[Diagnosis of penicillin allergy. Results of a clinical investigation program]

Investigations concerning penicillin allergy (PA) from abroad suggest that considerable overdiagnosing occurs. The absence of standardized commercially available preparations for skin testing and the time necessary for thorough testing are also contributory causes. Fifty patients with suspected PA were investigated with a programme consisting, in serial order, of RAST for IgE to penicillin V and G, a cutaneous test with a commercially available test preparation (Penkit), first with a prick followed by intracutaneous testing and finally with oral provocation. If a positive reaction occurred, the test was discontinued. Six patients (12%) had positive RAST or cutaneous reactions, (1 positive to RAST, 2 to prick and three not until the intracutaneous test), while no patients with negative RAST and cutaneous tests reacted to oral provocation. No generalized allergic reactions occurred during testing. It did not prove possible to predict which patients would react positively on the basis of the case histories. This investigation thus demonstrates that PA is also considerably overdiagnosed in Denmark and that a programme of investigation such as this is suitable for testing for PA and, finally, that the programme of investigation can scarcely be simplified.