This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Spring catarrh is which type of hypersensitivity reaction - 
Select and explain. 
A. type I, B. type II, C. type II & III, D. All
A: type I
Answer: A: type I 
Explanation: Ans. is 'a' i.e., Type I . Vernal keratoconjuctivitis is a recurrent, bilateral, external ocular inflammation primarily affecting boys and young adults living in warm, dry climates. . It is an allergic disorder in which IgE (type I) and cell mediated immune mechanisms (type IV) play an impoant role.