The value of routine penicillin allergy skin testing in an outpatient population.

The aim of this study of patients with a history of allergy to penicillin, conducted in two separate surveys approximately 10 years apart, was to determine if (a) elective penicillin allergy testing was safe in terms of the risk of subsequent reactions on administration of these medications, and (b) if negative penicillin skin testing before the need for antibiotics resulted in the use of penicillin by the patient and referring physician. The first survey took place in 1989 and reviewed patients with negative skin tests to penicillin seen between 1983 and 1986. This survey was by written questionnaire. The second survey took place in 2001 and reviewed patients between 1993 and 1997 and was conducted by telephone. In the 1983-1986 survey, 41% of the 68 patients reviewed took antibiotics in the subsequent 3-6 years and 50% of these patients took penicillin. Between 1993 and 1997, of the 84 patients contacted, 36 patients (42.8%) had taken antibiotics and 17 of these patients took penicillin. Of the 19 patients who did not take penicillin, 13 patients expressed their reluctance to do so to the family physician, and in 6 cases it was reported by the patient that the physician thought it was safer to use an alternative antibiotic. Overall, only 6% of the total patients in both groups developed an adverse reaction to penicillin, in each case a morbilliform delayed rash occurred. No patient had more than one course of penicillin in the survey period. Elective skin testing for penicillin allergy without immediate challenge after negative tests is safe, associated only with a low incidence (6%) of morbilliform eruptions; however, despite negative skin tests and being informed that they would tolerate penicillin, 52% of patients still prefer to use alternative antibiotics.