002 Shiitake dermatitis: Not mush-room for shrooms

In rare occasions, ingestion of raw or undercooked shiitake mushrooms (Lentinus edodes) can result in a unique dermatologic manifestation known as flagellate dermatitis (SFD). The diagnosis SFD is often overlooked due to the rarity condition and commonality mushroom consumption. As consumption increases globally, rise cases may follow suit. Therefore, awareness presentation clinical background critical. Here, we present case middle-aged female. A female presented with an abrupt onset pruritic skin lesions. She denied any other symptoms previous episodes similar rash. Past medical history was noncontributory. However, patient recalled eating just prior outbreak. Physical examination significant for erythematous linear papules that formed flagellate/whip-like patterns across her body. lesions extended from neck abdomen bilateral thighs. 2x3mm biopsy showed superficial perivascular, lymphocytic infiltrate few eosinophils. Fungal staining appropriate controls were positive spores follicular ostia. Her conformed SFD. While mechanism still unclear, theories suggest it stems hypersensitivity reaction lentinan. Lentinan polysaccharide found cell wall mushrooms. heat-labile nature lentinan explain why originate following shiitake. Biopsies commonly demonstrates dermal edema, perivascular infiltrates eosinophils neutrophils. Our further fungal be beneficial when insufficient diagnosing self-resolves, however, oral histamines topical steroids have shown alleviate symptoms. also demonstrated triggered exacerbated by sun exposure suggesting possible photosensitivity component condition.