Doctors around the world are reporting that some patients diagnosed with COVID-19 develop skin rashes, including a frostbite-like rash on the feet dubbed “Covid toes.”
These reports are observational, so it’s unclear if the rashes are symptoms of COVID-19 or something else, such as a reaction to medications used to treat the infection. Neither the U.S. Centers for Disease Control and Prevention nor the World Health Organization currently lists skin rash as a symptom of COVID-19.
How common the rashes are is also unclear. A Chinese study published in February reported that skin rashes were present in only 0.2 percent of more than 1,000 COVID-19 patients, while a smaller Italian study published a month later put the prevalence at 20.4 percent.
It’s certainly not unheard of for viruses to trigger skin rashes, however. Measles, chickenpox and herpes are examples of viral infections with distinctive rashes — the result of the inflammation caused when the immune system fights the infection within the skin’s cells. COVID-19 could generate a similar skin reaction in some patients.
Five types of rashes
In a peer-reviewed paper published last week in the British Journal of Dermatology, a group of Spanish researchers described five different categories of rashes among COVID-19 patients. They came up with those categories after asking dermatologists in Spain to report details of any rashes they had observed in their COVID-19 patients within the previous two weeks. The dermatologists submitted 375 case examples.
Here are the five types of rashes they identified from those cases:
- A rash on the hands or feet that resembles chilblains (the so-called Covid toes). These rashes, which occurred in 19 percent of the Spanish cases, were often itchy and/or painful. They primarily affected younger COVID-19 patients and were associated with mild infections. The rash tended to appear later in the illness and lasted an average of 12 days.
- A blistery rash. Consisting of tiny, similarly shaped blisters, this rash was found on the abdomen or back of some patients and on the arms or legs of others. It primarily affected middle-aged patients and tended to appear earlier than other symptoms of COVID-19. Often itchy, the rash lasted for an average of about 10 days. It was found in 9 percent of the cases.
- A hives-like rash. This itchy rash consisted of small, slightly elevated reddish or white patches on the skin. Most patients developed the rash on their bodies, but in a few cases it appeared on the patients’ palms. The rash lasted for an average of about 7 days and was associated with more severe cases of COVID-19. It was found in 19 percent of the cases.
- A maculopapular rash. It consisted of small reddish bumps on a flat, reddish patch of skin. The sometimes-itchy rash tended to appear at the same time as other symptoms of COVID-19 and was associated with more severe cases of the illness. It lasted for an average of about nine days. This was the most common rash reported in the study, appearing in 47 percent of the cases.
- Livedo (also known as necrosis). A sign of poor blood circulation, this rash was characterized by purplish skin with a lace-like pattern. It was found in older patients with more severe illness. Six percent of the COVID-19 patients in the study had this skin condition.
In case studies published in the April 30 issue of JAMA Dermatology, doctors identified two additional types of skin conditions that may be associated with COVID-19: petechiae (tiny purple, red or brown spots caused by bleeding under the skin) and a scaly rash called digitate papulosquamous.
More questions than answers
Again, it’s too early to know if Covid toes or any other rash is actually caused by the coronavirus.
“Early reports about the cutaneous [skin] eruptions seen in patients with COVID-19 raise more questions that they provide answers,” write three American dermatologists, including Dr. Kanade Shinkai, editor-in-chief of JAMA Dermatology, in an editorial that accompanied the case studies.
“The significance of a cutaneous eruption associated with COVID-19 remains unclear, especially as it pertains to prognosis,” they add. “It will require additional study to determine if specific host or pathogen factors contribute to the likelihood of developing a rash, and especially a specific pattern of rash.”
The organization hopes the database will help doctors and scientists “understand the relationship between the virus and skin” and then possibly use that information to help with early detection of the illness.
FMI: You can read the Spanish paper on the different types of rashes at the British Journal of Dermatology’s website.