Facial flushing in covid-19: subclinical characteristic unrecognized and invisible to the naked eye

Early diagnosis of coronavirus disease 2019 (COVID-19) is crucial for disease treatment and control. The clinical characteristics in patients infected with COVID-19 most commonly manifest fever, cough and fatigue, which in some patients can be accompanied by runny nose, headache and other symptoms. Additional symptoms such as diarrhea are less common. All research about the clinical characteristics of COVID-19, none of COVID-19 research mentioned that facial flushing was a clinical feature that could be found. The invisible facial flushing, unrecognized clinical sign with the naked eye could be detected by the smartphone application in the COVID-19 patients. This novel screening tool for COVID-19 patients will be potential for early diagnosis and may be used in conjunction with thermoscan camera as front line screening and diagnostic capacity. It will help all medical service providers the effective screening tool for the recognition and early diagnosis before performing CT scans and real-time RT PCR (rRT-PCR) assays, especially in some health care facilities where could not be performed due to lack of laboratory support. Furthermore, application in active case finding for COVID-19, the key actions to stop transmission is challenging in countries with community transmission.