Biological treatments (BT) are commonly prescribed to treat chronic inflammatory diseases in children. Paradoxical reactions during treatment with a biological agent can be defined as the appearance or exacerbation of a pathological condition that usually responds to this class of drug while treating a patient for another condition. Limited data are available in children treated by BT on cutaneous paradoxical reactions, or any other cutaneous adverse events occurring during treatment. On the contrary, dermatologists tend to see and manage increasing numbers of cutaneous adverse events, including paradoxical reactions. The aim of this project is to describe the incidence of cutaneous adverse events, including cutaneous paradoxical reactions, occurring in the pediatric population, during a treatment by BT given for a chronic inflammatory disease.

Inclusion Criteria:

• Children under 18 years old
• Children treated by biotherapy among : Adalimumab, Golimumab, Infliximab, Ustekinumab, Etanercept, Tocilizumab, Canakinumab, Anakinra, Abatacept.
• Children treated for a chronic inflammatory disease (rheumatologic, gastro-enterologic, dermatologic and ophthalmologic)
• Children treated in the CHU of Amiens
• Parental consent signed

Exclusion Criteria:

• Age > 18 ans

• For the children already under biological therapy for an inflammatory chronic disease : they will benefit of one dermatologic consultation at any time of their treatment. Other consultations can be asked by the patient or by his parents if any skin manifestation appears beside the planned date of the consultation.
• For the children who are going to be treated by a biological therapy : they will benefit of one dermatologic consultation BEFORE the onset of the biological therapy, and on other one at 4 months afetr the beginning of the treatment. Other consultations can be asked by the patient or his parents if any skin manifestation appears beside the planned dates of both consultations.