Back to basics: the respiratory management of Duchenne muscular dystrophy

Beta-lactam (BL) antibiotics are among the most prescribed drugs globally but can provoke hypersensitivity reactions which can lead to incorrectly labelling as ‘allergy’. Data on prevalence and incidence of drug hypersensitivity reactions (DHRs) are limited, especially in the pediatric age. It is important to assess subjects with history of hypersensitivity reactions to BL as up to 70% are not allergic based on diagnostic test results. Laboratory tests for identifying children who are allergic to drugs have low diagnostic accuracy and predictive value. The gold standard to diagnose DHR is drug provocation test (DPT). DHRs are classified as immediate or nonimmediate/delayed reactions. Mild delayed cutaneous reactions including maculopapular rashes and urticaria/angioedema are common reactions in children and often occur in the setting of viral infections. In mild cutaneous delayed reactions, some clinicians suggest performing only DPT because of its high negative predictive value, without skin testing and serum IgE measurement while other suggest SPT and/or specific IgE to culprit drug if patient/caregiver cannot provide a detailed description of the previous reaction. Aim: to investigate the proportion of positive oral provocation tests in children labeled as BL antibiotic allergy. Direct oral challenge was performed in patients with history of benign rash associated with beta-lactam antibiotic. Because detailed description of suspected allergic reaction could not be provided from all caregivers, all patients went specific IgE to amoxicillin and/or basophil degranulation test to culprit drug which was negative. 19 patients were included, average age 6 years and 1 month. In 17 patients suspected allergic reaction was caused by amoxicillin (AMX); 8 of which in combination with clavulanic acid, one with phenoxymethylpenicillin and one with cephalexin. A DPT involved open 3-step graded oral provocation test with AMX, time interval between the doses was 2h. The patients were monitored for 24h after challenge and were discharged with instructions to call in the event of a delayed reaction. After DPT there was no reaction in 89% of patients, one patient developed benign rash and one drug-induced enterocolitis syndrome. BL antibiotics can be safely readministered to children with history of benign rash to beta-lactams using graded oral challenge in medically supervised settings if spIgE is negative even if uncertain history. It is important to establish a correct diagnosis of BL antibiotic allergy since using alternative non–β-lactam antibiotics in these patients leads to higher healthcare costs and adverse events.