For some patients, COVID toes and rashes can last long after they recover from the coronavirus, a new study finds.
How often skin problems are linked to COVID-19 isn't known, but some patients -- so-called "long haulers" -- get better but don't appear to fully recover. For these patients, skin symptoms persist for 60 days or longer, according to researchers.
COVID toes and skin rashes are signs of inflammation, said Dr. Esther Freeman, principal investigator of the COVID-19 Dermatology Registry, a joint effort of the American Academy of Dermatology and the International League of Dermatologic Societies.
"Some patients are having long-lasting inflammation that's being in some way triggered by the virus," she said. "We don't yet understand really exactly why or how this is happening, but the skin is particularly interesting and important, because it can be a window into what's going on with the rest of the body. Since it's very visual, you can actually, literally see the inflammation that's happening."
Freeman speculates that these skin problems are signs of an immune system response to the virus.
Using dermatology registry data, the researchers looked at nearly 1,000 cases of skin eruptions among people with COVID-19.
"I think it's important to realize this may be a little bit the tip of the iceberg when it comes to skin. It's probably underreported," Freeman said, noting that the registry doesn't capture all COVID-19 cases in which skin conditions occur.
The researchers reported that redness and swelling of the feet and hands (also known as COVID toes) lasted a median of 15 days in patients with suspected coronavirus infection and 10 days in lab-confirmed cases. That means half of cases lasted longer, half for a shorter time.
Among six long-haulers with COVID toes, however, symptoms lasted 60 days, and two patients had symptoms for more than 130 days, according to the report.
Hive-like rashes lasted a median of four days, and so-called morbilliform rashes lasted for a week, the study found. The maximum duration was 28 days.
Papulosquamous eruptions, which are scaly spots on the skin, lasted a median of 20 days, with one case lasting 70 days, the findings showed.
Dr. Michele Green is a dermatologist at Lenox Hill Hospital in New York City. She said, "These extended skin manifestations are a result of the body's intense inflammatory reaction to COVID-19."
The skin is the body's largest organ and has a crucial role in regulating body temperature, sensation and immune defense, she pointed out.
"It is not surprising to me that such a toxic virus, which unleashes so many cytokines in the body, has a profound reaction and expression on the skin," Green added.
Besides the visible signs on skin, COVID toes can also be painful, according to Freeman. Usually, the discoloration lasts a long while, but the pain and discomfort last about a week.
"Most of my patients that I've taken care of have reported that they're in discomfort from toe swelling and toe pain, usually for about a week, even if the lesions themselves might last for several weeks," Freeman said. "My patients have said it's uncomfortable enough that they can't wear shoes."
For most patients, the condition goes away by itself. But for a small number, it lingers.
"Unfortunately, several of our patients that are in this long-lasting group have experienced prolonged discomfort, so some of our patients have actually been in pain or discomfort in their feet for the entire time that they've had it. These long haulers," Freeman said.
Treatment is a challenge, she added, and no protocol exists. "We're working on that," Freeman said. "I think all of my patients would like the answer to that."
She fears some patients will have long-lasting effects from COVID-19.
"There's certainly a risk that some of our patients may have continued skin issues from COVID-19, and our job is to figure out why this is happening and try to figure out how to treat them," she said.
The study findings were presented Thursday at an online meeting of the Congress of the European Academy of Dermatology and Venereology. Research presented at meetings is typically considered preliminary until published in a peer-reviewed journal.
For more on COVID-19, head to the U.S. Centers for Disease Control and Prevention.
SOURCES: Esther Freeman, MD, PhD, principal investigator, COVID-19 Dermatology Registry, and director, Global Health Dermatology, Massachusetts General Hospital and Harvard Medical School, Boston; Michele Green, MD, dermatologist, Lenox Hill Hospital, New York City; Congress of the European Academy of Dermatology and Venereology, virtual meeting, Oct. 29, 2020