[Characteristics of the development of experimental allergic contact dermatitis].

Histological and electron microscopic examination of changes in the skin and blood revealed three different stages in the development of experimental allergic contact dermatitis (ACD). The primary contact reaction (24 hours) had features of nonspecific inflammation with some morphological signs of initial sensitization. Inflammation in the flare-up reaction (5-7 days) is the result of the immune process, and basophilic infiltration of the skin is the obligatory component of this reaction. ACD (patch test at 15 days) was shown to have morphological manifestations typical of the delayed type hypersensitivity and some signs of the immediate type reactions.