Under-representation of people of African ancestry in publications on the cutaneous manifestations of COVID-19: coincidence or physiology?

Conflicts of Interest

C. Cassius state no conflict of interest; L Frumholtz state no conflict of interest; A de Masson state no conflict: O Dadzie state no conflict of interest; A. PETIT state no conflict of interest.

To the Editor,

Recent publications have highlighted the rarity of patients with dark skin among COVID‐19‐related skin eruptions. Indeed, very few patients of non‐European descent were reported among 318 cases of COVID‐19‐related perniosis and there was a virtual absence of ‘Covid toes’ among a large population of African‐American and Hispanic patients during the COVID‐19 outbreak in New York City.

These results prompted us to review the clinical charts and photographs of 80 patients referred by general practitioner, private practice dermatologists or emergency services to our department for chilblain‐like lesions during the first wave of COVID‐19 outbreak in Paris, between 9 April and 16 April 2020. None of the patients were of sub‐Saharan African descent or had Fitzpatrick’s skin phototype of 5 or 6. These findings contrast with the usual visits to our institution – 30% of our outpatient population are of sub‐Saharan African descent, with phototype 5 or 6.

Two recruitment biases may be cited as reasons for the ‘ethnic’ differences in relation to COVID‐19‐chilblain‐like lesions, but none of them seems plausible. Poor visibility of erythema and inadequate training in recognizing skin manifestations in richly pigmented skin is unlikely to be pertinent in this setting, given that chilblain‐like lesions are usually symptomatic and hence unlikely to be missed/neglected by either patients or doctors. Socio‐economic factors precluding access to dermatological care cannot explain the virtual absence of chilblain‐like lesions in African‐American and Hispanic patients in New York. Finally, data from all the published studies support ethnic differences in relation to the incidence of COVID‐19‐related chilblain‐like lesions. Vascular skin reactions of poor prognosis, such as ecchymosis or necrosis, were not reported in the study by Lester et al. nor in a short case series of COVID toes in people of Fitzpatrick skin types III to V.

In most of the published series, chilblains appeared to affect young patients with discrete to mild symptoms of COVID‐19 and no microbiological or serological evidence of SARS‐CoV‐2 infection. This has led Hebert et al. to refute any link between SARS‐CoV‐2 infection and such lesions. According to these authors, several biases could contribute to the concomitance of COVID‐19 and chilblains outbreaks; however, such biases could hardly account for the aforementioned differences between patients of diverse ethnic backgrounds.

It is noteworthy that patients of African descent not only show fewer, if any, chilblain‐like lesions, but also have a poorer prognosis when infected by the SARS‐CoV‐2. This could suggest a pathophysiological link between a more effective immune response to SARS‐CoV‐2 infection and the development of acral vascular lesions. According to this hypothesis, the restriction of chilblain outbreaks primarily to people of European ancestry may be due to genetic factors (e.g. those impacting immune response) that predispose to the development of both chilblains and milder forms of COVID‐19.

Funding sources

None.