Place of immunological examinations in extrinsic asthma.

The provocation test is - in spite of its drawbacks, especially the risk for the patient - the most reliable way to identify causative agents in extrinsic asthma. The immunological genesis of the obstruction provoked must be proved with adequate methods however. RAST (Radio-allergo-sorbent-test) and histamine liberation are valuable in vitro techniques for the identification of atopic sensitizations. Their disadvantages - the expensive equipment and the time-consuming procedure respectively - limit their widespread use. A carefully performed and evaluated prick test possesses a comparable specificity with acceptable risk. Less satisfying is the situation in nonimmediate asthma. Precipitations tests are at present most valuable. Main indications for immunological methods in extrinsic asthma are: - the identification of causative allergens and the kind of underlying immune reactions; - the control and - in the future - the individualization of hyposensitization procedure. The future use of allergen extracts containing a minimum of non-specific irritants is extremely important.