Understanding Alopecia Areata: An Estimation of the Portuguese Epidemiology Data

OBJECTIVES: To assess the clinical and demographic characteristics of Alopecia Areata (AA) patients and estimate the number of AA patients per disease type and extent in Portugal.

METHODS: An observational, cross-sectional study, using a qualitative survey of dermatologists in Portugal with experience in AA management. The AA extent was defined by SALT score by quantifying the percentage of scalp hair loss: mild (≤20); moderate (21-49); severe (≥ 50) which was classified according to dermatologists’ discretion. The survey conducted from 2023-08-07 to 2023-11-15, comprised 22 close-ended, multiple choice, multi-select, and Likert scale measurement response questions. The number of patients by disease type and extent was estimated with a 95% CI extrapolating the study sample (N=178) and the AA prevalence data from the 2019 Global Burden of Disease study.

RESULTS: A total of 13 dermatologists answered the survey. The total monthly number of patients was 178 with 51 new AA diagnoses. Most of these patients were women (57%) aged between 18-40 years old. The results showed that patchy AA is the most common clinical pattern, affecting 69% of patients followed by universalis, ophiasis and totalis (9%, 9% and 8%, respectively). Severe AA is more common in adults than in adolescents and children (27%,13% and 6% respectively). It was estimated that AA affects 31,004 patients. Patchy AA affects ~21,000 patients, universalis and ophiasis affects almost 3,000 patients each, ~2,500 have totalis, <1,000 are affected by diffuse, and ~600 have sisaipho AA. Around 500 children (0 to 11 years), ~500 adolescents (12 to 17 years), and almost 18,000 adults were estimated to have moderate to severe AA.

CONCLUSIONS: Seventy-three % of AA patients were adults. It is estimated that ~19,000 patients (all age groups) have moderate to severe disease. Further studies are needed to confirm these epidemiological findings.