<prompt> Phlyctenular conjunctivitis is caused by -ChlaymydiaStaphylococcusPneumococcusAspergillus  <response>: 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. Reference : AK Khurana 7th edition page 85 