The purpose of this study is to learn about the safety and effects of Abrocitinib in the real-life clinical setting given for the treatment of moderate to severe atopic dermatitis. Atopic dermatitis, or AD, is a long-lasting disease that causes inflammation, redness, and irritation of the skin.

This study is seeking participant who are older than 18 years with moderate-to-severe chronic AD. Participants must have no underlying medical conditions that prevent them from taking Abrocitinib.

All participants in this study will receive Abrocitinib as a tablet once daily. They can take Abrocitinib and use medicated topical treatment for AD at the same time.

We will examine the experiences of patients receiving the study medicine. This will help us determine if the study medicine is safe and helps in treating AD.

Participants will take part in this study for 24 months. During this time, they will visit the study clinic about 5 times (about 1 time every 4 to 6 months).

Inclusion Criteria:

• Patients older than 18 years of age at inclusion.
• Patients with clinical diagnosis of moderate-to-severe chronic atopic dermatitis (also referred to as atopic eczema) at inclusion according to the investigator and eligible for abrocitinib according to its marketing approval.
• Patients that have been informed of the study procedures and have signed the consent.

Exclusion Criteria:

• Patients for whom abrocitinib is contraindicated.
• Patients unable to follow and respect the study procedures and judged inapt to respond to the questions required for the study due to linguistical, psychological, social, or geographical reasons.
• Patients not affiliated to the French social security system.
• Patients deprived of liberty, under guardianship, or unable to provide oral consent.
• Patients participating in a clinical study assessing a medicinal treatment (patients can participate in registries and observatories).

Patients with a diagnosis of moderate to severe atopic dermatitis for whom the dermatologist has decided to initiate a treatment with Abrocitinib

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.