Speech language therapist Hannah Eskridge, MSP, was sure she smelled something burning.
“I was in the clinic, and it smelled like someone had left a floor heater on,” she says, recalling a moment in early 2021.
No one else smelled it. Eskridge was experiencing the first disruption to her sense of smell caused by COVID-19, which she had been infected with eight months before, back in June 2020. She doesn’t recall whether she lost her ability to smell during her initial illness because her other symptoms were worse.
“I was pretty sick for about a week,” she says. “I wasn’t eating. Then, throughout the fall and winter, I experienced a variety of long COVID symptoms.”
Her headaches, brain fog and sharp pains in her hands, legs and feet were more concerning than changes to her ability to smell. But soon after she started smelling smoke, she began to taste ashes.
“I felt like I was eating an ashtray,” she says. “It was really quite a difficult symptom.”
A loss or disruption of the sense of smell is a well-known symptom of COVID-19, says UNC Health rhinologist Brent Senior, MD. As many as half of all people who had earlier variants of COVID-19 lost their sense of smell. With omicron and its subvariants, about 1 in 5 people lost their sense of smell.
“The good news is that people do recover,” Dr. Senior says. “But it can be quite disturbing for patients, especially since it’s unclear what the time frame is for improvement.”
Disruption to the sense of smell can happen to both vaccinated and unvaccinated people with COVID-19, but vaccinated people tend to have milder symptoms overall and are much less susceptible to serious illness.
COVID-19 Can Make It Harder to Taste Food
People with COVID-19 also report being unable to taste food, Dr. Senior says, but that problem may be caused by the inability to smell.
“Taste goes hand in hand with the sense of smell,” he says. “We haven’t found any damage to cells that directly support the sense of taste. But to really appreciate flavors, you need to be able to smell.”
On average, patients report losing their sense of smell for two or three months after they have recovered from other COVID-19 symptoms, Dr. Senior says. However, doctors don’t know yet how long it will take people infected with omicron variants to recover, though it appears to be shorter.
How COVID-19 Affects the Sense of Smell
Dr. Senior says that the virus that causes COVID-19 seems to affect cells that support the olfactory nerve, the nerve that transmits messages about smell to the brain. This nerve is found high in the nose. When the supporting cells are unable to remove toxins and provide nutrition to the olfactory nerve, then the messages about smell don’t get to the brain.
It’s not unusual for a viral infection to disrupt a person’s sense of smell, Dr. Senior says, but that’s typically because of nasal congestion, and less commonly from involvement of the cells around the olfactory nerve or damage to the nerve itself.
“The thing that is unusual here is the degree of loss of the sense of smell,” he says. “It’s almost complete loss and occurring in a large percentage of COVID-infected people and for a long time.”
Often, people with long COVID (symptoms continuing for months after the virus is gone), continue to experience a loss of taste and smell.
Some people recover their sense of smell only to lose it again or have it return with distortions, a condition called parosmia.
“It’s not infrequent that I hear of this from a patient,” Dr. Senior says. “Things that normally smell good seem to smell very bad to them. We don’t hear of parosmia with patients who lose smell from a cold or the flu.”
Eskridge said the ashtray taste in her mouth wrecked her appetite, “but at least when I ate, the food tasted like it was supposed to,” she says. “I read about a lot of people whose favorite foods started tasting awful.”
Children with COVID-19 Sometimes Lose Their Sense of Smell, Too
About a third of children who get COVID-19 lose their sense of smell, says UNC Health pediatric rhinologist Austin Rose, MD. Fortunately, “most children have a complete resolution of their symptoms within six months,” he says.
Typically, teens and children 10 and older notice a change in smell more than younger children who may have a harder time explaining these symptoms.
“Primarily what I hear from my patients is that they have an alteration instead of loss of smell,” Dr. Rose says. “They’ll say that things smell or taste unusual—maybe foods they normally like don’t taste good anymore. Fortunately, these symptoms usually improve over time.”
A concern for doctors and parents is that children won’t eat enough while their sense of smell is altered, Dr. Rose says, but none of his patients have had serious nutritional problems due to this symptom of COVID-19.
Getting Your Sense of Smell Back After COVID-19
If you lost your ability to smell normally because of a COVID-19 infection, your doctor might suggest nasal sprays or steroid pills that help the cells supporting the olfactory bulb recover faster.
“We don’t have a way of preventing it just yet,” Dr. Senior says, “so we are trying to find treatments that might bring the sense of smell back sooner.”
One strategy that doctors around the world are trying is “sense of smell retraining.” This method was in use for other illnesses before COVID-19, Dr. Senior says, and helps your brain associate smells with objects.
Here’s how it typically works: Patients choose four odors that are distinct, strong, pleasant and familiar, such as a rose, a lemon, coffee or cinnamon. They smell these odors, one at a time, for a minute or two each, a couple of times a day.
“We’ve had encouraging results with sense of smell retraining,” Dr. Senior says. “The more often patients are able to do that kind of treatment, the more likely they are to regain their sense of smell. However, it can take months and patients have to be persistent.”
Because of the need for time and patience, sense of smell retraining is used less often with children, Dr. Rose says.
Dr. Senior recommended that Eskridge use sense of smell retraining. He also prescribed irrigation of her sinuses with a steroid solution twice a day for a month, she says. She did sense of smell retraining twice a day, too.
“I don’t know if it was the smell therapy or irrigation or both,” she says, “but the problems seem to have gone away.”
A Sense of Smell Is Important to Health and Safety
Dr. Senior says that losing your sense of smell can have a huge impact on your quality of life.
“It’s the impact on the individual that’s concerning,” he says. “Your sense of smell is so important to daily life. It’s not only an enjoyable sense, but it also helps keep us safe. We smell food to know if it’s safe to eat. We smell a gas leak and know to get out. It’s hard to enjoy a meal if you don’t have a sense of smell.”
“When you go through something like this,” she says, “it makes you appreciate the things you took for granted.”
If your sense of smell is not as strong as it used to be, or things have started to smell different from what you expect, speak with your doctor, or find one near you. If you think you may have long COVID-19, talk to your doctor or contact the UNC COVID Recovery Clinic at (984) 974-9747.