Diagnostic value of cutaneous manifestation of SARS-CoV-2 infection
AbstractImportanceSARS-CoV-2 causes multiple immune-related reactions at various stages of the disease, and the wide variety of cutaneous presentations has delayed linking these to the virus. Previous studies had attempted to look at the prevalence and timing of COVID-19 rashes but were mostly based on hospitalized severe cases with limited follow up.ObjectiveTo assess the diagnostic value of new skin rashes in SARS-CoV-2 infection.DesignObservational study including data collected longitudinally via the COVID Symptom Study app between May 7th and June 22nd, 2020, as well as data from an independent online survey on skin-related symptoms.SettingCommunity-basedParticipantsVolunteer sample of 336,847 UK users of the COVID Symptom Study app and 11,546 surveyees, aged 1 to 90 years old.ExposureUsers self-reporting a positive or negative SARS-CoV-2 swab test result, untested symptomatic users, and survey respondents.Main Outcome(s) and Measure(s)the diagnostic value of new skin rashes in SARS-CoV-2 infection, and observation on their duration and timing in relation to other COVID-19 symptomsResultsIn the app data, 8.8% of the swab positive cases (N=2,021) reported either a body rash or an acral rash, compared to 5.4% of those with a negative swab test (N=25,136). Together, these two cutaneous presentations showed an odds ratio (OR) of 1.67 (95% confidence interval [CI]: 1.42-1.97) for being swab positive. Skin rashes were also predictive in the larger untested group of symptomatic app users (N=54,652), as 8.2% of those who had reported at least one classic COVID-19 symptom, i.e., fever, persistent cough, and/or anosmia, also reported a rash. Data from the independent online survey showed that in 17% of swab positive cases, the rash was the initial presentation. Furthermore, in 21%, the rash was the only clinical sign.Conclusions and RelevanceSkin rashes cluster with other COVID-19 symptoms, are predictive of a positive swab test and occur in a significant number of cases, either alone or before other symptoms. Recognising rashes is important for the early detection of COVID-19 cases. To help healthcare professionals in this task we have established a large library of high-quality manually curated photos, available at: https://covidskinsigns.comKey pointsQuestionWhat is the diagnostiv value of the cutaneous manifestation of SARS-CoV-2 infection?FindingsWe confirmed, in a community-based setting, that the presence of a rash is predictive of SARS-CoV-2 infection, and provided a large library of cutaneous manifestation photos to help healthcare professionals in diagnosing COVID-19.MeaningSkin rashes should be considered as part of the clinical presentation of COVID-19 to aid earlier diagnosis and curb the spread of the infection.