A Response to 'Male Balding Is a Major Risk Factor for Severe COVID-19'

The letter to the editor by Thatiparthi et al. responds to the claim that male balding is a major risk factor for severe COVID-19, suggesting that scalp health may play a role in preventing transmission of the virus. The authors discuss how aging and male sex hormones can lead to androgenic alopecia, which results in scalp atrophy and increased exposure to ultraviolet radiation, potentially sensitizing the scalp to environmental stress and pathogens like COVID-19. They note that the ACE2 receptor, which is important for SARS-CoV-2 cell entry, is expressed in epidermal keratinocytes and that its expression can be influenced by male sex hormones. The authors conclude that scalp hair could be a protective factor against COVID-19 transmission and that further research is needed to understand the relationship between scalp health and COVID-19, as well as the potential impact of other types of alopecia on the virus's transmission and the seasonal incidence of diseases in subtropical areas.