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.
The patient was a previously healthy 23-year-old Caucasian male who complained of the sudden onset of linear rash on his trunk evolving for 2 days. The patient denied other symptoms, such as pruritus, arthralgia, mucosal abnormalities, and fever. When asked about consumption of shiitake, he confirmed that he had eaten those mushrooms 4 days before he sought medical assistance and stated that he thought the shiitakes had been well cooked. The patient denied the intake of other medications or changes of personal hygiene products.\nAt physical examination, the patient presented with small, grouped papules forming a linear design, spreading on the trunk and extending to the proximal part of the upper limbs (Fig. , , ). No alterations on the face, scalp, or mucosa were observed. Dexamethasone ointment was applied for 5 days in the area of the lesions, and complete remission was observed after 7 days.