The diagnostic value of intradermal tests with penicilloyl-dextran and aspiryl-polylysine.

Intradermal tests (i.d.t.) with penicillin (P) and penicilloyl-dextran (P-Dex) were performed in 32 penicillin allergic patients and in 37 controls with allergy to other drugs. The incidence of the positive i.d.t. was much higher in the group of penicillin allergy of immediate type (17 of 18 patients) than in the group of penicillin allergy of half-late or late type (4 of 14 cases). I.d.t. with P and P-Dex were concordant in 75% of cases. Among 28 patients with penicillin allergy tested with both reagents, i.d.t. positive only to P-Dex were found in two cases. The utilisation of i.d.t. with P-Dex or penicilloyl-polylysine (PPL) in penicillin allergy furnishes, therefore, only very modest additional information besides that furnished by i.d.t. performed with plain penicillin. I.d.t. with aspiryl-polylysine (APL) were performed in 23 patients with aspirin allergy/intolerance and in 60 controls with allergy to other drugs. 70% of the individuals with aspirin allergy and 27% of the patients with allergy to other drugs showed positive i.d.t. to APL. Although the specificity of i.d.t. with APL in aspirin allergy seems lower than that of i.d.t. with P-Dex and PPL in penicillin allergy, a positive cutaneous test with APL may constitute an important argument for the allergic nature of an aspirin adverse reaction evoking an allergic mechanism.