A response to “Male balding is a major risk factor for severe COVID-19”
Authors: Akshitha Thatiparthi, Jeffrey Liu, Amylee Martin, Jashin J. Wu
Journal: Journal of the American Academy of Dermatology (2020)

To the Editor: We read with great interest Male Balding is a Major Risk Factor for Severe COVID-19 by Lee et al1Lee J. Yousaf A. Fang W. Kolodney M. Male balding is a major risk factor for severe COVID-19.J Am Acad Dermatol. 2020; 83: e353-e354Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar regarding androgenic alopecia as a risk factor for COVID-19 severe symptomatology. A recent study by Wambier et al2Wambier C.G. Vaño-Galván S. McCoy J. et al.Androgenetic alopecia present in the majority of hospitalized COVID-19 patients - the "Gabrin sign.".J Am Acad Dermatol. 2020; 83: 680-682Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar observed similar findings regarding androgenic alopecia and COVID-19. Yet, the relationship between scalp health, androgenic alopecia, and COVID-19 has not been explored. We examined the current, yet limited, literature regarding the role of the scalp in preventing transmission of COVID-19. Trüeb et al3Trüeb R.M. Henry J.P. Davis M.G. Schwartz J.R. Scalp condition impacts hair growth and retention via oxidative stress.Int J Trichology. 2018; 10: 262-270Crossref PubMed Scopus (38) Google Scholar describes the importance of scalp and hair health. The scalp has a large number of terminal hairs and microbes creating a unique microenvironment. Hair is a mechanical barrier, blocking ultraviolet radiation from reaching the scalp skin and facilitates moisture retention.3Trüeb R.M. Henry J.P. Davis M.G. Schwartz J.R. Scalp condition impacts hair growth and retention via oxidative stress.Int J Trichology. 2018; 10: 262-270Crossref PubMed Scopus (38) Google Scholar Aging and male sex hormones can compromise hair growth, resulting in androgenic alopecia. Alteration of hair production and pre-existing photo-aging results in scalp atrophy and increased exposure to ultraviolet radiation.3Trüeb R.M. Henry J.P. Davis M.G. Schwartz J.R. Scalp condition impacts hair growth and retention via oxidative stress.Int J Trichology. 2018; 10: 262-270Crossref PubMed Scopus (38) Google Scholar These effects change scalp volume, alter cellularity of the epidermis, and elevate dermal inflammatory cells.3Trüeb R.M. Henry J.P. Davis M.G. Schwartz J.R. Scalp condition impacts hair growth and retention via oxidative stress.Int J Trichology. 2018; 10: 262-270Crossref PubMed Scopus (38) Google Scholar Premature balding increases risk of scalp damage, as there is a loss of elasticity and moisturized protective barrier. Furthermore, scalp balding increases the expression of oxidative stress markers resulting in DNA damage.3Trüeb R.M. Henry J.P. Davis M.G. Schwartz J.R. Scalp condition impacts hair growth and retention via oxidative stress.Int J Trichology. 2018; 10: 262-270Crossref PubMed Scopus (38) Google Scholar The combination of factors sensitizes scalp skin environmental stress and pathogens, including viruses such as COVID-19.1Lee J. Yousaf A. Fang W. Kolodney M. Male balding is a major risk factor for severe COVID-19.J Am Acad Dermatol. 2020; 83: e353-e354Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar, 2Wambier C.G. Vaño-Galván S. McCoy J. et al.Androgenetic alopecia present in the majority of hospitalized COVID-19 patients - the "Gabrin sign.".J Am Acad Dermatol. 2020; 83: 680-682Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar, 3Trüeb R.M. Henry J.P. Davis M.G. Schwartz J.R. Scalp condition impacts hair growth and retention via oxidative stress.Int J Trichology. 2018; 10: 262-270Crossref PubMed Scopus (38) Google Scholar, 4Xue X. Mi Z. Wang Z. Pang Z. Liu H. Zhang F. High Expression of ACE2 on keratinocytes reveals skin as a potential target for SARS-CoV-2.J Invest Dermatol. 2021; 141: 206-209.e1Abstract Full Text Full Text PDF PubMed Scopus (72) Google Scholar COVID-19 is spread via mucosal and skin barriers. ACE2 was recently identified as a vital receptor for cell entry of SARS-CoV-2.4Xue X. Mi Z. Wang Z. Pang Z. Liu H. Zhang F. High Expression of ACE2 on keratinocytes reveals skin as a potential target for SARS-CoV-2.J Invest Dermatol. 2021; 141: 206-209.e1Abstract Full Text Full Text PDF PubMed Scopus (72) Google Scholar Cells with high levels of ACE2 expression, such as pulmonary pneumocytes and keratinocytes, are vulnerable to infections.2Wambier C.G. Vaño-Galván S. McCoy J. et al.Androgenetic alopecia present in the majority of hospitalized COVID-19 patients - the "Gabrin sign.".J Am Acad Dermatol. 2020; 83: 680-682Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar,4Xue X. Mi Z. Wang Z. Pang Z. Liu H. Zhang F. High Expression of ACE2 on keratinocytes reveals skin as a potential target for SARS-CoV-2.J Invest Dermatol. 