Could ‘COVID Toes’ Be An Autoimmune Response?
October 7, 2021
Doctors from the Saint-Louis Hospital in Paris published a study this week in the British Journal of Dermatology, examining a skin condition called chilblain-like lesions (CLL) that some are developing alongside their COVID-19 infection. Chilblains is a skin condition thought to be triggered by cold that causes redness, swelling, blisters, or red/purple bumps on toes and sometimes fingers. This outbreak of CLL during the pandemic has been reported extensively and has since been called ‘COVID toes.’
The link between a SARS-CoV-2 infection and CLL has not been well established; the doctors in this study compared 50 patients with COVID toes against 13 patients who had experienced chilblains prior to the start of the pandemic. They found that patients in both groups had high amounts of a protein called type 1 interferon (IFN) and an antibody called anti-neutrophil cytoplasmic antibodies (ANCA). This finding led the researchers to believe that the COVID toes may be caused by an autoimmune response to the virus.
IFN is released during an immune response to infection and has been found to mediate diseases such as systemic lupus erythematosus. ANCA has also been linked to autoimmune diseases such as granulomatosis with polyangiitis (formerly known as Wegener granulomatosis), eosinophilic granulomatosis with polyangiitis (previously known as Churg-Strauss syndrome), and microscopic polyangiitis.
It is still unknown whether people living with these autoimmune diseases are more prone to developing COVID toes with a SARS-CoV-2 infection, or whether COVID toes may lead to the development of autoimmune diseases with the same antibodies.