This review highlights some of the research advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insect venom that were reported primarily in the Journal of Allergy and Clinical Immunology from 2002 through 2003. Among the topics highlighted are new insights into the pathogenesis of atopic dermatitis and potential strategies for more effective treatment of the atopic march. Patients should remain supine with raised legs during anaphylactic shock because upper body elevation could result in sudden death from loss of venous return to the heart. A major advance in food allergy was that humanized, monoclonal anti-IgE antibody showed protection against peanut-induced anaphylaxis. In addition to studies elucidating mechanisms of drug hypersensitivity, a clinical study showed patients with a history of prior penicillin allergy with negative penicillin allergy test results are unlikely to experience reactions or resensitization on subsequent oral courses of penicillin. Lastly, there are new recommendations for patients with convincing insect sting reaction histories but negative skin test responses to venom.