S2273 A Drug Reaction to Ustekinumab in a Patient With Crohn’s Disease

Abstract

INTRODUCTION: In 2016, ustekinumab became the newest biologic with FDA approval for treatment of Crohn’s disease (CD). It is a human monoclonal antibody that binds to the p40 subunit of interleukin-12 (IL-12) and interleukin-23 (IL-23). It is overall very well tolerated. Dermatologic complications are relatively uncommon. During post-marketing approval, there have been reports of pustular psoriasis, erythrodermic psoriasis, pseudolymphomatous drug eruption, and eczematous drug eruption in psoriasis patients. CASE DESCRIPTION/METHODS: A 42 year old man with a complicated 25 year history of ileocolonic CD, prior ileocolic resection for a colonic stricture, and partial left hemicolectomy for a colo-cutaneous fistula and abdominal abscess while on adalimumab presented with abdominal pain after 4 years without follow up. Imaging and colonoscopy showed ileitis and an enterocolonic fistula. Ustekinumab was started. 2 days later, he developed a pruritic erythematous blistering skin rash on his neck, arms, and trunk without mucous membrane involvement or fever. Skin biopsy revealed a hypersensitivity skin reaction, which resolved in 10 days. He received 4 days of premedication with acetaminophen, famotidine, prednisone, and diphenhydramine before his maintenance dose of 90 mg subcutaneously without any reaction. He continues to be on the drug with good effect. DISCUSSION: Only a few case reports of drug eruptions to ustekinumab exist in the literature, and all are in patients treated for psoriasis. One patient had urticaria 3 weeks after their 4th dose of ustekinumab and subsequent doses. They likely formed drug antibodies and had a change in therapy. Another patient had multiple painless indurated pink papules and plaques on their trunk 9 days after the 1st dose. Biopsy showed a lymphomatoid drug reaction, which resolved spontaneously after 2 months. Another patient had a psoriasiform eczematous drug eruption on their trunk and limbs 3 days after the 2nd injection; it resolved in 2 weeks with topical steroids. This is the first case report of a drug eruption in a patient with ustekinumab for CD. Management varies. Antibody formation requires discontinuation of therapy. If we extrapolate from anti-TNF literature, non-antibody reactions may be able to be managed with short term topical or systemic therapy and without necessarily discontinuing the drug. Treatment should occur on a case-by-case basis because reported dermatologic reactions are so few in number.