<prompt> Phlyctenular conjunctivitis is:Type I reactionType II reactionType III reactionType IV reaction  <response>: Ans.: D Type IV reaction Phlyctenular Keratoconjunctivitis Etiology Khurana 5th75It is believed to be a delayed hypersensitivity Type IV-cell mediated response to endogenous microbial proteins.Causative allergens1. Tuberculous proteins were considered, previously, as the most common cause.2. Staphylococcus proteins are now thought to account for most of the cases.3. Other allergens may be proteins of Moraxella Axenfeld bacillus and certain parasites worm infestation. 