Commentary: Genetic studies suggest that inflammatory skin diseases increase the risk of COVID-19

Genetic studies suggest that inflammatory skin diseases increase the risk of COVID-19.

An article recently published in the Journal of Allergy and Clinical Immunology¹ suggests that diseases such as psoriasis and atopic dermatitis increase the risk of COVID-19 by approximately 50%. The authors of the study (Lam Tsoi and collaborators, University of Michigan) examined the medical records of 435,000 individuals, 1115 of whom had been diagnosed with COVID-19. After adjusting their analysis for the age, ethnicity, body mass index, and socioeconomic status of participants, they found that having an inflammatory skin disorder (acne, atopic dermatitis, or psoriasis) conferred an increased risk of COVID-19 while reducing the likelihood of requiring mechanical ventilation.

The authors next analyzed publicly available expression data and observed a significant overlap between the genes that are up-regulated in inflammatory skin diseases and those that are induced by SARS-CoV2 infection in bronchial epithelial cells. Of note, the shared genes were mostly involved in epidermal barrier function and innate antiviral responses.

In the final stage of the study, the authors re-examined published genome-wide association studies and found a marker that was associated with susceptibility to both psoriasis and COVID-19. Interestingly, the variant maps in proximity to S100A12, a gene that is up-regulated in psoriatic lesions and in SARS-CoV2 infected cells.

These observations suggest a link between skin inflammation and COVID-19 susceptibility. The authors speculate that in individuals with psoriasis or atopic dermatitis, SARS-CoV2 could enter the organism through the skin, exploiting defects in epidermal barrier function. Progression to severe disease would then be hindered by the activation of immune responses at sites of inflammation. While these hypotheses could be tested in animal models, the authors acknowledge that the underlying observations will need to be replicated in further genetic and epidemiological studies.