classic reaction to raw or undercooked shiitake mushrooms

 The little blisters he noted on her hands initially had hardened, and the red streaks were much darker, almost purple, and raised. The way those welts now streaked across her neck, back, legs and abdomen made it look as if she had been flogged.

“We think this is a classic reaction to raw or undercooked shiitake mushrooms,” Larsen told her. Shiitake dermatitis, as it’s known in medical jargon, was first described in 1977. Since then, it has been frequently reported in Asia, though rarely, if ever, in the U.S. The rash is thought to be a toxic reaction to a starchlike component of the shiitake mushroom. This component, known as lentinan, breaks down with heat, and so this reaction is seen only when the mushrooms are eaten raw or partly cooked.

http://www.nytimes.com/2011/02/20/magazine/20fob-diagnosis-t.html?_r=1&ref=health