LAUSR

Several COVID-19 vaccines have been developed to date in an effort to slow the spread of SARS-CoV-2 infections and to reduce disease-related morbidity and mortality. These COVID-19 vaccines have the potential to induce immunemediated adverse side effects, particularly in young women diagnosed with pre-existing autoinflammatory or autoimmune conditions [1]. Here, we report a 20-year-old woman who developed alopecia areata (AA) two weeks following a booster shot of the Sinovac COVID-19 vaccine, which is an inactivated SARS-CoV-2-specific vaccine produced in China. In April 2022, a 20-year-old woman presented to our outpatient clinic with multiple hairless patches throughout her scalp. She did not report any personal or family history of AA or other autoimmune diseases, and indicated that this progressive hair loss had occurred rapidly over the two-week interval since she received a Sinovac COVID19 vaccine booster shot. She had not experienced any apparent hair loss after receiving either of the two previous doses of this vaccine, nor did she report a history of symptomatic COVID-19 infection. Two days prior to her most recent booster shot, a COVID-19 naso-oropharyngeal swab test proved negative. Physical examination revealed multiple patches of alopecia on the scalp without any evidence of scarring or inflammatory erythema. The Severity of Alopecia Tool (SALT) score was 30 (figure 1A-C). No other cutaneous or systemic abnormalities were found upon general examination. The pull test was diffusely positive. Dermoscopy (FotoFinder bodystudio ATBM) examination revealed broken hairs, black dots, and some exclamationmark hairs, consistent with active AA (figure 1D). No evidence of fungal infection was observed, and all laboratory tests, including those for thyroid function, anti-thyroid antibodies, antinuclear antibodies, and IgE levels, were within normal limits. The patient was prescribed a combination of topical and oral steroids, and is currently undergoing clinical follow-up. AA is an autoimmune disease that arises in genetically susceptible individuals and is characterized by non-scaring hair loss. While the specific causes of AA remain poorly understood, hair bulb inflammation and the disruption of the normally immune-privileged status of hair follicles are thought to contribute [2]. Several environmental triggers have been proposed, including dietary factors, hormonal changes, psychological stress, viral infection, and even vaccines [3]. To the best of our knowledge, only a few cases of AA occurring following COVID-19 vaccination have been reported in the literature [3-8]. We describe here the first known case of AA triggered by a booster shot of the inactivated Sinovac COVID-19 vaccine developed in China, although we cannot exclude the possibility that this patient had previously unnoticed AA following her initial two doses of this vaccine. The adverse immune-related side effects associated with COVID-19 vaccination may be governed by several different processes, including molecular mimicry-mediated production of pathological autoantibodies [9]. The adjuA