Phlycten is due to -: (A) Exogenous allergy, (B) Endogeneous allergy, (C) Viral keratitis, (D) Fungal keratitis
Answer is B. Phlyctenular conjunctivitis - Endogenous allergy It is believed to be a delayed hypersensitivity (Type IV cell mediated) response to endogenous microbial proteins. Causative allergens are :- (i) Staphylococcus proteins (most common); (ii) Tuberculous proteins and (iii) Proteins of Moraxells axenfeld bacillus and ceain parasistes. Vernal keratoconjunctivitis - Exogneous allergy Reference : AK khurana 7th edition