Shiitake dermatitis.

Shiitake Dermatitis is a skin eruption that resembles whiplash marks and occurs after consumption of raw shiitake mushrooms. It is caused by a toxic reaction to lentinan, a thermolabil polysaccharide which decomposes upon heating. We report the second case of this dermatitis in Brazil. A 25-year-old man presented with linearly arranged erythematous, pruritic papules on the trunk and limbs, after ingestion of a salad containing raw shiitake mushrooms. The eruption was self-limited, resolving within 10 days of onset. The recognition of this entity gains importance due to the increased consumption of shiitake mushrooms in occidental countries.