A 65-year-old retired male (Fitzpatrick phototype II) previously healthy except for a distant history of basal cell carcinoma presented to our dermatology clinic with a two-day duration of a rash. The lesions were first noticed on his chest, upper extremity and back []. The rash was extremely pruritic resulting in insomnia for the previous 2 nights which went unrelieved despite oral diphenhydramine. Also concerning to him and his wife was the whip like nature of the rash which was somewhat linear and run vertically right down his back in a manner unlikely to be produced by simple excoriation. In addition, he denied reaching for or scratching his back in any manner. Review of systems was negative, and he denied any recent history of travel, similarly sick contacts or recent outdoor contactants or change in body soaps or laundry detergents.\nHe denied any prior history of similar rashes and his past medical history was non-contributory. A detailed exposure history revealed the patient had eaten mushrooms 48 hours ago during dinner at a Chinese cuisine buffet. He admitted to ingesting great quantities of a medley of cooked and raw mushroom including the Shiitake mushroom variety.\nPhysical examination was striking with a truncal dominant but generalized rash in a centripetal distribution (). The lesions consisted of raised, relatively uniform erythematous papulovesicles arranged in linear arrangement. Close-up views [] confirmed the papulo-vesicular nature of the rash with multiple small papules grouped both along the breadth and length of each linear streak within an erythematous background.\nGiven the clinical history and presentation the diagnosis was consistent with a shiitake dermatitis. Flagellate patterns of eruption have also been noted in drug reactions particularly to bleomycin, peplomycin (a bleomycin derivative), docetaxel, adult-onset Still’s disease, and dermatomyositis [].\nThe patient was put on a mid-potency topical steroid (Triamcinolone 0.1% ointment applied to affected areas twice daily). The rash resolved within 1 week. It has been reported that shiitake dermatitis can also resolve spontaneously.
Male patient, 30 years old, white, born and living in Rio de Janeiro, RJ, Brazil,\ncomplained of intense pruritus followed by disseminated erythematous lesions with onset\nless than 24 hours before. He had no history of associated diseases, use of any\nmedications or any other associated factors. On the first inspection we noted small\nerythematous papules and some petechiae that assumed a linear pattern located on the\ntrunk, lower and upper limbs. There were no mucosal abnormalities, fever or any other\nsystemic symptoms ( and ). Based on the peculiar rash, the patient was\nquestioned about the ingestion of shiitake and confirmed he had eaten a\nlarge amount of raw mushrooms five hours before the cutaneous lesions appeared, leading\nus to the diagnosis of flagellate erythema due to shiitake\ningestion.