Bullous pemphigoid induced by ustekinumab: a case report.

A possible case of bullous pemphigoid (BP) that developed during treatment with ustekinumab is reported. Ustekinumab is a human monoclonal antibody found in pathologies such as psoriasis, which works by inhibiting the activity of interleukin-12 and interleukin-23. We describe the case of a 75-year-old woman who presented with new onset of erythematous and bullous lesions 5 days after receiving a fifth dose of ustekinumab. The patient was treated with corticosteroids and dapsone, whereupon the lesions disappeared. Ustekinumab was withdrawn. Currently the patient remains asymptomatic. In addition, the histopathological and immunofluorescence findings confirmed the diagnosis of BP. Three causality algorithms were applied and revealed a probable causal relationship. There may be a causal relationship between the use of ustekinumab and BP. This association should be taken into account by physicians when prescribing and reviewing drug therapies. © European Association of Hospital Pharmacists 2021. No commercial re-use. See rights and permissions. Published by BMJ.