COVID-19 Symptom: Loss of Sense of Smell and Taste

Infectious disease specialist Dr. Judy Stone relates a story of a friend in Italy, citing loss of sense of smell and taste as the most unusual symptoms of coronavirus (COVID-19) infection. 

This note from Stone came after Utah Jazz Center Rudy Gobert posted on his Twitter last March 23 that he hasn't been able to smell anything the past 4 days. Gobert was confirmed positive with COVID-19. Last week, another celebrity, Frozen 2 actor Rachel Matthews, reported that she experienced a loss of sense of smell and taste on the 4th day of her quarantine as a positive COVID-19 patient. 

According to Dr. Stone, her friend confessed that her symptoms included fatigue, fevers, and cough. Her most peculiar symptom, however, was that she could not smell and taste a thing. She could not smell the bleach when she sanitized the house, the garlic when fried, or the strong smell of fennel. Fortunately, her friend survived the disease.

Physicians in Italy also reported that a significant proportion of their COVID-19 patients have also lost their sense of smell and taste.

A warning sign to self-isolate 

The anecdotal evidence led a group of British ear, nose, and throat physicians to give an advisory over the weekend to ask all adults with sudden anosmia (the medical term for a loss of smell), even if void of other symptoms, to self-isolate in seven days.

The group of doctors said, "We might be able to reduce the number of otherwise asymptomatic individuals who continue to act as vectors, not realizing the need to self-isolate".

Medical personnel who are treating people with anosmia are advised to use personal protective gear and refrain from doing nonessential procedures as these precautions are urgent, the doctors warned. This advice is crucial because the virus replicates in the nose and the throat, and an exam can prompt cough or sneezes that expose the doctor to a high level of virus, the president of the British Rhinological Association stated.

The American Academy of Otolaryngology also issued a similar warning to their colleagues in Great Britain: the absence of allergies or sinusitis, the loss of smell or taste should be used as a screening tool for potential COVID-19 infection. The said symptoms also "warrant serious consideration for self- isolation, and testing of these individuals." they add.

According to Dr. Stone, a plausible biological explanation for the loss of sense of smell and taste when inflicted with COVID-19 is that viruses destroy cells or cell receptors in the nose. Other viruses infect the brain via the olfactory sensory nerves. In a study published in the Journal of Medical Virology published last February 27, it was concluded that some coronaviruses could attack the brainstem via a synapse‐connected route from the lung and airways. The attack of the said virus may be one reason for acute respiratory failure.

People who recover from COVID-19 are reported to regain their sense of smell and taste, although it would take several days or weeks.