A skin rash can be the only symptom shown on people infected with COVID-19, a new study has found.

Researchers at King’s College London said skin rashes and ‘COVID fingers and toes’ can occur in the absence of any other symptoms, and should be considered as key diagnostic signs of the virus.

Data collected from 336,000 people on the COVID Symptom Study app revealed that 8.8 per cent of people testing positive for the disease in the UK had experienced skin rash.

An additional online survey of nearly 12,000 individuals with skin rashes found that 17 per cent of those with COVID-19 reported a rash as their first symptom of the disease. About one in five (21 per cent) of the people who were diagnosed with the virus had rash as their only symptom.

The rashes can come in three forms: hive-type rash with itchy, raised bumps; chickenpox-type rash with small, itchy red bumps; and ‘COVID fingers and toes’ with sore, reddish or purplish bumps on fingers or toes.

“Many viral infections can affect the skin, so it’s not surprising that we are seeing these rashes in COVID-19,” said Dr Veronique Bataille, consultant dermatologist at King’s College London and the study’s lead author.

“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.”

The recognised symptoms of COVID-19 by the World Health Organisation currently include fever, tiredness and dry cough along with loss of taste or smell, skin rash and discolouration of fingers or toes.

This article originally appeared on Over60.