Incidence of systemic reactions to skin tests and drug challenge tests

Abstract

Study objectiveLocalised and systemic immediate-type reactions during allergological in vivo tests for drugs are a rare occurrence. However, in high-risk patients, immediate intensive care support is required. We sought to evaluate the risk of systemic reactions induced by skin tests and drug challenge tests. Patients and methodsWe investigated all immediate-type reactions that occurred during allergological testing in the outpatient allergo-anaesthesia unit of the Cluj Clinical Emergency County hospital from 2007 until August 2017 in order to identify patients presenting localised and systemic immediate-type hypersensitivity reactions. ResultsDrugs were tested in 2139 patients using in vivo allergological tests. In total, 261 patients presented positive skin prick-tests and 535 presented positive intradermal tests. One patient presented grade II anaphylaxis during intradermal testing with antibiotics (amoxicillin) and one patient presented grade III anaphylaxis induced by intradermal testing of midazolam. We performed 553 drug challenge tests. Twenty-nine patients presented positive drug challenge tests. One patient presented grade III anaphylaxis during a drug challenge test with etoricoxib. Grade III anaphylaxis was also induced in a patient challenged with clindamycin. Four of 29 patients with a positive drug challenge test developed grade II anaphylaxis, while 23 of 29 presented grade I anaphylaxis. Two of 29 positive drug challenge test patients experienced more severe reactions during testing compared with previous hypersensitivity reactions, while 8 patients presented less severe reactions. ConclusionThough low, the risk of induction of severe systemic reactions during allergological skin tests and drug challenge tests nevertheless remains present.