“Smell training” best for COVID-19, experts say

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Smell training should be used in lieu of corticosteroids to treat smell loss caused by the novel coronavirus (COVID-19), according to a group of experts from the University of East Anglia, who published a review in the journal International Forum of Allergy and Rhinology.

Smell loss is a prominent symptom of COVID-19, affecting one in five patients, which may continue long-term for some patients, the researchers said. While commonly treated with corticosteroids, a class of drug that lowers inflammation in the body, the researchers do not recommend them for COVID-19 smell loss.

Instead, the team recommended “smell training,” a process that involves sniffing at least four different scents or odors twice a day for several months. It aims to help recovery based on neuroplasticity, the brain's ability to reorganize itself to compensate for a change or injury, the authors said.

The team carried out a systematic evidence-based review to see whether corticosteroids could help people regain their sense of smell. They found that there is very little evidence that corticosteroids will help with smell loss. Additionally, because they have well known potential adverse side effects, the researchers said they advise that they should not be prescribed as a treatment for post-viral smell loss.

Most people who experience smell loss because of COVID-19 will regain their sense of smell spontaneously, the authors said. Research shows that 90 percent of people fully recover their sense of smell after six months.

Smell training could be helpful as a cheap, simple and side-effect free treatment option, the researchers said.

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