Corticosteroids are widely used for the management of many diseases because of anti-inflammatory and immunomodulatory properties. Sulfite intolerance is well known but immediate hypersensitivity to corticosteroids is rarer and must be reported.We report a case of a 38-year-old man, followed since 1986 for asthma with sulfite intolerance. He twice developed urticaria after ingesting betalactam antibiotics associated with corticosteroids of the group A, according to the Matura and Goossens's classification. The allergy inquiry confirmed not only a beta-lactame allergy but also in corticosteroids of the group A. Intradermal reactions with methylprednisolone and hydrocortisone were positive at 7 mm for methylprednisolone on 1/1000 dilution and at 4 mm for hydrocortisone on 1/10 dilution. Thus immediate allergy to corticosteroids was confirmed. But those skin tests were negative for corticosteroids of group B and C. In order to propose an alternative therapy for acute asthma, an intravenous injection of 4 mg of betamethasone was performed without inducing immediate and delayed allergic reactions.Corticosteroid allergy is rare and can be fatal. Many asthmatic or acetylsalicylic acid intolerant patients may be concerned. The diagnostic of corticosteroid allergy have to be confirmed by clinical history and skin tests of the different groups to try to identify one or more allergens and to propose a alternative treatment if necessary.