Eosinophilic panniculitis does not a specific disease entity but reptesents a unique reactive pattern that may be associated with inflarnmatory and immunoreactive dis.ases. Its clinical and laboratory data indicate that there is a group of psychiatric and immunoreactivc allergic patients who develop inflammation of the fat, principally eosinophils, and that this reaction is self-lirnited and nonspeeific in most cases, and probably steroid-responsive. We report a case of eosinophilic panniculitis in a 35-year-old man ieho had developed pruritic tender erythematous plaques on hi. legs and right arm with blood eosinooplilia. Microscopic examinat,ion revealed diffuse eosinophilic infiltration in the subcutaneous fat tissue. (Kor J Dermatol 1993; 31(3): 387-391)