A Case of Adalimumab-Induced Psoriasis in Crohnʼs Disease with Literature Review

Abstract

Results: A 29 y/o WF with 4 year history of Crohn's ileitis was treated with adalimumab for refractory disease. There was no past or family history of psoriasis. After 6 weeks of therapy, she developed a rash on her feet and palms. A skin biopsy demonstrated pustular psoriasis. Adalimumab was withdrawn and methotrexate begun with topical anti-psoriatic therapy. Tumor necrosis factor (TNF) inhibitors have been shown to paradoxically cause psoriasis (1). Cases of infliximab-induced psoriasis have also been described in patients with Crohn's disease (2). The mechanism by this class effect is poorly understood. It has been suggested that “psoriasis” may actually represent a form of cutaneous bacterial infection (keratoderma blenorrhagicum) or that the rheumatoid arthritis patients who developed psoriasis may have been misdiagnosed and actually had psoriatic arthritis (3). Harrison et al. (4) found an increased incidence of psoriasis in patients with rheumatoid arthritis treated with TNF inhibitors (1.04/1000 person years 95% CI 0.67/1.54) as compared to those treated with disease modifying anti-rheumatic drugs (0/1000 person years upper 97.5% CI 0.71). They also found a significantly higher incidence in adalimumab treated patients as opposed to those treated with infliximab and entanercept. Conclusion: TNF-induced psoriasis is a rare side effect which has been documented with entanercept, infliximab, and adalimumab. Defining this ill-defined mechanism may help us better understand the pathophysiology of the immune system and modify treatments in immune mediated diseases. 1. Matthews C, Rogers S, FitzGerald O. Development of new-onset psoriasis while on anti-TNF α treatment. Ann Rheum Dis 2006;65:1529–1530. 2. Sladden MJ, Clarke PJ, Wettenhall J. Infliximab-induced palmoplantar pustulosis in a patient with crohn's disease. Arch Dermatol 2007;143:1449. 3. Ritchlin C, Tausk F. A medical conundrum: onset of psoriasis in patients receiving anti-tumour necrosis factor agents. Ann Rheum Dis 2006;65:1541–1544. 4. Harrison MJ, Dixon WG, Watson KO, King Y, Graves R, Hyrich KC, et al. Rates of new-onset psoriasis in patients with rheumatoid arthritis receiving anti-TNF {alpha} therapy. Results from the british society for rheumatology Biologics register. Ann Rheum Dis 2008, April 2.