Intertriginous/Periorificial Dermatoses in Patients With IBD on Anti-TNFα: Relative Abundance of Staphylococcus Aureus Within the Lesion Microbiota and Clinical Correlation (micSPIDER).

The main objective of this study is to evaluate the change in the relative abundance of S. aureus within the lesion-site skin microbiota in SPIDER patients (change between inclusion and 6 months), and to assess whether this change in S. aureus abundance is associated with a favorable (or unfavorable) evolution of the wounds over the same period.

Inclusion Criteria: * Diagnosed with IBD * Receiving anti-TNFα therapy * WITH skin lesions such as crusted rhinitis ± inflammatory alopecic scalp lesions ± intertrigo of the large skin folds ± folliculitis (Scalp and Periorificial Inflammatory DERmatis, SPIDER) * Parental consent for minor patients * Patient who has provided free and informed consent and has signed the consent form * Patient affiliated to or beneficiary of a health insurance system Exclusion Criteria: * Patients for whom a change in therapy is planned within 6 months (SPIDER+). * Patients receiving antibiotics (systemic or topical) at the time of enrollment, with a window of at least 1 month. * Patients who have participated in a clinical drug trial within the last three months * Patients currently in an exclusion period determined by a previous study * Patients under legal guardianship, conservatorship, or trusteeship * Patients who refuse to sign the informed consent form * Pregnant or breastfeeding patients.