Abstract

Shiitake mushroom dermatitis, more commonly seen in Eastern Asia, is a rare clinical entity in western parts of the world. However, due to changes in food practices, it may become increasingly more common. Shiitake mushroom dermatitis is thought to arise due to an unknown mechanism involving lentinan, a thermolabile polysaccharide present in uncooked or partially cooked shiitake mushrooms. Here we describe a case of a 54-year-old male who presented to the dermatology clinic with a chief complaint of an acute pruritic rash, which began 5 days prior. Upon obtaining further history, the patient recalled an uncharacteristic consumption of ramen noodles with a large serving of shiitake mushrooms just 24 hours prior to the onset of the rash. Histologically, the rash displayed a spongiotic and superficial perivascular dermatitis with eosinophils. The histological findings of shiitake mushroom dermatitis are nonspecific and thus, it is important for both clinicians and pathologists to be aware of the diagnosis and suspicious when a clinical description indicates a linear or flagellate appearing dermatitis.