Parosmia: The Long COVID Condition That Makes Everything Taste Or Smell Rotten

Parosmia distorts people's senses so much that even plain water can smell or taste like sewage or chemicals.
Experts are working to learn more about long COVID and parosmia, a condition that distorts taste and smell.
martin-dm via Getty Images
Experts are working to learn more about long COVID and parosmia, a condition that distorts taste and smell.

It’s been nearly a year since Natalia Cano got COVID, but she still posts regular TikTok videos about her experience. It’s far from over for her.

That’s because Cano, 20, has developed parosmia, a post-COVID condition that can make once-pleasant foods and scents smell and taste disgusting. Think sewage, garbage or smoke.

For Cano, coffee is nauseating. Water tastes oddly like chemicals. The fall air smells like garbage.

“Nothing makes sense. It’s completely arbitrary,” Cano said in a TikTok video that shows her trying to choke down a Clif bar to make sure she gets some protein and calories.

She’s not the only person sharing experiences with post-COVID parosmia on social media. And her lingering symptoms aren’t particularly rare, it seems.

“I wouldn’t hang my hat on any number that’s been put out yet,” said Ahmad Sedaghat, director of the University of Cincinnati division of rhinology, allergy and anterior skull base surgery, of attempts to quantify how common this condition is among people who’ve had COVID. “But I wouldn’t be surprised if it’s 15 to 20%.”

The parosmia-COVID connection

Parosmia occurs when a person’s olfactory nerves are damaged, ultimately changing how smells reach the brain. It has been linked to other viral infections, not just COVID.

But it makes sense that there appears to be a particular connection to the coronavirus because of how often it impacts infected people’s sense of smell. Estimates suggest anywhere between 50% and 75% of those with COVID lose their senses of taste or smell, likely because the virus damages their olfactory nerve and cells that support it.

The good news is that the vast majority of people regain their taste and smell senses within four weeks. But for many, the recovery process takes longer. And for some, it can seemingly go awry.

“We think [parosmia] happens as part of the recovery process to injure one’s sense of smell,” Sedaghat explained. As the damaged nerves and cells regrow and regenerate, there can be some “miswiring,” he said.

Sedaghat, who has been treating patients with post-COVID parosmia, believes this snarled wiring has a protective element to it, because disgust can help protect people from substances that pose a risk of infection. In other words, the olfactory senses and brain may working together to try and keep the body safe.

It’s just a theory at this point, “but it makes sense,” Sedaghat argued. “It’s consistent with what we know about evolutionary mechanisms.”

“For the people who are experiencing this, it can be a real, very serious change in how they’re relating to their own body.”

- Abigail Hardin, assistant professor at Rush Medical College

Getting help for parosmia

So far, there have only been a handful of studies on parosmia and COVID, so many people like Cano have turned to social media to seek answers and share their experiences. At the same time, the internet has offered some possible (and unproven) treatments, like eating a burnt orange to restore the sense of smell.

But there are some evidence-based treatment options for parosmia. Smell training is the go-to for people who lose their sense of smell for months, or who develop this particular condition, Sedaghat said, and it can be fairly involved.

The specific approach differs from person-to-person and from provider-to-provider, but the general idea is that people are asked to sniff particular odors (things like lemon, coffee, honey and more) for 20-ish seconds, several times over the course of several months. They then try to imagine what it used to taste or smell like to them.

“It’s a rigorous process,” Sedaghat said. He also encourages patients to seek out smells and tastes that they once enjoyed.

“My coffee smells bad? Don’t avoid it, because if you avoid it that connection can become permanent,” Sedaghat said. “While things are still plastic, I want patients to expose themselves to the things that are unpleasant.”

Of course, if your once-beloved morning coffee now smells like sewage to you, that’s easier said than done. And parosmia can be really challenging to cope with emotionally.

“Those kind of fundamental changes in how your body is functioning for you can be really disruptive ― functionally, emotionally, socially and in terms of vocation,” said Abigail Hardin, an assistant professor of psychiatry and behavioral sciences at Rush Medical College in Chicago who works with long-haul COVID patients. “For the people who are experiencing this, it can be a real, very serious change in how they’re relating to their own body.”

Hardin said those struggling with the emotional toll of changes to their senses of taste and smell might benefit from connecting with mental health professionals who focus on patients with hearing loss or chronic pain, which are somewhat analogous.

Sedaghat said the patients he’s worked with are heartened to at least get an explanation for what’s going on in their olfactory system and brain. They’re also relieved to know that parosmia, while absolutely devastating, is a sign that their brain and body are trying to recover after the virus. “It tells us regeneration is happening,” Sedaghat said.

Still, it is possible that some people with parosmia may never get back to normal. There’s simply too little known about long-COVID and its symptoms at this point to say.

Mental health experts like Hardin believe it’s true that healing can be helped simply by having a name for something as jarring and potentially traumatic as parosmia.

“When you’re able to have a diagnosis or name something, it does help alleviate a bit of the emotional pain associated with it,” Hardin said. “But that is then not sufficient. There’s more we need to do to help people cope long-term with this symptom that they may not know how long it will take to go away.”

Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.