Clindamycin-Induced Dermatitis and the Sparing Phenomenon: A Case Report.

Drug-induced dermatitis is a type IV, T-cell-mediated, hypersensitivity reaction characterized by the development of a rash in response to drug exposure. The sparing phenomenon, where drug-induced rash spares areas of recent skin disease, is a recognized but relatively rare clinical observation. In this report, a 62-year-old woman presented to the emergency department with drug-induced dermatitis secondary to clindamycin that spared a recent site of Pasteurella multocida cellulitis. This case visually highlights the complex interplay between T-cell activation and the local immune environment.