This study is a secondary analysis of the Adelphi Real World Alopecia Areata II United States Disease Specific Programmes database. This database contains data from a cross-sectional study capturing linked physician and patient survey data for dermatologists who treat alopecia areata and patients diagnosed with alopecia areata in the United States. The retrospective analysis of these data will evaluate experiences of patients and dermatologists receiving/prescribing ritlecitinib for severe alopecia areata in the United States. Specifically, the study will describe characteristics of patients who received ritlecitinib for severe alopecia areata, including demographics, clinical characteristics at the time of starting ritlecitinib, and their alopecia areata-related treatment history. The study will also report dermatologist satisfaction with treatment and change in the patient's alopecia areata severity and disease activity from the start of ritlecitinib to different time points on treatment.

Aged 18 years or older with severe alopecia areata

Patients with severe AA treated with ritlecitinib by dermatologists in the US.

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.