If you have recently seen a patient who had a reduced or missing sense of smell or taste without having another respiratory disorder, you aren’t alone—and you may have encountered a COVID-19 carrier without realizing it.
According to ENT UK, the professional membership body representing ear, nose, and throat surgery in the United Kingdom, and the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS), there has been an anecdotal spike in the number of patients presenting with anosmia, hyposmia, and dysgeusia that are unconnected to a corresponding respiratory disease such as allergic rhinitis, acute rhinosinusitis, or chronic rhinosinusitis who then ultimately tested positive for the coronavirus, even though they showed no COVID-19 symptoms. AAO-HNS recommends that anosmia be added to the list of screening symptoms for potential COVID-19 infection.
ENT UK described the connection in a letter to its membership, stating that previously described coronaviruses are thought to account for 10% to 15% of anosmia cases. “Indeed, human coronaviruses have been shown to be capable of neuro-invasion via the olfactory epithelium and olfactory bulb,” explained Claire Hopkins, BMBCh, MA FRCS(ORLHNS) DM(Oxon), president of the British Rhinological Society to ENTtoday. “There are a number of studies reporting in the press (but not yet in peer reviewed literature) suggesting as many as two in three patients known to be positive with COVID-19 report loss of or a reduced sense of smell.”
Through recent discussions on the American Rhinologic Society discussion board, Dr. Hopkins noticed a distinct uptick in her own practice and among fellow ENT surgeons in young, otherwise asymptomatic patients presenting with anosmia. “I realized that as I was seeing these patients in clinic that I was placing myself at risk, as not only is nasal endoscopy an aerosol-generating procedure, but also that these patients did not meet criteria to self-isolate and were therefore likely to be transmitting infection to others. Indeed, yesterday, a surgical colleague was tested on the basis of isolated anosmia for 72 hours, tested positive, and is therefore self-isolating,” she said on the discussion board.
Dr. Hopkins has collected clinical data from the large number of patients who have reached out to her for advice. (She has submitted this data to JAMA for publication.) “Half do not meet the current [COVID-19] diagnostic criteria of a cough or high fever, and one in six have no other symptoms except for their anosmia,” she said.
Given this correlation, and the reports that corticosteroid use may increase the severity of infection, ENT UK advises against using oral steroids to treat new onset anosmia, particularly if it’s unrelated to head trauma or nasal pathology. In addition, ENT UK advocates avoiding the use of endoscopy in non-urgent cases due to the high risk of transmission but notes that it’s particularly important to use full personal protective equipment if endoscopy is considered necessary in patients with anosmia.