The study series consists of three studies with the aim to assess the incidence, prevalence, risk factors, comorbidities and management of patients with alopecia areata in Czech Republic based on the patients and registry of a dermatology clinic of a metropolitan hospital.

The first study will aim to identify the incidence and prevalence of alopecia areata in the dermatology clinic of a metropolitan teaching hospital between 1/1/2011 and 31/12/2020

The second study will assess (1) the epidemiology of autoimmune and atopic diseases in patients with alopecia areata, (2) the presence of possible risk factors responsible for the onset/relapse/exacerbation of alopecia areata, (3) the levels of vitamin D and various autoantibodies,particularly thyroid autoantibodies and (4) the variety, duration, efficacy and safety profile of treatment modalities used in our hospital for the management of alopecia areata from 15/10/2021 to 14/10/2022.

The third study will monitor the monthly oscillations of vitamin D and thyroid-autoantibodies of patients with new-onset/relasping or exacerbating alopecia areata for six months, between 15/10/2021-14/10/2022 in order to observe if changes in levels of vitamin D and thyroid-antiantibodies are associated with severity and prognosis (worsening or improvement) of alopecia areata

Inclusion Criteria:

• All patients visiting our clinic with a dermatologic condition between 1/1/2011-31/12/2020
• For the second study, only patients with histologic/dermatoscopic diagnosis of new-onset/relapsing/peristent-untreated alopecia areata, presenting to our clinic between 15/10/2021-14/10/2022 are included.

Exclusion Criteria:

• For the second study patients with other alopecias, patients denying data sharing despite signing the informed concent and presenting outside the study period are excluded.
• For the third study, patients with other types of alopecia, as well as those who signed the informed consent but refused to share their data or undergo blood tests at our hospital, and those who did not visit our outpatient department at least once a month for the required duration, were excluded.

Adult and children patients with a dermatologic condition between 1/1/2011-31/12/2020 and for the second study, adults and children with first-onset/relapsing/persistent-untreated alopecia areata visiting our clinic between 15/10/2021 and 14/10/2022 who sign informed consent are eligible.