A nut allergy consists of a hypersensitivity to tree nuts. For the millions of people who suffer from nut allergy, eating nuts can cause an overreaction of the immune system, which may lead to severe physical symptoms. Nut allergies occur mainly in children, and are treated with a restricted diet avoiding foods that may be contaminated with tree nuts, nut particles, or nut oils. Unfortunately nut allergy is especially dangerous because nuts are hidden in so many places where you might not expect to find them – they even show up in lotions and shampoo. Reactions range from mild, like hives on the skin, to more severe and involving multiple parts of the body. The most severe reaction is called anaphylaxis and is an emergency situation that requires immediate attention and treatment with epinephrine.