A systematic review: can one prescribe carbapenems to patients with IgE-mediated allergy to penicillins or cephalosporins?

BACKGROUND Cross-reactivity between penicillins or cephalosporins and carbapenems is anticipated as all have a beta lactam ring. However, the true incidence of immunoglobulin (Ig)E-mediated cross-reactivity is not known. METHODS A systematic review was conducted to collect and combine all published data on children and adults reported to have a clinical history of IgE-mediated hypersensitivity to a penicillin and/or cephalosporin who were subsequently given a carbapenem. Reactions were classified as proven, suspected, or possible IgE-mediated and non-IgE-mediated. RESULTS Ten studies and 12 case reports describing 854 participants fit the study criteria. For patients with previous proven, suspected, or possible IgE-mediated penicillin reactions (N = 838), the incidence of any type of suspected hypersensitivity reaction to a carbapenem was 36/838 (4.3%; 95% confidence interval [CI], 3.1%-5.9%) and the incidence of proven (1/838), suspected (0/838), or possible (19/838) IgE-mediated reactions was 20/838 (2.4%; 95% CI, 1.6%-3.7%). Of the subset of patients with positive penicillin skin tests (n = 295), only 1 had a hypersensitivity reaction (0.3%; 95% CI, .06%-1.9%), and this was a possible IgE-mediated reaction. For patients with previous proven, suspected, or possible IgE-mediated cephalosporin reactions (N = 12), the incidence of any type of hypersensitivity reaction to a carbapenem was 3/12 (25%); this included 2 non-IgE-mediated reactions and 1 possible IgE-mediated reaction. CONCLUSIONS The cross-reactivity between penicillins and carbapenems for IgE-mediated reactions is very low, but caution is still advised. Cross-reactivity rates may be higher between cephalosporins and carbapenems; however, minimal data are available.