Is Loss Of Smell And Taste A Symptom Of COVID-19? Here’s What You Need To Know

As of 20 April 2020, the coronavirus cases have increased to 2,415,294 and have caused 165,192 deaths worldwide. In India, the confirmed cases have risen to 17,265 and caused 543 deaths.

The researchers and scientists from all around the world are continuously studying the coronavirus and every single day a new study is emerging about the virus. Much recently, a study reported that loss of either smell or taste may be an early warning sign of coronavirus disease (COVID-19).

Health experts have been saying that cough, fever and sore throat are the most common symptoms to look out for after contracting coronavirus. But, The American Academy of Otolaryngology-Head and Neck Surgery and the British Association of Otorhinolaryngology are now recommending that loss of smell (anosmia) and loss of taste (dysgeusia) should be added to the list of primary screening symptoms of COVID-19 [1].

What Is Loss Of Smell (Anosmia)?

Anosmia is the complete loss of smell; people who have anosmia can taste sweet, salty, bitter, and sour substances but can't specifically tell the difference between specific flavours. The ability to tell the difference between flavours depends on smell and not on the tongue [2].

The most common causes of anosmia are head injury, viral infections and Alzheimer's disease.

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What Is Loss Of Taste (Dysgeusia)?

Dysgeusia is the loss of taste and people with dysgeusia usually complain of a metallic taste and an unpleasant sweet, bitter or salty taste. The most common causes of dysgeusia are cold, postnasal drip, pregnancy, dry mouth, smoking, allergies, nutritional deficiencies, migraine, constipation and gastrointestinal infection [3].

How Is Loss Of Taste Or Smell Linked To COVID-19?

As per a study loss of smell and taste has been anecdotally linked to COVID-19 infection. In a study published in the journal International Forum of Allergy and Rhinology, researchers at UC San Diego Health reported that sensory loss is associated with the novel coronavirus [4].

During the study, the researchers surveyed 1,480 patients who had flu-like symptoms and underwent testing for COVID-19 infection. Out of the total, 102 patients tested positive for coronavirus and 1,378 tested negative. The COVID-19 patients had a mild form of the disease and did not require hospitalisation.

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The study findings showed that there was a high prevalence of certain sensory impairments in positive COVID-19 patients and the loss of smell and taste was intense and not mild. The researchers also pointed out that the rate of recovery of smell and taste was high and occurred usually within two to four weeks of the COVID-19 infection.

"Based on our study, if you have smell and taste loss, you are more than 10 times more likely to have COVID-19 infection than other causes of infection. The most common first sign of a COVID-19 infection remains fever, but fatigue and loss of smell and taste follow as other very common initial symptoms," said Carol Yan, MD, an otolaryngologist and head and neck surgeon at UC San Diego Health.

She further added that, "We know COVID-19 is an extremely contagious virus. This study supports the need to be aware of smell and taste loss as early signs of COVID-19."

The UC San Diego Health has recommended that loss of smell and taste should be taken into consideration while testing patients for COVID-19.

However, the exact mechanism of loss of smell and taste in COVID-19 patient needs to be further studied.