Christine Giordano, MD | Reviewed by Angela Dunn, MD, MPH, August 29, 2023 GoodRX

Key takeaways:

• Many people experience changes in taste and smell after COVID-19 infection. 
• Changes in smell include a complete loss of smell (anosmia), distorted smell (parosmia), and smelling things that aren’t there (phantosmia).
• For most people, changes in smell go away after a few weeks. But they can last for many months. 
• Parosmia can be very difficult to live with, but there are ways to help manage the symptoms.

For some people, morning coffee smells like onions or trash. And the smell of loved ones makes them want to gag day after day. This is parosmia — a change or distortion of normal smell. And it’s one of the types of smell changes that people experience after a COVID-19 infection. 

Changes in smell (and taste) are very common both during and after COVID. In fact, almost half of people with COVID report a change in their sense of smell or taste. This can show up in different ways. Some people experience a partial or total loss of smell. And some can smell bad smells that aren’t there.

Changes in smell usually go away within a few weeks without treatment. But sometimes the symptoms last much longer. And daily life can become distressing when smell changes drag on. 

Scientists are still trying to figure out why parosmia and other smell changes happen after COVID — and why they affect some people and not others. There’s no magic cure. But some treatments, like olfactory training, can help speed up your recovery.  

What is parosmia?

Parosmia is an unpleasant change to normal smell. Typically, things that used to smell good will smell horrible. Phantosmia — smelling something that isn’t there — is a different but similar change. Smoke is one of the most common smells that people identify, including tobacco smoke and smoke from a fire.

Along with total or partial loss of smell (anosmia and hyposmia), parosmia and phantosmia are types of olfactory dysfunction. This is a complicated term that describes a problem with your sense of smell. 

And all seem to be complications of COVID. While anosmia and hyposmia tend to happen early on in the infection, parosmia is different. 

Some people experience parosmia within 1 week of the start of COVID symptoms. But it more commonly starts weeks or months after the initial COVID infection. And some people have problems up to 6 months later. 

What does COVID parosmia feel like?

People who experience this so-called “COVID smell” describe it as: 

• Raw sewage
• Rancid
• Sweet, sickly, and sour

Other reports describe it as smelling like rotten eggs or old trash.

Parosmia can make it very hard to enjoy food and drink because the smells can cause nausea and revulsion. Some people even report being disgusted by their own body odor or the smell of their spouse and children. 

Parosmia can cause problems with eating, weight loss, social isolation, depression, and anxiety. 

Losing taste and smell with COVID

At the beginning of the pandemic, loss of smell (anosmia) was such a common and unique symptom that some countries used smell tests to screen for COVID infection. 

And because taste and smell are so closely linked, most people who experience trouble with their sense of smell also lose their ability to taste. 

Luckily, complete loss of taste and smell doesn’t typically last long with a COVID infection. Most people who lose their sense of taste and smell due to COVID get it back within a few weeks. 

But anosmia is different from parosmia. People with parosmia can still smell, but their sense of smell is different. And this distorted sense of smell tends to develop as a person recovers from loss of smell. 

How does COVID infection cause parosmia?

Scientists are still trying to understand how this works. 

Changes in your ability to smell can happen with many viral infections, such as the common cold. Most people can relate to losing their sense of smell and taste while they have a stuffy nose. 

But with COVID, loss of smell and parosmia can happen without congestion. So if a stuffy nose isn’t causing changes in smell with a COVID infection, then what is? 

Researchers looking at the nerve pathways between the nose and the brain (the olfactory system) have some ideas. The most likely cause of smell changes during and after COVID infection is damage to the nerves responsible for smell. These researchers have found that the COVID virus can damage the cells in the nose responsible for smelling. This damage happens even if the virus does not directly infect the cells. This is what leads to the loss of smell early on in a COVID infection. 

There’s also evidence that the COVID virus damages cells that support the smelling nerves. Researchers think this may explain how the COVID virus can affect smell over several months, long after recovery from COVID. 

And the COVID virus may have further-reaching effects, too. COVID seems to affect the structure of the smell center itself. This may explain how smell changes can last longer in some people. 

In parosmia, it’s possible that as the smell pathways start to work again, nerves may start regenerating abnormally. And this may cause distorted and phantom smells. 

