Scientists are urging the government to add skin rashes to the list of coronavirus symptoms after one in 11 people show signs.
More than 20,000 people were part of the study by Kings College London, which made the startling discovery.
Those who were part of the data set either tested positive for Covid-19 or were heavily suspected of having the virus.
Nine per cent of those infected also suffered from skin rashes and eight per cent of people with other tell-tale symptoms also had the skin problem.
Fever, continuous cough and loss of smell or taste are the only three symptoms officially recognised by the NHS.
Anyone with any one of the three are told to get tested and self-isolate.
Data was taken from the Kings College Covid Symptom Tracker app, which has more than 300,000 users.
Lead researcher Dr Mario Falchi said Covid-19 patients reported suffering from the rashes for weeks - which is much longer than the three NHS symptoms.
Writing in the study, Dr Falchi said: '"Covid-19 rashes may present in many forms and at different stages of the disease.
"Although, it is less prevalent than fever, it is more specific of Covid-19 and last longer.
"An increased awareness from the public and healthcare professionals regarding Covid-19 skin changes will allow more efficient identification of new and earlier clusters of the disease."
Professor Tim Spector, an epidemiologist at Kings College, told MailOnline last month that Britain was missing 'the majority of cases' because it was 'out of line with the rest of the world'.
He told the Evening Standard: "It's looking like it is predictive of having a positive [coronavirus] test and GPs are unaware of it, so they are sending people away, or NHS 111 is not recognising it as a possible symptom.
"It's usually in combination [with other symptoms] but it can come on at different times, sometimes after the other symptoms.
"It can come two weeks after the other symptoms, or two weeks before. It's just being missed because the public is unaware of it and doctors are unaware of it."