Skin window: An aid in the diagnosis of drug allergy

Abstract

The skin-window technique was utilized as a means of diagnosis in 22 instances of suspected drug hypersensitivity in 19 patients. Positive reactions, as noted by eosinophil counts of 18 to 97 per cent, were recorded at test sites in all 5 cases of definite drug hypersensitivity in which reactions had occurred within 8 weeks of testing. Positive reactions, as noted by eosinophil counts of 8 to 90 per cent, were recorded at test sites in 10 to 12 cases with probable drug hypersensitivity in which some of the drug reactions had occurred as long as 20 years previously. There were no systemic reactions following the test and only mild local reactions in 2 cases. Negative tests, as noted by eosinophil counts of 0 to 4 per cent, were noted in distilled water controls and in 4 of 5 cases with equivocal drug hypersensitivity. Tests with other drugs being taken by the patients, to which reactions apparently had not occurred, and tests with drugs in nonallergic individuals also gave responses similar to the distilled water controls.