It’s still early days when it comes to understanding the long-lasting effects of COVID on the body — including the cells and nerves responsible for smell.  

How long does parosmia last after COVID infection?

Most people who experience changes in smell with COVID have a complete or partial recovery within a few weeks from the start of the changes. Studies show that symptoms significantly lessen in about 9 in 10 people after 4 to 8 weeks. 

But that means many people continue to have issues with their sense of smell. Studies show that parosmia can last longer than 6 months for some people. Researchers are still trying to figure out exactly how long COVID-related parosmia can last.

If you’re still experiencing problems with your sense of smell months after COVID infection, you aren’t alone. And there are things you can do to manage the symptoms. 

What’s the treatment for parosmia?

Researchers are still looking for ways to treat parosmia due to COVID. Olfactory training seems to be the best way to improve your sense of smell, or to get rid of bad smells in your nose. 

Olfactory (smell) training

Olfactory training can help get rid of bad smells in your nose. And you can do it naturally, without any prescriptions. 

Olfactory training is a process where you repeatedly smell certain odors. And it’s proven to improve the sense of smell in people with smell problems after viral infections. 

You can do olfactory training at home over a period of several months. It takes time. But there aren’t any risks, and it has good results. 

Here’s how to get started with olfactory training:

• Get four scents. The most common scents are eucalyptus, citronella (lemon), eugenol (clove), and phenylethyl alcohol (rose). You can buy these scents as part of a scent-training kit. Or you can make your own by soaking cotton in essential oil and putting it inside a small, airtight jar. 
• Smell each scent two times per day. The best times are in the morning, before breakfast, and in the evening, before bed.
• Sniff each scent for 15 to 30 seconds. Focus while you’re smelling. Take short, gentle sniffs and try to focus on your memory of the smell. 
• It can take weeks to months to notice an improvement. Experts recommend doing this twice daily for 24 weeks. But some studies show that certain people need to continue practicing longer and with different scents. 

Drugs that treat parosmia 

There are no medications that treat parosmia specifically — though scientists have studied several. There’s some evidence that inhaled steroid sprays, intranasal corticosteroids, may help with the loss of smell. Doctors and scientists recommend using intranasal corticosteroids if loss of smell lasts longer than 2 weeks. 

A small study of 85 people suggests that gabapentin may help with parosmia symptoms. But more research is needed into this and other potential treatments. 

To speed up recovery, stick with olfactory training even if you take medications, too. 

Strategies to manage living with parosmia

Parosmia isn’t life-threatening, but it can affect day-to-day life. It can make eating and drinking difficult. It can affect relationships and social interactions, too. 

Your sense of smell is closely linked to the parts of the brain that process emotions and memory. So it can be distressing if you can’t pick up familiar scents anymore. 

Here are some ways to manage common side effects from changes in your ability to smell:

• Focus on food textures and temperatures. If you can’t smell, or if you only experience bad smells, it can be hard to eat as you normally would. Instead of focusing on flavor, try to mix foods of different textures or temperatures. 
• Put safety measures in place. Sense of smell is important for detecting harmful odors, like gas or smoke. Make sure your home smoke alarms and carbon monoxide detectors are working. And keep your space well ventilated while using cleaning products. Check sell-by dates to prevent eating spoiled food. 
• Seek out support groups or therapy. Problems with sense of smell are often linked with changes in mood and a higher risk of depression. Online support groups offer a way to talk with other people going through the same problem. You may benefit from therapy or medication to treat depression. Talk with your healthcare provider about problems with smell and mood — it’s an important issue that deserves attention. 

For more tips on how to manage living with an altered sense of smell, visit AbScent and Fifth Sense. These U.K.-based charities focus on helping people with smell disorders. The Smell Podcast explores stories, news, and current research on smell and taste disorders. The Smell and Taste Association of North America also provides resources, such as linking to the Monell Center, which aims to advance research on olfactory dysfunction.

The bottom line

Loss or changes in sense of smell or taste are unpleasant and affect many aspects of daily life. For most people with COVID-19 infection, this problem doesn’t last long. But some people can have long-lasting symptoms that really affect health and well-being. Olfactory training is the best treatment option available. You can do this yourself at home over several months. Over-the-counter medications, like inhaled steroids, can also help.