Doctors find more cases of 'COVID toes' in dermatological registry. Here's what they learned

Doctors are learning more about COVID-19’s newest and oddest skin manifestation, dubbed COVID toes, as the Centers for Disease Control and Prevention adds to the growing list of symptoms
associated with the coronavirus.

The American Academy of Dermatology has compiled a registry of skin manifestations associated with COVID-19. About half of the more than 300 total cases on the dermatological registry consist of COVID toes.

The registry is made up of entries by physicians and other health care professionals who fill out a 5-7 minutes survey about patients with confirmed or suspected COVID-19 who develop skin manifestations, as well as patients with existing dermatological conditions who develop COVID-19 and patients on dermatological medications who developed COVID-19. Entries can not be made by patients themselves.

Dr. Esther Freeman, director of Massachusetts General Hospital Global Health Dermatology and member of the AAD task force on COVID-19, said COVID toes are pinkish-reddish “pernio-like lesions” that can turn purple over time.

She said this shouldn't be confused with a different medical condition that occurs in critically sick patients called purpura fulminans.

When she first started the registry with the academy, she was expecting to see viral rashes often driven by inflammation.

“What was more surprising to me was this overwhelming representation of these ‘COVID toes,’” she said.

Pernio, also called chilblains, are skin sores or bumps that occur on a patient’s feet when they’re exposed to cold temperatures. The reason why Freeman calls the new symptom “pernio-like” is because she believes COVID toe lesions aren’t a result of cold temperatures.

While experts can’t confirm why COVID toes appear, they have some educated guesses. One could be inflammation in the toes' tissue, which is similar to pernio. Another hypothesis is inflammation of the blood vessel wall, medically known as vasculitis. And finally, Freeman said it is possible COVID toes could be caused by small blood clots that form inside the blood vessel.

Doctors at the American Academy of Dermatology have discovered trends studying the registry that weren’t previously known about COVID toes. Freeman says COVID toes have appeared in some cases of asymptomatic patients. The majority of the toe cases manifested simultaneously or after more common COVID-19 symptoms, rather than before.