Shiitake Mushrooms are commonly eaten in Asia. With the easternization of the west in recent years, these have become common place in restaurants in Europe and America too.

Though considered a delicacy, undercooked Shiitake mushrooms are poison and should be avoided as the cause a dramatic itchy skin rash referred to as Shiitake Dermatitis. The toxic chemicals within the mushroom not only cause a toxic reaction but can also induce an allergic reaction. Once you have had this reaction, one should not consume Shiitake again in future.

The photos below from a recent consultation show the dramatic nature of the rash which appears typically as streaks on the trunk, as if the person has been ‘whipped’.

As you can see, the rash can present in various forms including small blisters on the hand, skin hives, red spots on skin etc. The rash usually appears 2 days after ingesting the mushrooms and can last for 2-3 weeks (or longer if left untreated).

This is one of the ‘Once seen, never forgotten’ conditions in Dermatology!