The So-Called 'Corona Toes' Were Unrelated to COVID-19 [Reading Science]

[Asia Economy Reporter Kim Bong-su] It was shortly after the COVID-19 pandemic began in 2020. Among those infected with COVID-19, some exhibited symptoms where their toes appeared discolored, swollen, and inflamed, resembling frostbite, a phenomenon known as 'COVID toes,' which shocked the world. However, a study has now revealed that these symptoms are actually 'chilblains' unrelated to COVID-19. According to the international journal Nature on the 17th, a research team from Yale University conducted detailed examinations and studies on 21 patients in Connecticut who reported such symptoms in early 2020. Among them, 19 showed no evidence of COVID-19 infection. Only 2 patients showed signs of COVID-19 infection, and one of these had already been confirmed positive earlier. This paper was published in the Proceedings of the National Academy of Sciences (PNAS) on the 25th of last month.

In this study, most patients developed 'COVID toes' symptoms between April and May 2020, when COVID-19 cases surged in Connecticut. One-third reported experiencing COVID-19 symptoms before the onset of toe pain, swelling, and discoloration, and another one-third had contact with confirmed or suspected COVID-19 cases. The research team attempted to detect traces of COVID-19 infection in these patients through various methods, including antibody and T-cell detection related to autoimmunity, but failed.

A patient's foot showing symptoms of 'COVID toes' such as swelling like frostbite, inflammation, and discoloration. Photo by Nature

The research team concluded that the COVID toes symptoms were caused by reasons unrelated to the COVID-19 virus. Professor Jeff Gelhausen of Yale School of Medicine pointed out, "These symptoms may have occurred because people stayed at home without wearing shoes or socks due to quarantine measures."

On the other hand, some dissenting opinions suggest further research is needed. In children, it is possible that they fought off the virus using innate immunity without producing antibodies after exposure to COVID-19. The Yale research team noted that antibody tests alone could not determine COVID-19 infection status in the children studied.

Esther Freeman, Director of Global Health Dermatology at Massachusetts General Hospital, who did not participate in this study, told Nature, "These results raise several very interesting questions worthy of further research," adding, "For example, this study does not exclude the possibility that people exposed to the virus fought it off using innate immune responses that do not stimulate the body to produce detectable antibodies and T-cells."

Meanwhile, there was also a completely opposite research result. In October last year, a UK research team published a paper comparing 50 patients with this condition and those with chilblains, suggesting that it could be a side effect of the immune system's response to fight the COVID-19 virus. They claimed it was a phenomenon where the body attacks its own cells and tissues during the process of eliminating the virus.