Parosmia Is a Post-COVID-19 Side Effect That Can Distort Your Sense of Smell

The unpleasant smell misperception can occur long after you've had COVID-19.

Loss of sense of smell is one of the most common symptoms of COVID-19, per the Centers for Disease Control and Prevention (CDC). But some people with COVID-19 experience another smell-related complication: a smell distortion called parosmia.

"While anosmia is a complete loss of smell and hyposmia is a decreased sense of smell, parosmia is an alteration of the sense of smell," Seth Lieberman, MD, assistant professor in the department of otolaryngology at NYU Langone Health, told Health.

About 10% of people who experienced olfactory (smell) issues during COVID-19 may develop parosmia as they begin to recover, per an April 2022 paper published in the journal Foods.

The "COVID smell" typically occurs two to three months after you had COVID-19, even if you didn't lose the sense of smell when you had the disease, per a February 2022 paper published in the journal Current Opinion in Otolaryngology & Head and Neck Surgery. But it can also start earlier, per a July 2022 paper published in the journal Laryngoscope.

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How Does Parosmia Change Your Sense of Smell?

The smell distortion is not a change for the better. People with parosmia say that everything smells unpleasant, even rotten or disgusting. "A piece of fruit may smell like chemicals, or even worse, like fecal matter," Dr. Lieberman said.

According to the July 2022 paper, parosmia is a "misperception of odors (such as perception as rotten or burnt odor)." Its causes include upper respiratory tract infections, head trauma, and neurodegenerative diseases such as Alzheimer's disease. Foods like coffee, onion, meat, citrus, or garlic can trigger parosmia attacks, per the February 2022 paper.

Parosmia often develops shortly after anosmia and/or hyposmia—and it's been shown to develop after COVID-19. The olfactory condition can greatly affect a person's quality of life, per the July 2022 paper.

Can You Get Parosmia After COVID-19?

Parosmia affects some people with COVID-19, but's not a symptom of the early stage of the disease. Parosmia may be a sign that you've recovered from COVID-19 completely, per the April 2022 paper.

Parosmia is not common in people who've had COVID-19 overall. But it is common among those who've experienced smell issues during COVID-19—about 64% of participants in the July 2022 paper with post-COVID-19 smell dysfunction had parosmia.

"It is believed to be due to an impact of the infection on the olfactory nerves' ability to interpret odors and aromas, and it can be seen in the aftermath of other types of viral infections," Charles Bailey, MD, medical director for infection prevention at Providence Mission Hospital and Providence St. Joseph Hospital in Orange County, California, told Health.

Can Parosmia Be Treated?

Recovery of sense of smell seems to depend to some extent on nerve regrowth, Dr. Bailey said. That means there may be little that can be done to accelerate the process.

The July 2022 study showed that Modified Olfactory Training (MOT) for 36 weeks was effective in treating post-COVID-19 parosmia. This training involved smelling certain scents—such as those of eucalyptus, lemon, clove, and rose—multiple times for 10 seconds with a 10-second breaks in-between. The training took up five minutes and was meant to be performed twice a day. The selected scents changed every 12 weeks.

An April 2022 paper published in the British Medical Journal (BMJ) noted that "there are currently no effective, evidence based treatments for patients with parosmia." But they did offer some practical management tips for those with the smell distortion:

  • Keep track of foods that trigger your parosmia and let the people around you know what they are.
  • Because parosmia triggers can change, keep trying new things to find what your "safe" foods are.
  • Consider eating foods that are cold or at room temperature—they give off less odor.

Parosmia can greatly affect people's experiences with food and other smells, and it may last for a while. The April 2022 BMJ paper recommended being open about the condition to others so they can support you in avoiding major triggers. And remember that parosmia severity can fluctuate and make you feel worse some days than others. These fluctuations even out eventually.

If your parosmia is severe enough that you can't eat most or any foods, talk to a healthcare provider or dietitian.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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