Characteristics of hair loss in COVID-19 patients in Thailand.

There is still a scarcity of data on hair loss caused by coronavirus disease 2019 (COVID-19) infection. This study aims to determine the characteristics of hair loss in Thai individuals after COVID-19 infection and to identify associated factors. From March to June 2022, a retrospective review of medical records and telephone interviews was conducted to determine the details of hair loss, the severity of infection, and the associated treatments of patients with an abrupt onset of hair loss after the diagnosis of COVID-19 infection at Siriraj Hospital in Bangkok, Thailand. This study included 43 patients who experienced hair loss within 4 months after COVID-19 infection. The mean age was 46.5 ± 14.5 years, predominantly women. Most had mild COVID-19 symptoms (59.3%), and 59.1% experienced weight loss, with a mean weight loss of 4.3 ± 2.0 kg per month. Preexisting hair loss was reported in 31.0% of participants, with approximately 3-quarters diagnosed with androgenetic alopecia. The median onset of hair loss after COVID-19 infection was 30 days (interquartile range 30-60). Telogen effluvium was the most common acute hair loss diagnosis, and topical minoxidil was the predominant treatment (95.3%). Female gender was correlated with a more severe shedding scale (adjusted odd ratio 24.76, 95% CI 1.67-168.86). Patients with a history of androgenetic alopecia tended to have a lower hair shedding scale (adjusted odd ratio 0.03, 95% CI 0.01-0.38). This study reviewed the characteristics of hair loss after COVID-19 infection during Omicron outbreaks in Thailand. The COVID-19-associated telogen effluvium, which is the primary cause in our patients, manifested with earlier onset at approximately 30 days.