RESUMO
The oral allergy syndrome is one of the most common form of food allergy and manifests as contact urticaria of the oral mucosa after consumption of cross reacting foods. Whereas allergic contact stomatitis often occurs due to dental materials, allergic contact cheilitis is usually a reaction due to topical therapeutics like herpes ointments or lip care products. As late type reactions are more frequent than immediate type reactions in the anogenital mucosa, contact dermatitis in this area should be identified via epicutaneous testing. In case of contact urticaria at the genital mucosa, a semen allergy or a latex allergy should be given due consideration as a possible cause. Angioedemas, which are mostly common histamine mediated, usually prefer skin areas with loose connective tissue such as the oral or genital mucosa. Fixed drug eruption also occurs preferentially in these areas. Bullous drug-induced skin reactions (e.g., SJS and TEN) are characterized by severe hemorrhagic, erosive affections of mucous membranes.