EVALUATION OF ADVERSE CUTANEOUS REACTIONS TO AMINOPENICILLINS WITH EMPHASIS ON THOSE MANIFESTED BY MACULOPAPULAR RASHES

We assessed 195 subjects with histories of adverse reactions to aminop enicillins, using 1) skin tests with penicilloyl polylysine (PPL), min or determinant mixture (MDM), benzylpenicillin (PG), amoxicillin, and ampicillin (read after 20 min and 48 h); 2) patch tests with PG, amoxi cillin, and ampicillin; and 3) RAST for penicilloyls G and V. Oral cha llenges with ampicillin, amoxicillin, and penicillin V were administer ed to 34/60 patients reporting maculopapular reactions. Immediate hype rsensitivity (IH), in most cases for both penicillin and aminopenicill ins, was diagnosed (based on skin tests, RAST, or both) in 35 subjects who had suffered anaphylactic shock, or urticaria, angioedema, or bot h urticaria and angioedema. Thirty-three of the 60 subjects reporting maculopapular reactions presented delayed intradermal and patch-test p ositivity, indicating delayed hypersensitivity (DH), for ampicillin an d amoxicillin, and three were also positive for PG. Diagnoses were con firmed with oral challenges in 18/33. The remaining 27/60 were negativ e in all allergologic tests, with oral-challenge confirmation in 16. O ur findings highlight the importance of the amino group in DH to amino penicillins. Moreover, the mean time interval between the last reactio n and our tests was significantly (P < 0.01) longer in DH subjects (54 .96 months) than in those with IH (18.62 months), suggesting that the time of testing is less important in cases of DH.