[Desensitization of allergy to hymenoptera venoms]

Hyposensitization (immunotherapy) of hymenoptera venom allergy has been practised for 70 years. About 20 years ago the use of ineffective whole-body extracts was abandoned, as effective therapy with preparations of bee venom and wasp venom became available. The diagnosis of hymenoptera venom allergy is based on history, skin tests and determination of venom specific IgE-antibodies in the serum. Only rarely other tests are needed (histamine or leukotriene release tests, immunoblot, specific IgG antibodies). To achieve a definite diagnosis, all findings have to be considered carefully, as "false positive" and "false negative" results can occur in all test systems. Hyposensitization is indicated in all patients with systemic IgE-mediated immediate type reactions, only in children with exclusive skin symptoms it may not be needed. Contraindications of hyposensitization are to be considered. Allergen preparations for subcutaneous injection are available as aqueous preparations or as aluminium hydroxide-adsorbed depot extracts. Various rush or conventional treatment protocols are used to reach the maintenance dose of usually 100 micrograms venom/four weeks. The most frequent side effects are large local reactions, which are observed in almost all patients. Systemic anaphylactic side effects also occur in up to 40%, in most cases the symptoms are mild. To identify patients who are not protected by the usual maintenance dose, a sting challenge test with a living insect should be performed. By this, about 80 to 100% of the patients are found to be protected from systemic symptoms, and in those still reacting an increased dose of 200 micrograms (or even higher) eventually induces protection. Hyposensitization may be stopped if it lasted at least for 3 to 5 years, if systemic side-effects did not occur and if the patient has tolerated a sting challenge or a field-sting without systemic symptoms. In patients intensely exposed to hymenoptera or in those with an increased risk of severe reactions, longer treatment has to be considered.