A DELAYED DRUG RASH IN A PATIENT WITH ULCERATIVE COLITIS: INFLIXIMAB-INDUCED PSORIASIS.

Abstract

<h3>Introduction</h3> Infliximab, a Tumor Necrosis Factor (TNF)-α antagonist, can rarely lead to paradoxical psoriasis even though infliximab can be used to treat psoriasis. We present a case of TNF-α-inhibitor-induced psoriasis. <h3>Case Description</h3> An 18-year-old-female with ulcerative colitis on infliximab was evaluated after developing a one-month history of generalized erythematous papules and plaques with scale (Fig 1A) sparing her face and neck. She had recently received a course of azithromycin 2 days prior and had started oral contraceptives (OCPs) a month prior. She had been on infliximab every 2 months for the last year and had received the last infusion a month prior to development of the rash. She was not on any over-the-counter medications or supplements. The rash did not improve with systemic steroids or low-dose antihistamines. A punch biopsy revealed acanthosis, parakeratosis, dilated blood vessels with surrounding mixed inflammatory infiltration with thinning of the suprapapillary epidermal plates (Fig 1B) consistent with psoriasis. She was recommended to avoid further TNF-α inhibitors and was started on ustekinumab. The psoriasis was treated with triamcinolone 0.1% cream using wet dressing technique and resolved within 2 months. The patient continued with OCPs and declined an azithromycin challenge. <h3>Discussion</h3> Most side effects from TNF-α inhibitors are observed during the first six months of use including: injection site reactions, cutaneous infections, immune-mediated complications (psoriasis and lupus), and even skin cancers. Identifying the difference between classic psoriasis and drug-induced psoriasis may be challenging due to the variable clinical and histopathological features.