[Hyposensitization in bronchial asthma--still a current therapeutic procedure?]

39 patients with proven extrinsic asthma underwent a placebo-controlled crossover, single-blind hyposensitization study for two years. 29 persons completed the study. Neither one year of hyposensitization treatment nor one year of placebo led to an appreciable change in the allergen dosages eliciting significant asthmatic reactions in bronchial challenge tests. Allergen-specific bronchial hyperreactivity was lost twice after allergen treatment and four times under placebo. Only when one assumes a more favorable outcome in patients with immediate asthmatic reactions as compared with those with dual or late asthmatic reactions could hyposensitization be shown to be superior to placebo: during hyposensitization 50% of patients with dual reactions changed to immediate reactions (in the case of placebo 7%); placebo was associated rather with a change from immediate to dual reactions in 31% (in the case of hyposensitization 0%). No parameter could be found by which individual outcomes of hyposensitization could be predicted. It is concluded that hyposensitization should be performed only if avoidance of causative allergens is not possible and drug treatment, including inhalant corticosteroids and cromoglycate, has not proved to be efficient.