2021; 141: 206-209.e1Abstract Full Text Full Text PDF PubMed Scopus (72) Google Scholar Increased expression of ACE2 in epidermal keratinocyte cells has been indicated as a possible transmission route of SARS-CoV-2, particularly in conditions compromising skin barrier function.4Xue X. Mi Z. Wang Z. Pang Z. Liu H. Zhang F. High Expression of ACE2 on keratinocytes reveals skin as a potential target for SARS-CoV-2.J Invest Dermatol. 2021; 141: 206-209.e1Abstract Full Text Full Text PDF PubMed Scopus (72) Google Scholar ACE2 receptor expression is influenced by male sex hormones.2Wambier C.G. Vaño-Galván S. McCoy J. et al.Androgenetic alopecia present in the majority of hospitalized COVID-19 patients - the "Gabrin sign.".J Am Acad Dermatol. 2020; 83: 680-682Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar Androgenic hormones play a central role in the pathogenesis of androgenic alopecia, which results in loss of an important scalp protective barrier. Scalp health may be preventative against the transmission of COVID-19, as male pattern balding has been implicated in the development of severe symptomology.1Lee J. Yousaf A. Fang W. Kolodney M. Male balding is a major risk factor for severe COVID-19.J Am Acad Dermatol. 2020; 83: e353-e354Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar, 2Wambier C.G. Vaño-Galván S. McCoy J. et al.Androgenetic alopecia present in the majority of hospitalized COVID-19 patients - the "Gabrin sign.".J Am Acad Dermatol. 2020; 83: 680-682Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar, 3Trüeb R.M. Henry J.P. Davis M.G. Schwartz J.R. Scalp condition impacts hair growth and retention via oxidative stress.Int J Trichology. 2018; 10: 262-270Crossref PubMed Scopus (38) Google Scholar Through suppression of male sex hormones, medications preventing androgenic alopecia may alter ACE2 receptor expression. Accordingly, maintenance of scalp health may be essential in preventing transmission by sustaining a robust skin barrier.2Wambier C.G. Vaño-Galván S. McCoy J. et al.Androgenetic alopecia present in the majority of hospitalized COVID-19 patients - the "Gabrin sign.".J Am Acad Dermatol. 2020; 83: 680-682Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar Scalp hair is a potential protective factor against COVID-19 transmission. Studies are needed to evaluate this relationship, as understanding the link will aid in the creation of appropriate public health measures and treatment options. Potential considerations for exploration include the association between COVID-19 and the effects in other etiologies of alopecia including alopecia areata and frontal fibrosing alopecia. Lastly, human culture determines body coverage with clothes; however, the scalp is usually exposed, and, along with the face and acral areas, become the only zones of temperature control. Thus, there may be a link between neurovascular responses to temperature changes from the scalp and disease incidence that peak seasonally in subtropical areas including human coronavirus strains and potentially COVID-19.5Kissler S.M. Tedijanto C. Goldstein E. Grad Y.H. Lipsitch M. Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period.Science. 2020; 368: 860-868Crossref PubMed Scopus (1671) Google Scholar Further research is warranted to study the link between hair coverage and systemic disease. Male balding is a major risk factor for severe COVID-19Journal of the American Academy of DermatologyVol. 83Issue 5PreviewTo the Editor: Recent observations by Wambier et al1 suggest that men with pattern baldness are at high risk for severe symptomatic COVID-19 infection. Two preliminary studies1,2 noted high rates of androgenic alopecia in men hospitalized for severe COVID-19. Both of these uncontrolled observational studies were limited by small sample size. To further evaluate this intriguing observation, we examined severity of hair loss in 1941 hospitalized male patients tested for COVID-19 using data from the UK Biobank. Full-Text PDF Reply to letter to the editor: "A response to 'Male balding is a major risk factor for severe COVID-19'"Journal of the American Academy of DermatologyVol. 84Issue 2PreviewTo the Editor: We appreciate the interest regarding "Male balding is a major risk factor for severe COVID-19"1 by Thatiparthi et al.2 These authors propose a potential causal relationship between COVID-19 and scalp balding. They suggest that balding could possibly allow the virus to transverse the cutaneous barrier through accelerated photo-aging, oxidative stress, loss of elasticity, and reduced moisturization. Although the possibility of COVID-19 percutaneous transmissibility is a novel perspective, further investigation is needed to determine if SARS-CoV-2 infects epidermal keratinocytes and whether SARS-CoV-2 skin inoculation leads to systemic disease. Full-Text PDF