Data from the COVID Symptom Study shows that characteristic skin rashes and ‘COVID fingers and toes’ should be considered as key diagnostic signs of the disease, and can occur in the absence of any other symptoms.
The COVID Symptom Study, led by researchers from King’s College London and health science company ZOE, asks participants to log their health and any new potential symptoms of COVID-19 on a daily basis. After noticing that a number of participants were reporting unusual skin rashes, the researchers focused on data from around 336,000 regular UK app users.
Researchers discovered that 8.8% of people reporting a positive coronavirus swab test had experienced a skin rash as part of their symptoms, compared with 5.4% of people with a negative test result. Similar results were seen in a further 8.2% of users with a rash who did not have a coronavirus test, but still reported classic COVID-19 symptoms, such as cough, fever or anosmia (loss of smell).
To investigate further, the team set up a separate online survey, gathering images and information from nearly 12,000 people with skin rashes and suspected or confirmed COVID-19. The team particularly sought images from people of colour, who are currently under-represented in dermatology resources.
17% of respondents testing positive for coronavirus reported a rash as the first symptom of the disease. In addition, for one in five people (21%) who reported a rash and were confirmed as being infected with coronavirus, the rash was their only symptom.
The study further revealed that the rashes associated with COVID-19 fall into three categories: ‘’Hive-type rash (urticaria): Sudden appearance of raised bumps on the skin which come and go quite 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 on in the infection, but can also last a long time afterwards.
‘’‘Prickly heat’ or chicken pox-type rash (erythematous-papular or erythematous-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 is most specific to COVID-19, is more common in younger people with the disease, and tends to present later on’’
Talking about their findings Dr Veronique Bataille, the lead author of the study, said: “Many viral infections can affect the skin, so it’s not surprising that we are seeing these rashes in Covid-19.
“However, it is important that people know that in some cases, a rash may be the first or only symptom of the disease.
“So if you notice a new rash, you should take it seriously by self-isolating and getting tested as soon as possible.”
Professor Tim Spector, who is running the Covid Symptom Tracker app, has also mentioned concerns of a rash being connected to coronavirus.