Digestive Evolution of Children With Crohn's Disease or Ulcerative Colitis Whose Anti-TNFα Treatment Was Switched to Ustekinumab Due to Paradoxical Psoriasis,

Inflammatory bowel diseases (IBD) include Crohn's disease (CD) and ulcerative colitis (UC). They cause abdominal pain and chronic diarrhea and/or rectal bleeding, which can lead to weight loss and malnutrition. IBD affects people of all ages but usually appears before the age of 30, most often between the ages of 14 and 24. Childhood IBD is generally considered to be more progressive than adult IBD. Although there is no cure for IBD, many medications can help reduce inflammation and relieve IBD symptoms. Anti-TNF drugs (infliximab and adalimumab) are used early in high-risk patients or when standard treatments have failed. Cutaneous side effects are common in pediatrics (\>10%), primarily psoriasiform eruptions (41%), often exudative, affecting skin folds and scalp, recurrent skin infections (20%), and eczematous eruptions (10%). Only 5% of patients need to discontinue treatment due to these side effects. In such cases, the recommended treatment is ustekinumab (European guidelines). While this treatment has been described as effective in patients who have failed anti-TNFα therapy, little data is available on the gastrointestinal and dermatological outcomes of patients on anti-TNFα therapy who switch to ustekinumab for dermatological reasons.

Inclusion Criteria: 1. Patients capable of giving their non-opposition 2. Patient \ 18 years 2. Diagnosis of IBD not confirmed 3. Discontinuation of anti-TNFα for a cause other than psoriasis