‘Olfactory training’ can help COVID patients regain smell, studies say: ‘You may have some level of control’

DAVIS, Calif. (Nexstar) — Over a year into the coronavirus pandemic, COVID-19 “long-haulers” may be feeling a sense of urgency about their sense of smell.

Recent studies estimate that about 10% of COVID-19 patients experience lingering, persistent symptoms, including respiratory issues, fatigue, headaches or even brain fog. But another one of the most common side effects — loss of smell — may be just as upsetting.

“If you had to choose a sense to lose, most people would probably pick smell loss,” said Dr. Toby O. Steele, of UC Davis Health. “But when it’s gone, you’re not enjoying food, you’re losing weight. You can’t detect whether the milk is spoiled. … It’s a huge driver of quality of life.”

Steele is an assistant professor in the Department of Otolaryngology Head and Neck Surgery, where he specializes in sinonasal and skull-base disorders. He also works with patients from UC Davis Health’s new post-COVID-19 specialty clinic, which specifically aims to study and treat patients with symptoms that seem to persist for months, and often even longer.

“I still have patients who still have persistent smell or taste disfunction a year out,” Steele said.

Based on studies, Steele says UC Davis Health estimates that smell loss, or anosmia, affects between 5% and 10% of all COVID patients — and not just the “long-haulers” with persistent symptoms. Some simply suffer from a reduced ability to smell, known as hyposmia or microsmia, while others experience even stranger symptoms, such as smelling an odor that isn’t there or having a smell be “distorted” by the brain.

“Many people are finding an alteration in their sense of smell,” Steele said. “They don’t enjoy their frosted flakes anymore, or the scents that they loved, they can no longer stand the smell of. That’s important for people to know, because it can be alarming.”

Loss of smell, however, isn’t a symptom that only COVID patients experience. “Post-viral olfactory loss” can present in flu patients or those with especially severe respiratory infections, Steele said. But after the COVID-19 pandemic brought the issue to light, there’s more interest in treating it.

“It’s the silver lining in the COVID-19 pandemic,” said Steele. “Smell and taste disorders, prior to the pandemic, took more of a backseat. Now, we have more time, more money from the federal government to research identifying mechanisms … or potentially therapeutic or treatment options.”

To that end, Steele has been working with fellow faculty members, including UC Davis professor Qizhi Gong, Ph.D, among others, to identify treatments for those experiencing loss of smell. So far, Steele has observed favorable results with an approach that treats two different mechanisms by which a patient can lose their sense of smell: the conductive pathway and the neural pathway. Issues that affect the former generally tend to inhibit olfactory receptors in the nasal cavity, while issues that affect the latter inhibit the brain’s ability to recognize the signals from those receptors.

“This is where olfactory training may help,” said Steele, who recommends a two-pronged approach. First, he suggests buying four different essential oils — lemon, rose, clove and eucalyptus — and smelling each for 10 seconds twice a day.

“You’re looking at the odor, you’re telling your brain, ‘This is rose,’ and you’re trying to reestablish that neural connection,” he said, citing studies that show between 30% and 40% of patients who practice this method recover some sense of smell within three to six months.

Steele pairs this treatment with a nasal rinse containing Budesonide, a prescription anti-inflammatory.

“That part doesn’t make a ton of sense,” he admits. “We don’t think COVID affects the conductive pathway. But what the medicated rinse is doing setting up an environment in which those smell nerves are going to succeed.”

Together, these two methods result in “significantly better” recovery, with research showing “40% or 50%” of patients showing improvement three to six months, Steele said.

Of course, patients can also hope for “spontaneous recovery,” or essentially doing nothing and waiting for their sense of smell to return. Steele said there’s a “good chance” this may work, seeing as about two-thirds of patients who suffer from anosmia after recovering from other respiratory viruses regain their smell within a year.

“But with COVID, we don’t know,” he said.

The best course of action, Steele said, is to talk to a primary care doctor about possible treatments or make an appointment to see an ear, nose and throat specialist to discuss anti-inflammatory rinses. But he’s equally as passionate about olfactory training and urges those with smell loss to head to the store, buy some essential oils and give it a shot.

“You may have some level of control over this outcome, and I think that is a motivating factor,” he said. “And don’t give up. If you’re not seeing results right away, don’t give up. Because it can take time.”