The following morphologic changes is most consistent with allergic, rather than irritant, contact dermatitis: (A) Lymphocytic exocytosis, (B) Papillary dermal edema, (C) Eosinophilic infiltration, (D) Spongiosis
Answer is C. Allergic form results from prior sensitization to specific allergens and  is accompanied by prominent eosinophilia, Spongiosis is common to  both allergic and non-allergic contact dermatitis.