Assessment of a self-designed protocol on patients with adverse reactions to beta-lactam antibiotics

Suspected adverse reactions to beta-lactam antibiotics are the most frequent reason for consultation in relation WMH drug allergy. Because of their therapeutical usefulness and wide use, we developed a protocol for confirmation or exclusion of this type of allergy. The proposed protocol is based on clinical, causal and laboratory criteria that are used to assign scores from 0 to 9 points. Patients with scores between 0 and 3 are considered to be highly prone to beta-lactam antibiotic allergy and are given an alternative therapy that is selected by applying skin provocation tests (SPT). Those with a score of 9 points are excluded. Finally, those with scores between 4 and 8 are subjected to skin tests with 5 antigens (penicillin G, ampicillin, cephalothin, Penkit PPL and Penkit MDM); if they give negative results they are subsequently subjected to oral provocation with beta-lactam antibiotics. In this work we report the results obtained from 150 patients analysed for 28 variables altogether. The results allowed us to rule out adverse reactions in 94 patients. Only 9 individuals yielded positive skin tests, and only one gave a positive oral provocation (bronchospasm, 6 hours after subjection to the test). The usefulness of the proposed protocol, the profitability of the test applied and the mechanisms involved are assessed.