The Importance of Screening for Inflammatory Bowel Disease in Patients with Psoriasis and Psoriatic Arthritis

Sir,

A strong association between psoriasis (PsO) and inflammatory bowel disease (IBD) has been established in the literature.[1] Not only are the relative risks of developing PsO significantly increased in patients with both Crohn's disease (CD) and ulcerative colitis (UC), but patients with PsO are at increased risk for developing IBD in the future. The coexistence of these diseases in patients has been further corroborated at the genetic level.[2] Despite this established association, there are a paucity of data demonstrating that clinicians regularly screen patients with PsO for IBD.

We herein present a case previously reported in the literature that underlines the importance of screening for IBD in patients with PsO.[3] A 53-year-old male with a history of PsO and psoriatic arthritis (PsA), initially well-controlled with secukinumab (on therapy for one year), was incidentally diagnosed with CD on a routine colonoscopy that was performed as part of his age-appropriate cancer screening – CT enterography demonstrated wall thickening, fatty replacement of the wall, and increased enhancement of the mucosa of the distal terminal ileum. The patient was transitioned to ustekinumab given the risk of CD exacerbation with IL-17 inhibition. Due to ustekinumab treatment failure after one year of therapy, he was subsequently transitioned to guselkumab. A year of treatment with guselkumab resulted in sustained therapeutic response of the patient's PsO/PsA (Psoriasis Area and Severity Index of 0) with incidentally noted radiographic improvement of his CD. Two years later, the patient reported complete endoscopic remission of his CD and remained asymptomatic clinically with regards to CD. His colonoscopy in August 2020 demonstrated no stigmata of recent bleeding in previously present erosions in the ileum and normally appearing cecum, ascending colon, transverse colon, and descending colon.

This case underlines the importance of screening patients with PsO/PsA for IBD. Feldman et al.[4] demonstrated that patients PsO reported an increased prevalence of Gastro-intestinal (GI) symptoms as compared to non-PsO controls (belly pain, feeling bloated, unintentional weight loss, blood in the stool, mucus in the stool, and diarrhea), and these symptoms were reported with increased frequency in patients with more severe PsO and concomitant PsA. Our patient was asymptomatic from a GI perspective and his CD was found incidentally. This case in conjunction with the epidemiologic and genetic data demonstrating the coexistence of PsO and IBD suggests that patients with PsO who are asymptomatic from a GI perspective should still be screened for IBD. Although the Joint American Academy of Dermatology–National Psoriasis Foundation (AAD-NPD) guidelines frequently refer to IBD in the context of considering various biologic therapeutics, screening all patients with PsO is not explicitly recommended.[5] We propose that inquiring about abdominal symptoms commonly encountered in patients with IBD should be routinely undertaken in all patients who are being treated for PsO/PsA, regardless of the severity of their skin and joint disease.[6]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.