Results of comparative skin tests with penicilloyl-polylysine and penicillin in patients with penicillin allergy

Abstract

Intracutaneous tests in 120 patients with a previous history of penicillin allergy yielded positive results with penicilloyl-polylysine in 37 per cent and penicillin G in 15 per cent of patients tested up to twenty years after their reactions. There was an inverse relationship between the incidence of positive skin reactions with either reagent and the time interval at which the tests were performed following an allergic reaction. A higher incidence of positive responses resulted with penicilloyl-polylysine at all time periods, and this difference was highly significant for the period of three months to three years. Of patients with allergic reactions to penicillin tested during the initial three month period, 78 per cent demonstrated skin sensitivity to penicilloyl-polylysine. Since a significant number of patients have negative reactions during this early period, this reagent cannot be used to exclude penicillin as the etiologic agent in an allergic reaction. Marked skin responses to penicillin G, which occurred exclusively following immediate systemic reactions, may not be entirely due to the penicilloyl-determinant group. Alternative possibilities are discussed. It appears that skin test responses to penicillin G may be a more specific index of anaphylactic sensitivity than are cutaneous responses to penicilloyl-polylysine. Evidence is presented to substantiate the immunologic pathogenesis of large local reactions to intramuscularly administered penicillin.