Beta-lactam antibiotics commonly cause immune thrombocytopenia. Cross-reactivity in patients with drug-induced immune thrombocytopenia has rarely been reported. In this study, we describe the case of a 79-year-old man who developed thrombocytopenia after receiving piperacillin–tazobactam for an acute exacerbation of chronic obstructive pulmonary disease, and he was successfully treated with meropenem and cefotiam. However, thrombocytopenia recurred after cefoperazone–sulbactam administration. This indicated that cross-reactivity of platelet-specific antibodies occurred between piperacillin–tazobactam and cefoperazone–sulbactam. However, the responsible drug structures remain unknown, requiring further investigation. Likewise, chemical structure similarities among beta-lactam antibiotics must be examined to determine the risk of immune thrombocytopenia in the clinical setting.

Beta-lactam antibiotics are a relatively common cause of immune thrombocytopenia. Cross-reactivity of them in patient with drug-induced immune thrombocytopenia is rarely reported. Here, we describe the case of a 79-year-old male patient experienced thrombocytopenia after receiving piperacillin-tazobactam for acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Fortunately, the patient was able to successfully challenge with meropenem and cefotiam. However, after the cefoperazone-sulbactam was administered, the patient experienced thrombocytopenia again. Therefore, there are cross-reactions of platelet-relative antibodies between piperacillin-tazobactam and cefoperazone-sulbactam. Although the exact responsible antibodies remain unknown and need further investigation, attention should be paid to the role of chemical structure similarities in determining the risk of immune thrombocytopenia among beta-lactams in the clinical setting.