Sense of smell as an intimate bearing with taste and appetite, often smell induces appetite and anosmia will rob people from the pleasure of enjoying food.
Loss of smell and taste are some of the early and common symptoms of Covid that stays even after recovery in some cases. (Reuters Image, Representative)
A receding sense of smell has become the most prominent symptom for new Covid-19 cases. Sometimes this is the most prevalent symptom often accompanied by an inability to taste. Loss of smell, also termed anosmia or smell blindness is often the first and the only symptom among Covid positive people and occurs quite abruptly, all of a sudden like switched has been tapped. Most regain their lost senses after recovery or usually in few weeks from testing positive but in few patients, the loss is not recovered and the doctors cannot assure when it will return or if it will at all.
Scientists know little about how the virus causes anosmia that stays even after recovery and what is more alarming is there is no cure yet. Such cases of persistent anosmia are pilling and the experts now fear that even when the pandemic ends a huge number of people will be left with permanent loss of sense of smell and taste.
Sense of smell as an intimate bearing with taste and appetite, often smell induces appetite and anosmia will rob people from the pleasure of enjoying food. This can also impact their mood and quality of lifestyle. Smell signals give depth to social interactions and studies show that loss of smell can cause a strange sense of detachment, inability to feel pleasure and anhedonia. It more or less makes the world two dimensional.
British scientists while studying 9, 000 Covid-19 patients who joined a support group on Facebook found loss of smell has made them lose interest in eating and socializing. . This has even affected relationships with their associates.
Smell also serves as an alarm system alerting people of impending danger like during a gas leak or recognizing stale or burning food on stove etc.
Why some recover and for other’s the loss persists
Viral load is a key factor to determine if a Covid patient is more susceptible to long-term anosmia. According to s study by the Harvard Medical school, for Covid-19, when the SARS-CoV-2 invades cells, it causes inflammation that knocks out the sense of smell. So the recovery time is related to how long the surrounding cells will take to heal. But in some cases, the inflammation is so much that it damages nearby olfactory neurons as well that takes time to heal depending on the supply of stem cells within the nose lining. In rare cases, the neurons are permanently damaged hampering sense of smell forever.
As the olfactory system starts healing, a strange condition called parosmia can also happen in which the smell returns in a distorted fashion. Several patients in a Facebook group has reported that their favourite food smells like a dingy room or dead fish. According to some scientists, this happens when olfactory neurons misconnects with brain cells responsible for smell, but why this happens in some people is yet to be determined.
Can anosmia be treated?
Although no cure has been found, smell training that involves sniffing essential oils like rose, clove, lemon, eucalyptus oil for 20 seconds every day can help in some cases to regain the sense of smell. However, scientists say this is unlikely to help in the most severe cases of anosmia. Regeneration is a slow process and can take time.