Pityriasis lichenoides-like drug reaction with numerous eosinophils

Abstract

Pityriasis lichenoides-like drug reactions simulate pityriasis lichenoides clinically and histopathologically, though important differences exist. As a rule, pityriasis lichenoides has minimal to no eosinophils. However, this case illustrates that pityriasis lichenoides-like drug reaction can present with numerous eosinophils. This, in our experience is not rare, but contrasts with clinical reports in the literature that describe pityriasis lichenoides-like drug reactions with minimal to no eosinophils in the infiltrate. While similar, distinguishing these diseases is important given that pityriasis lichenoides is a lymphoproliferative disorder with a more protracted clinical course that is difficult to treat. We provide histopathological clues to aid in this important distinction.

Keywords: PItyriasis lichenoides; drug hypersensitivity; eosinophils; inflammatory infiltrate; pityriasis lichenoides-like drug reaction.