinguishes it from all other forms of allergic conjunctivitis is:

• A Chemosis with papillary hypertrophy on the lower tarsal conjunctiva
• B Follicular reaction in the inferior fornix
• C Phlyctenular nodule at the limbus
• D Giant cobblestone papillae (>1 mm) on the superior tarsal conjunctiva ✓

Explanation

Giant cobblestone (macropapillae > 1 mm) on the upper tarsal conjunctiva are pathognomonic of vernal keratoconjunctivitis. They represent foci of collagen deposition with mast cells, eosinophils, and fibroblasts. In the limbal form, gelatinous limbal infiltrates with Trantas' dots (clusters of eosinophils and degenerate epithelial cells) are seen. Lower tarsal papillary hypertrophy occurs in atopic keratoconjunctivitis and giant papillary conjunctivitis. Inferior fornix follicles indicate viral or toxic reactions.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.