Autoimmune Skin Diseases in the Era of COVID-19: Pathophysiological Insights and Clinical Implications

The COVID-19 pandemic has highlighted intricate associations between SARS-CoV-2 infection and autoimmune skin diseases (ASDs). This review examines the bidirectional relationship between COVID-19 and ASDs including hidradenitis suppurativa, psoriasis, atopic dermatitis, alopecia areata, autoimmune bullous diseases, cutaneous and systemic lupus erythematosus, systemic sclerosis, dermatomyositis, and lichen planus. Current evidence indicates that SARS-CoV-2 may precipitate or worsen ASDs via mechanisms such as molecular mimicry, dysregulated cytokine signaling, and enhanced Th1/Th17 immune responses, leading to loss of self-tolerance and autoantibody production. Epidemiological studies have identified increased incidence and flares of psoriasis, hidradenitis suppurativa, and other ASDs following both COVID-19 infection and vaccination, with mRNA vaccines associated with a higher risk of flare in hidradenitis suppurativa compared with non-mRNA vaccines. Notably, severe COVID-19 is associated with a greater risk of new-onset autoimmune disease, and patients with pre-existing inflammatory skin conditions may have increased susceptibility to SARS-CoV-2 infection but experience less severe COVID-19 courses. These findings underscore the need for ongoing surveillance and mechanistic studies to clarify the immunopathogenic links between SARS-CoV-2 and ASDs and inform management strategies for affected patients in the context of both infection and vaccination.