<prompt> Spring catarrah is -Type I hypersensitivity reactionType II hypersensitivity reactionType III hypersensitivity reactionType IV hypersensitivity reaction  <response>: It is considered a hypersensitivity reaction to some exogenous allergen, such as grass pollens. VKC is thought to be an atopic allergic disorder in many cases, in which IgE-mediated mechanisms play an impoant role. Such patients may give personal or family history of other atopic diseases such as hay fever, asthma, or eczema and their peripheral blood shows eosinophilia and inceased serum IgE levels. Ref: A K KHURANA COMPREHENSIVE OPHTALMOLOGY,E4,page-74 