A 40-year-old man with severe psoriasis unresponsive to methotrexate is started on a biologic. He develops recurrent upper respiratory tract infections. Which biologic most likely causes a predisposition to Candida infections due to its specific mechanism?

• A Adalimumab (anti-TNF-alpha)
• B Ustekinumab (anti-IL-12/23 p40 subunit)
• C Ixekizumab (anti-IL-17A, but same mechanism as secukinumab)
• D Secukinumab (anti-IL-17A) ✓

Explanation

IL-17A plays a critical role in mucosal defense against Candida albicans. Anti-IL-17A biologics (secukinumab, ixekizumab) and the IL-17 receptor blocker brodalumab predispose to mucocutaneous candidiasis. This is distinct from anti-TNF agents which predispose to mycobacterial/fungal systemic infections and reactivation of latent TB. Ustekinumab (anti-p40, blocking both IL-12 and IL-23) carries lower Candida risk. The question specifies Candida predisposition, pointing to the IL-17 blockade mechanism.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.