Using data collected as part of the COVID symptom app study, a team from Kings College, London have suggested that the occurrence of skin rashes in conjunction with other COVID-19 symptoms are predictive of a positive swab test for the virus.
Between 7 May and 22 June, of the 336,847 UK users who registered with the app, 6403 reported that they had skin symptoms. Among those who had tested positive for COVID-19, 8.8% reported skin-related changes and these individuals were generally older (mean age 50.2 years) and slightly more likely to be women.
Interestingly, in patients with classic COVID-19 symptoms not tested, a similar proportion (8.2%) also reported a rash. In an attempt to better understand the nature of the skin problems, the team collected photographs from patients. The rashes were categorised as erythemato-papular, erythemato-vesicular types, urticarial and acral. The rashes appeared as the same time as other COVID-19 symptoms in most patients (47%), afterwards in over a third (35%) whereas in 17%, the rash appeared prior to the onset of symptoms. Furthermore, in 21% of those testing positive, the rash was the only symptom.
The authors concluded that their study strongly supports the inclusion of skin rashes in the list of suspicious COVID-19 symptoms to help identify cases of the infection.
Bataillie V et al. Diagnostic value of skin manifestations of SARS-CoV-2 infection. medRxiv 2020.07. https://doi.org/10.1101/2020.07.10.20150656