Clinical features and outcomes of perianal disease in pediatric-onset Crohn’s disease: A comparative analysis according to age at diagnosis

This study aimed to investigate the clinical features, treatment responses, and outcomes of pediatric patients with Crohn’s disease (CD) and perianal disease (PD) in China, with a particular focus on age at diagnosis. We retrospectively analyzed 144 children diagnosed with CD between 2015 and 2024. Patients were divided into PD and non-PD groups and further stratified by age at diagnosis into very-early onset (VEO-IBD, < 6 years) and late-onset disease (LO; 6–18 years). The clinical, endoscopic, and genetic data were compared between the groups. The overall prevalence of PD was 57/144 (39.58%). VEO-IBD cases accounted for 44/144 (30.56%) of cases, of whom 22/44 (50.00%) had concurrent PD; among these VEO-PD patients, the monogenic mutation rate was 17/22 (77.27%), predominantly involving IL-10RA. In the full cohort, PD was associated with increased colonic involvement (25/57 [43.86%] vs. 17/87 [19.54%], P < 0.05), greater disease severity (severe PCDAI: 25/57 [43.86%] vs. 20/87 [22.99%], P < 0.05), and lower clinical remission rates (41/57 [71.93%] vs. 83/87 [95.40%], P < 0.05). In the LO subgroup, patients with PD were treated with biologic agents significantly earlier, with clinical remission of perianal lesions reaching 30/35 (85.71%). VEO-IBD with PD was associated with monogenic mutations, greater disease activity, and lower clinical remission. VEO-PD had poorer outcomes than VEO-IBD without PD, although mortality was similar. In selected monogenic VEO-IBD patients, thalidomide and/or HSCT may be individualized options, but thalidomide should not be generalized to all VEO-IBD.