Losing Your Sense of Smell and Covid-19: What It Means
Recent research suggests this symptom may be just as common as loss of taste—but it might indicate a milder case of Covid-19.
Why smell matters
By now you’re likely well-versed in the symptoms of coronavirus: fever, chills, shortness of breath, and the sudden loss of taste, to name a few of the primary ones. Research published in a January 2021 issue of the Journal of Internal Medicine suggests another should be added to the list when it comes to mild cases of the virus: The loss of smell.
Here, experts explain what you need to know if this happens to you and why the virus may cause the body to react this way.
How Covid-19 can affect your sense of smell
What’s clinically referred to as anosmia, or “the loss of the ability to smell, is a direct reflection of the affinity for the virus to attack accessory olfactory neurons,” says Chris Colbert, DO, assistant program director of the emergency medicine residency program at the University of Illinois at Chicago. The olfactory nerve is one of a dozen nerves in the skull specifically associated with your sense of smell. “The ongoing collection of data provides significant evidence that the Covid-19 virus has an affinity for these specific accessory cells,” Dr. Colbert says.
In the Journal of Internal Medicine study, European researchers looked at 2,581 patients diagnosed with Covid-19 between March and June 2020, collecting data at the beginning of infection through two months post-diagnosis. Out of this group, 1,1916 patients reported a loss of smell as a symptom of the virus. What’s important to note, however, is that 85 percent of those who lost smell had a mild form of the virus. Only about 5 percent of patients experiencing moderate to severe forms of it. (Here’s what you need to know about Covid-19 and autoimmune conditions.)
Why loss of smell happens
Aside from those who have a mild case of infection, those who may be more prone to dealing with anosmia may have preexisting issues with their nasal cavity. “MRI imaging has shown some abnormalities in the nasal passages in patients with Covid-19 infections,” says David Erstein, MD, a New York board-certified allergist and immunologist with Advanced Dermatology PC.
Research published in Academic Radiology looked at 23 patients diagnosed with coronavirus experiencing loss of smell. Of those patients, 73 percent had deficits in their olfactory structures, leading to diminished airflow through nasal passages. Other defects included abnormalities in the shape of the olfactory bulbs, which are structures in the brain involved in the sense of smell, and issues with the signal intensity between the brain and olfactory nerves. (Read the first-person account of one Covid-19 long hauler who lost her sense of smell.)
How long loss of smell lasts
Every patient is different. But the Journal of Internal Medicine research found that 95 percent of the patients in the study regained their sense of smell within six months. Additional research suggests that smell returns in eight days to four weeks, on average, says Dr. Erstein.
“There aren’t any profound negative impacts on our health from losing sense of smell,” says Dr. Erstein. “But losing sense of smell can be an indicator for underlying health conditions.” This means that if you’re experiencing a sudden loss of smell even with no other symptoms, it’s best to get tested for Covid-19 or other health concerns.
If your test is negative and loss of smell persists, see your primary care physician to rule out a separate condition like an infection or deviated nasal septum. (Learn 9 medical reasons you may be losing your sense of smell.)
Most Covid-19 patients will deal with the loss of smell
Both Dr. Colbert and Dr. Erstein say more research is needed to understand why a loss of smell is associated with milder cases of the virus. But a majority of Covid-19 patients will experience some form of anosmia and/or loss of taste, according to research published in JAMA Otolaryngology–Head & Neck Surgery.
The study found that 89 percent of those with mild symptoms of Covid-19 regained their sense of smell and/or taste within four weeks or noted significant improvement. The study also found that persistent loss of smell and/or taste was not associated with persistent coronavirus infection. In other words, even if other symptoms lingered while the virus was still in a person’s system, the loss of smell and taste were one of the first symptoms to clear up. (Learn more about these 11 other troubling Covid-19 symptoms and complications.)
What to do if you experience loss of smell
It’s important to note that many viruses can cause temporary loss of smell. The difference is that anosmia is often caused by a nasal obstruction from the virus, such as a stuffy or runny nose. Up to 40 percent of those with infections like the common cold or flu experience loss of smell, according to research published in Taste and Smell. The study found that women are more prone to these symptoms than men.
Previously, a loss of smell may not have been a reason to worry. But now it’s important to be on the lookout for other red flags that indicate a coronavirus infection. Contact your doctor at the first sign and stay home to avoid possibly spreading the disease to others. There’s no hack to regain your sense of smell quickly. But you can do your part to avoid getting the virus to begin with by washing your hands frequently, wearing a mask, and practicing social distancing.
Next: Here are 19 coronavirus myths you should stop believing.
- Journal of Internal Medicine: "Prevalence and 6‐month recovery of olfactory dysfunction: a multicentre study of 1363 COVID‐19 patients"
- Chris Colbert, DO, assistant program director of the emergency medicine residency program at the University of Illinois at Chicago
- David Erstein, MD, New York board-certified allergist and immunologist working with Advanced Dermatology PC
- Academic Radiology: "Olfactory Bulb MRI and Paranasal Sinus CT Findings in Persistent COVID-19 Anosmia"
- JAMA Otolaryngology – Head & Neck Surgery: "Evolution of Altered Sense of Smell or Taste in Patients With Mildly Symptomatic COVID-19"
- Taste and Smell: "Olfactory Disorders following Upper Respiratory Tract Infections"