The prevalence of cross

Cross-reactivity between penicillin and cephalosporin is of crucial concern among patients who have had a previous allergic reaction to penicillin, and cephalosporin is the first choice for their diseases. There is very little evidence concerning the prevalence of cross-reactivity in the Asian population. This study aims to explore the cross-reactivity between penicillin and cephalosporin in the Asian population. This study included patients who were registered at Lampang Hospital from January 2011 to January 2018. Only patients who were prescribed penicillins and cephalosporins at least once as recorded in the electronic medical records (EMR), were included. Patients having penicillin and cephalosporin allergies were defined as those who were diagnosed in the EMR as allergic to drugs in the penicillin/ cephalosporin groups, in either the probable or definite categories with respect to the Naranjo’s algorithm. Cross-reactivity is defined as patients who were diagnosed as being allergic to both penicillin and cephalosporin. Data about characteristics and types of allergic reactions (type I & IV) were obtained from the EMR. A total of 13,959 patients were included in the study. Of these, 99 penicillin-allergic and 13,860 non-penicillin-allergic patients were identified. The prevalence of cross-reactivity among patients with a history of penicillin allergy was 8.1%. Results showed high cross-reactivity rates among patients with type 1 (16.7%) and type 4 (13.3%) hypersensitivity, in relation to other allergic manifestations (3.4%). This study raises the possibility that cross-reactivity reported in previous research may differ from that in the Asian population. More Asian-based studies are needed to evaluate this cross-reaction so that this information can further assist medical professionals in clinical decision-making