INTRODUCTION
Psoriasis and psoriatic arthritis are observed at a frequency about eight times higher among patients with Crohn’s disease (CD) than in the general population. Accordingly, a number of recent studies have revealed psoriasis and psoriatic arthritis as independent risk factors for the development of CD.1 The link between these complex immune mediated inflammatory diseases is poorly understood; however, scientists postulate that it may be related to shared genetic abnormalities and common cytokine-driven inflammatory pathways (such as the interleukin (IL)-23 and Th17 pathways).2
While psoriasis, psoriatic arthritis, and CD all share a common central pathogenesis pathway and a wide overlap of treatment regime, discrepancies still exist. These differences are highlighted by variabilities in the effectiveness of certain immunomodulating agents, such as etanercept. Etanercept is a recombinant dimer of human tumor necrosis factor (TNF) receptor proteins bound to human IgG1 and is an effective treatment for psoriasis, among other autoimmune diseases.3 However, etanercept has been shown to be ineffective in CD, due to its inability to induce T-cell apoptosis in the intestinal mucosa.4 Ustekinumab, on the other hand, has been shown to be particularly effective for the management of both CD and psoriasis due to its targeting of IL-12 and IL-23.2,5
While psoriasis, psoriatic arthritis, and CD all share a common central pathogenesis pathway and a wide overlap of treatment regime, discrepancies still exist. These differences are highlighted by variabilities in the effectiveness of certain immunomodulating agents, such as etanercept. Etanercept is a recombinant dimer of human tumor necrosis factor (TNF) receptor proteins bound to human IgG1 and is an effective treatment for psoriasis, among other autoimmune diseases.3 However, etanercept has been shown to be ineffective in CD, due to its inability to induce T-cell apoptosis in the intestinal mucosa.4 Ustekinumab, on the other hand, has been shown to be particularly effective for the management of both CD and psoriasis due to its targeting of IL-12 and IL-23.2,5
CASE REPORT
We report a case of a 37-year-old obese male with a 20-year history of psoriatic arthritis with cutaneous involvement who was treated with etanercept (50 mg weekly) after discontinuation of infliximab, due to insurance requirements. The patient presented with a 2-month history of moderate to severe left upper quadrant pain radiating to the periumbilical area and a 4-month