Ustekinumab in the Treatment of Erythema Nodosum with Underlying Crohn’s Disease: A Case Report

Erythema nodosum (EN) is a septal panniculitis characterized by raised, tender, red or purple lesions with a diameter of 1-5 cm. It is commonly treated with corticosteroids and can be an extra-intestinal manifestation of Crohn’s disease (CD). CD can be treated with ustekinumab, a monoclonal antibody that targets the p-40 subunit of the interleukin-12 (IL-12) and interleukin-23 (IL-23). A 78-year-old woman with erythema nodosum and Crohn’s disease presented with multiple erythematous nodules, which had been recurring on both of her legs for decades. The patient had failed many traditional EN treatments and was prescribed off-label ustekinumab, resulting in resolution of EN. This finding suggests that ustekinumab may be a potential treatment for EN in patients who also have CD.