Abstract
BACKGROUND: Alopecia areata (AA) is characterized by an autoimmune inflammatory response to hair follicles. Several studies have suggested that infection and vaccination can trigger an autoimmune process around hair follicles. Moreover, reports of AA and various other autoimmune diseases have increased since the coronavirus disease 2019 (COVID-19) pandemic became established. OBJECTIVE: We assessed the clinical characteristics and treatment response in patients who developed AA following COVID-19 infection or vaccination. METHODS: This retrospective study involved patients who had developed COVID-19 or received a COVID-19 vaccination within 3 months before the onset or aggravation of AA from January 2020 to December 2022. RESULTS: Fifty patients met the inclusion criteria. Eighteen patients had a history of COVID-19 infection, and 32 had a history of COVID-19 vaccination. The mean onset of AA after COVID-19 infection and vaccination was 5.22±3.35 and 4.13±2.73 weeks, respectively. The most common COVID-19-associated symptoms before AA were fever (88.9%) in the infection group and myalgia (50.0%) in the vaccination group. In the vaccination group, AA most commonly occurred after receiving the Pfizer-BioNTech vaccine (BNT162b2, 46.9%) or Moderna vaccine (mRNA-1273, 34.4%). The vaccination group showed more rapid improvement than the infection group; however, both showed significant improvement after 6 months of treatment of AA. CONCLUSION: We examined the clinical characteristics and treatment responses of patients who developed AA after COVID-19 infection or vaccination. Further research is needed to evaluate the detailed pathogenesis and association between COVID-19 and AA.