Fact check: Are foot sores a new symptom of COVID-19? It's too soon to say

The claim: Chicken-pox-like sores, particularly on the feet of young COVID-19 patients, are a new coronavirus symptom 

When "Inside Edition" reported a new foot-sore symptom of COVID-19 on April 16, the claim was quickly met with skepticism.

Many Facebook users questioned the claim in the comment section: "So let me get this straight anything is a symptom now?", "Hair falling out, tongue swelling..let's add a few more" and "Looks like a bruise to me .. he stubbed his toe."

"Doctors in Europe (reported) they are seeing foot sores on a number of patients, similar to chicken pox," Inside Edition's Steven Fabian reported.

The small blue patches are showing up, in particular, on kids' feet and appear to be more common than once believed, Dr. Mehmet Oz of "The Dr. Oz Show" told "Inside Edition."

"Doctors initially thought they were spider bites or some unrelated condition, but it turns out they're probably from blood vessels blocked-off from the virus," Oz said. "And if you see them, that's one of the signs that you may actually have COVID-19."

Several news outlets, including The Daily Mail, partnering newspaper Metro, New York Post, the "Today Show" and USA TODAY have since reported this new possible symptom that dermatologists have now dubbed "COVID toes." Some doctors agree these foot sores are likely a symptom of COVID-19, however, the cause is still up for debate.

What are 'covid toes'?

"They’re typically painful to touch and could have a hot burning sensation,” said Dr. Ebbing Lautenbach, the University of Pennsylvania Oerelman School of Medicine's chief of infectious disease.

The symptom is unique because it tends to appear in asymptomatic patients, as with the sudden loss of smell or taste.

“This is a manifestation that occurs early on in the disease, meaning you have this first, then you progress,” Lautenbach said. “Sometimes this might be your first clue that they have COVID when they don’t have any other symptoms.”

The sores have presented in patients in Spain, Italy, France, Thailand and now the United States. The condition, documented in the Journal of the American Academy of Dermatology, has been described as a rash resembling Dengue, another infectious disease, or a type of Transient Livedo Reticularis, a temporary skin condition with a blotchy, netlike pattern.

In an April 9 statement, The Spanish General Council of Official Podiatrist Colleges wrote that the sores are "increasingly being detected in patients with COVID-19, especially children and adolescents," though they can also appear on adults.

The council also announced that its plan to create a registry to monitor COVID-19 cases involving these lesions.

COVID-19 can cause other skin symptoms

The American Academy of Dermatology has created a COVID-19 registry to track incidents of COVID-19 cases involving skin conditions and preexisting conditions. About 130 cases have been submitted to the registry, so far, according AAD President Dr. Bruce H. Thiers.

"The skin is the body’s largest organ and, in some cases, changes in the skin – often in the form of a rash – can be a sign of an underlying health condition," Thiers told USA TODAY. 

The AAD's and the Spanish General Council of Podiatrists Colleges' registries are part of the medical community's ongoing effort to understand COVID-19 and its symptoms.

The Hospitalist, the Society of Hospital Medicine's official news magazine, interviewed Dr. Randy Jacobs, an assistant clinical professor of dermatology at University of California, Riverside.

He described a 67-year-old COVID-19 patient whose first symptoms resembled the common cold. A week later, the patient developed a rash on his inner-thigh and began urinating blood. Though both conditions went away within 24 hours, the patient later tested positive.

The rash, called a transient livedo reticularis, was blocking the blood vessels in the patient's kidney, causing him to urinate blood, Jacobs told USA TODAY.

"With 'COVID,' you see this rash and some of the patients notice it comes and goes," he said.  

Jacobs told Health.com that the rash is usually autoimmune related and that he observed it in three of his patients who were diagnosed with COVID-19. 

Health.com reported that a small, observational study of 88 patients in Italy showed that about 20% developed some sort of skin condition that may be related to COVID-19. The findings were documented in the Journal of the European Academy of Dermatology and Venereology.

Jacobs' findings will be published in the Journal of the American Academy of Dermatology, Health.com reports.

Medical experts disagree on the cause

The World Health Organization and the Centers for Disease Control have yet to recognize these foot sores as a symptom of COVID-19. Both organizations continue to warn the public of symptoms including fever, dry cough, difficulty breathing or shortness of breath, chills, muscle aches, headache, sore throat, or loss of taste and smell.

The Spanish General Council of Official Podiatrist Colleges addressed the lack of evidence surrounding the cause of these sores in its April 9 statement.

"Obviously, due to the short time elapsed, scientific evidence cannot be discussed yet," the council said, stressing the importance of the symptom despite the lack of research. "The Council of Podiatrists urges its Colleges and its members to be very vigilant because this may be a sign of COVID-19 detection that can help to avoid the spread."

Lautenbach suggested the sores could be caused by the body's response to the coronavirus in the form of localized foot inflammation and clotted blood vessels.

"The short answer is, nobody knows," Lautenbach said.

Jacobs told USA TODAY that he suspects the sores may be attributable to something other than the coronavirus, though a biopsy would be needed to determine the cause.

"Chilblains — where the toes turn dark due to lack of blood supply, can happen," he offered as a possible cause of the sores. "Shingles can be activated by any kind of illness. You can break out with what looks like chicken pox." 

Jacobs, Ebbing and Oz all agree that the presence of these sores indicates "a pretty good chance"  that a patient may be diagnosed with COVID-19. 

Our rating: More information needed

The claim that foot sores may be an early symptom of COVID-19, particularly for young patients, cannot be rated as true or false at this time because more research is needed. Multiple reports — as well as a published study — relay that COVID-19 patients are developing sores and lesions. It is possible the foot sores are caused by the coronavirus, but there is not yet enough evidence. Sores also could be attributed to a preexisting condition or coincidental. Regardless, doctors agree that the medical community should be aware of foot sores as a possible symptom when working to minimize the spread of COVID-19.

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