A 12-year-old boy with no family history of inflammatory bowel disease (IBD) or psoriasis was diagnosed with Crohn's disease (CD) and simultaneously developed a localized umbilical rash. At age 14 years, infliximab was administered to treat the CD; however, complete remission was not achieved, and his umbilical rash did not improve with infliximab. His gastrointestinal symptoms occasionally recurred despite escalating infliximab to 5 mg/kg/day every 4 weeks. At age 16 years, there was a further recurrence of CD with infliximab, and his umbilical rash persisted (Figure 1a). Histopathological examination findings confirmed a diagnosis of psoriasis (Figure 1b). The psoriatic umbilical lesion improved with ustekinumab, whereas the CD did not (Figure 1c). Following a switch to risankizumab 20 weeks after having started ustekinumab, the CD subsequently improved. Our patient responded less favorably to infliximab than is usual for patients with CD, and relapse requiring a switch to other biological agents occurred more quickly. IBD is more commonly complicated with psoriasis compared with healthy controls.1 Similarly, it has been reported that patients with psoriasis are more likely to develop IBD than healthy controls.2 Based on these findings, the pathogenesis of psoriasis and IBD is considered to be closely related. The difference in efficacy between antitumor necrosis factor alpha (TNF-α) and interleukin (IL)-23 agents in CD remains unclear; in psoriasis, however, a network meta-analysis suggests that infliximab, anti-IL-17 agents, and certain anti-IL-23 agents (risankizumab and guselkumab) achieve higher PASI 90 response rates than ustekinumab and several other anti-TNF-α agents (adalimumab, certolizumab, and etanercept), although the superiority of anti-IL-23 agents over all anti-TNF-α agents, including infliximab, has not been conclusively established.3 It remains unclear whether the effectiveness of biological agents for IBD differs depending on whether or not psoriasis is a complication. Our patient's psoriatic rash, located in the umbilical region, is not an uncommon presentation. A recent Japanese cohort study reported that approximately one quarter to one third of their study population had umbilical psoriasis.4 Moreover, it is important to diagnose psoriasis in umbilical lesions.5 Our patient's umbilical psoriasis does not represent a paradoxical anti-TNF reaction as it occurred prior to anti-TNFα agents administration. To determine whether concomitant psoriasis and IBD influence the treatment choice and clinical course, accumulation of additional cases is warranted. YF collected and analyzed the data, and drafted and revised the initial manuscript; KI, TS, KI, and HS interpreted the data and critically revised the manuscript for important intellectual content. All the authors have read and approved the final manuscript and agree to be accountable for all aspects of the work. Written informed consent was obtained from the patient's parents/guardians for the publication of this Images in Pediatrics and its accompanying images. We thank Editage (www.editage.com) for the English language editing. No funding was received in relation to this article. The authors declare no conflict of interest. The data that support the findings of this study are available from the corresponding author upon reasonable request.
Fujita et al. (Thu,) studied this question.