Recognizing Flagellate Erythema in Skin of Color: A Case of Shiitake Dermatitis

Flagellate erythema, also known as flagellate dermatitis, flagellate hyperpigmentation, or shiitake dermatitis, is a rare multifocal cutaneous eruption characterized by linear erythematous lesions similar to flagellation wounds. This case report details the progressive onset of flagellate erythema in a 31-year-old African American male presenting with pruritic, erythematous, hyperpigmented, linear lesions of the face, trunk, and upper extremities following his consumption of shiitake mushrooms. Classically, this eruption arises subsequent to the ingestion of raw or undercooked shiitake mushrooms. This case underscores the importance of clinical diagnosis, as the role of biopsy as a diagnostic tool is limited due to the nonspecific nature of histological findings. Therefore, proper diagnosis is reliant upon careful history taking, including dietary changes, initiation of any new medications, and progression of symptoms. Most cases are self-limiting, with eruptions persisting for up to three weeks. Treatment aims to provide symptomatic relief through topical corticosteroids and oral antihistamines, reducing associated pruritus and skin changes.