Ustekinumab-induced drug eruption: Insights into acquired ichthyosis

Ustekinumab, a fully human monoclonal IgG1 antibody, is widely used for treating inflammatory conditions, including ulcerative colitis, among other indications such as Crohn’s disease and psoriasis. While generally well-tolerated, it may cause adverse effects, including rare dermatological reactions. Acquired ichthyosis, a condition characterized by diffuse scaling and xerosis, is typically associated with systemic diseases or medications yet remains infrequently linked to biologic therapies. This case presented a rare instance of ustekinumab-induced acquired ichthyosis, an uncommon drug reaction that may need consideration in clinical practice, particularly, as the use of biologics continues to expand.