DALLAS (NEXSTAR) — A Harvard researcher believes skin rashes could be a new symptom of COVID-19.

Andrew Chan, a professor of immunology and infectious disease at the Harvard T.H. Chan School of Public Health, has been tracking coronavirus patients using the COVID Symptom Study app. He says the app is picking up more cases of raised skin bumps and inflammation on fingers and toes.

The rashes were placed into three categories:

  • Hive-type rash (urticaria): Sudden appearance of raised bumps on the skin that come and go quickly over hours and are usually very itchy. It can involve any part of the body and often starts with intense itching of the palms or soles and can cause swelling of the lips and eyelids. These rashes can present quite early in the infection, but can also last a long time afterward.
  • ‘Prickly heat’ or chickenpox-type rash (erythemato-papular or erythemato-vesicular rash): Areas of small, itchy red bumps that can occur anywhere on the body, but particularly the elbows and knees as well as the back of the hands and feet. The rash can persist for days or weeks.
  • COVID fingers and toes (chilblains): Reddish and purplish bumps on the fingers or toes, which may be sore but not usually itchy. This type of rash, most specific to COVID-19, is more common in younger people with the disease and tends to present later.

Chan’s research focused on rashes involved roughly 336,000 app users in the United Kingdom.

Similarly, an early study on COVID found 17 percent of the 11,546 people surveyed had a rash as their first COVID-19 symptom. Of those who reported suffering from a rash, 21 percent said it was their only symptom.

“Even though skin rashes may not be that common in COVID, the fact that they do arise, the fact that they may be a more specific sign, highlight how important it is to really assess their prevalence and how predictive they are,” Chan said in an interview with VOX.

As of now, rashes aren’t listed as a coronavirus symptom by the Centers for Disease Control and Prevention. The CDC-approved symptoms are:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

The CDC notes the above list does not include all symptoms and symptoms may appear 2-14 days after exposure to the virus.