Hello my friend I am Dr.Arianisa Thanks for your question on HCM Although shiitake mushrooms are beneficial, some people can have an allergic reaction to them. A shiitake mushroom allergy, also called shiitake dermatitis, is not typically life-threatening, but its symptoms can be uncomfortable and even debilitating. This reaction usually develops when the mushrooms are only partly cooked or consumed raw. Allergy symptoms can also be caused by a sensitivity to salicylates, which are chemicals found in every plant. See a doctor if you suspect you are allergic to shiitake mushrooms. Your doctor may perform an allergy test to make sure that shiitake mushrooms are indeed the cause of your symptoms. With your doctor’s approval, take an antihistamine to ease general symptoms and discomfort. Your doctor may also give you an oral or topical steroid to help relieve symptoms, such as itching and a rash. To prevent future allergic reactions, do not touch, eat or inhale shiitake mushrooms or any products that might contain salicylates or lentinan. Hope this information is helpful to you Best regards