What’s in a nose? Smell training may help recovery from Covid-19 anosmia

Otolaryngologists treating Covid-19 patients with impaired smell are finding success with a whiff of intense odors like cloves, eucalyptus, rose, and lemon.

Covid-19 symptoms range from a headache or dry cough to a bout of fevers or chills. And sometimes a sore throat or muscle aches. Telling those symptoms apart from the common cold, flu, or allergies has put many on-edge. But one symptom has stood out as a clear Covid sign — the loss of smell and with it, taste.

Losing your sense of smell is called anosmia – and it affects a large number of Covid patients.

Dr. Waleed Abuzeid, an Associate Professor of Otolaryngology at the University of Washington, says that roughly 90% of people who contract Covid-19 experience some kind of smell loss or impairment. However, only half of them can tell.

"You don't realize the impact until it's actually gone," he said. "Everything starts to taste very bland."

Sweet, salty, bitter, or sour flavors may linger because the tongue can sense them, but the overall nuance of flavor is gone.

Smell loss can also prevent patients from noticing smoke, rotten food, or gas leaks. Our sense of smell helps us react and prevent dangerous situations.

Dr. Abuzeid says about 95% of his patients will recover after two weeks. But there are those who experience smell and taste loss for much longer, or seemingly permanently. Those are the patients that he treats most often. For them, he uses an olfactory training, kind of like a scratch and sniff of strong familiar smells.

Here's how it works: twice a day for about 20 seconds you smell an essential oil like cloves, eucalyptus, rose, and lemon. Those are the smells used in clinical studies, but Dr. Abuzeid also tells his patients to train with other familiar smells.

"Pick four smells that are very familiar to you," he said. "You remember what they used to smell like, use those to train your brain."

Olfactory or smell training may help by strengthening and repairing damage to smell fibers in nasal passage.

"You actually start to improve neuronal connections," Dr. Abuzeid said. "The part of your brain that processes smell.”

Abuzeid says he does not recommend smell training after immediately losing your smell. But it's something to consider or ask your doctor about if you endure smell loss beyond two weeks. Many patients will see improvement after one month, but Abuzeid says that smell training can take as long as three months.

Covid-19 has created a path to learn more about all the ways our sense of smell works and can be repaired. Dr. Waleed Abuzeid says he looks forward to other kinds of treatments as we catch up research on olfactory senses.

"As that knowledge of how sense of smells works improves, we're going to be able to better target therapies to improve sense of smell or smell loss--whether it's from Covid or anything else."