Eosinophilic pustular folliculitis.

Sterile, pruritic papules and papulopustules that formed annular rings developed on the back of a 58-year-old woman. The individual lesions evidenced peripheral extension with central clearing and were characterized by exacerbations and partial remissions. The general health of the patient was good. Laboratory determinations showed moderate peripheral blood eosinophilia. Spongiosis with eosinophilic exocytosis, often localized to the hair follicles, was found on examination of histologic specimens. These findings led to a diagnosis of eosinophilic pustular folliculitis, a disease of unknown cause that has rarely been reported in the North American literature.