The systemic treatments for moderate to severe atopic dermatitis (AD) are limited to phototherapy and cyclosporine with the risks respectively of either carcinoma, or hypertension or nephropathy.

Methotrexate was effective in 75% of moderate to severe AD patients with good tolerance in an open retrospective study.

We want to confirm our observations: a non inferiority multicenter clinical trial, methotrexate versus cyclosporine, will be conducted in 100 patients for 24 weeks.

Inclusion Criteria:

• Patients aged > 18 years old.
• Both genders eligible for study.
• Moderate to severe AD.
• Scorad > 15.
• Participants must use a contraceptive method during the trial and for 3 months after the end of the trial for female and 5 months for male participants.
• Participants must be able to understand and sign the Informed Consent, and comply with all aspects of the protocol.
• Patients must be registered in a social security system or with a health insurance coverage.

Exclusion Criteria:

• Pregnant or lactating women.
• Evolutive skin disease.
• Patients with a clinically significant disease (chronic, recurrent or active).
• Systemic corticotherapy or immunosuppressive treatment during the previous month, or local corticoid the week before the inclusion.
• Contra-indication to methotrexate and cyclosporine.
• Exposure to phototherapy: cumulative dose > 2000 J/cm2.
• Patients deprived of their civic rights, in custody, or subject to a tutorial, judiciary or administrative decision.
• Patients under a protection measure.
• Patients in a critical medical situation.
• Patients with a personal situation evaluated by the investigator as unable to give optimal participation to the study, or where the study could constitute a risk for the patient.