But were those truly associated with the novel coronavirus? After all, many other factors could be at play.
“Many viral infections can trigger a skin rash, so when you catalog these case reports, you have to have other data. Was the patient on a medication a week before the rash began? Are there other possible causes?” asked Dr. Art Papier, an associate professor of dermatology at the University of Rochester Medical Center in New York.
“This is the challenge that Covid-19 brings up. With these different types of presentations and different rashes, is it hives because the patient just has hives or hives related to Covid-19?”
The researchers — from NewYork-Presbyterian/Weill Cornell Medical College — wrote in their report that the skin discoloration could represent partial occlusion or blockage of blood vessels, and the retiform purpura could represent full blockage.
Such rashes and discoloration of the skin can be a “clinical clue” to there being possible blood clotting in the body, the study said.
The report comes with some limitations, including that the researchers were not able to confirm the precise timing of when rashes and other issues with the skin first appeared for each patient. Also, more research is needed to determine whether similar findings would emerge among a larger group of Covid-19 patients.
Yet overall, the researchers wrote in their report that physicians caring for Covid-19 patients should be aware of skin discoloration and rashes as “potential manifestations” of abnormal underlying blood clotting.
‘Many viral infections can affect the skin’
Doctors and researchers from around the world also have reported about other types of skin rashes among Covid-19 patients.
Covid-19 often triggers significant inflammation in its victims, in some cases producing the so-called cytokine storm that appears to be causing the worst damage in advanced patients.
The skin is particularly sensitive to inflammation, said board certified dermatologist Dr. Seemal Desai, a spokesperson for the American Academy of Dermatology.
“The cytokines that are cranking up the immune engine of the car is what then triggers a variety of these immune molecules to go into the skin and wreak havoc on the skin,” said Desai, a dermatologist in Plano, Texas.
The KLC team then set up a separate online survey, gathering information from nearly 12,000 people with skin rashes and suspected or confirmed Covid-19. The researchers found that 17% of respondents who tested positive for the coronavirus reported a rash as the first symptom of the disease. For 21% of people who reported a rash and had confirmed Covid-19, the rash was their only symptom.
“However, it is important that people know that in some cases, a rash may be the first or only symptom of the disease,” Bataille said. “So if you notice a new rash, you should take it seriously by self-isolating and getting tested as soon as possible.”
Measles-like rashes and rashes inside the mouth
“It’s a reaction that we typically call morbilliform which means measles, which presents in kind of pink spots, lots of little pink spots all over the skin,” said Papier, the dermatologist at the University of Rochester Medical Center.
The mean amount of time between the onset of Covid-19 symptoms and developing enanthem was about 12 days among the patients, according to researchers from the Hospital Universitario Ramon y Cajal in Madrid.
“This work describes preliminary observations and is limited by the small number of cases and the absence of a control group,” the researchers wrote, adding that their findings still suggest enanthem to be a possible Covid-19 symptom and not a reaction to medications, for instance.
“Despite the increasing reports of skin rashes in patients with COVID-19, establishing an etiological diagnosis is challenging,” the researchers wrote. “However, the presence of enanthem is a strong clue that suggests a viral etiology rather than a drug reaction.”