S4904 Leukocytoclastic Vasculitis in a Patient With Crohn’s Disease on Anti-TNF-α Therapy

Introduction: Anti- tumor necrosis factor (TNF)-α therapies are common agents used in the treatment of inflammatory bowel disease (IBD). They are, however, associated with adverse effects (AEs), including infections, arthropathies, and rashes. Clinicians must also remain vigilant for a wider range of additional, lesser-known AEs in the management of IBD patients on anti-TNF-α agents. Case Description/Methods: An 81-year-old man living in India with stricturing ileocolonic and fistulizing perianal Crohn disease controlled on anti-TNF-α therapy presented with a new-onset rash. Eighteen months prior, the patient had been diagnosed with IBD and started on adalimumab. Dermatologic exam showed diffuse, bilateral lower extremity erythematous papules and coalescing plaques which were palpable and non-blanching. Skin biopsy was undertaken which revealed small-vessel neutrophilic vasculitis with red cell extravasation, consistent with leukocytoclastic vasculitis (LCV). The patient’s adalimumab therapy was discontinued, and a transition was planned to anti-IL-23 therapy with risankizumab, methotrexate and topical triamcinolone acetonide. Discussion: LCV is a rare small-vessel vasculitis mediated by immune complex deposition in postcapillary venules. It has been associated with a variety of conditions including infections, autoimmune processes, medications, and malignancies. LCV often presents with palpable purpura predominantly in dependent locations, such as the lower extremities, and can be associated with fever and renal involvement. Evaluation consists of thorough history-taking, medication review, and laboratory studies to screen for contributing pathologies and internal organ involvement. An essential step in LCV evaluation is skin biopsy to confirm the diagnosis and differentiate the condition from other rashes. Management involves addressing any underlying process. In cases of anti-TNF-α-associated LCV discontinuation of the medication is recommended, as well as a short course of steroids. Severe or multi-organ involvement requires more aggressive immunosuppressive therapy. While re-challenging with another anti-TNF-α therapy may be considered, the preferred approach for ongoing IBD management in these patients is to switch to a non-TNF-α biologic. Although not as common as other dermatologic AEs of biologic therapies, clinicians should keep LCV on their differential diagnosis when evaluating rashes in IBD patients to promptly identify and implement appropriate management for these cases.