Parosmia and COVID: How Long Changes in Smell Last, Plus Treatment Options

Your sense of smell is deeply tied to memory. Just a whiff of a familiar scent can bring memories of happy times. But for some, those smells no longer bring back memories. Instead, once-wonderful smells can cause them to gag. This condition, known as parosmia, is a change or distortion of normal smell. It’s one of the types of smell changes that people experience after a COVID-19 illness and other medical conditions. 

Changes in smell (and taste) are very common during and after COVID. 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. Others can smell bad smells that aren’t actually there.

In most cases, changes in smell go away within a few weeks without treatment. But for some, the symptoms last much longer. And when smell changes drag on, it can make daily life distressing. 

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

What is parosmia and what are its symptoms?

Parosmia is a medical condition that causes a distorted sense of smell. Symptoms of parosmia include:

• Smell distortion: Things that once smelled good can now smell horrible.

• Trouble identifying smells: Difficulty distinguishing or identifying certain smells. 

• Phantosmia: Detecting smells that aren’t there, like smoke.

• Altered taste: Foods may taste bad or different than normal.

Parosmia is a type of olfactory dysfunction, a group of conditions that affect the sense of smell. People with parosmia often experience other types of olfactory dysfunction at the same time. The most common changes include:

• Anosmia: A total loss of smell.

• Hyposmia: A partial loss of smell.

Many people develop olfactory dysfunction when they’re sick with COVID. Anosmia and hyposmia tend to happen early in the infection. But parosmia symptoms can start as early as 1 week after the start of COVID symptoms or as late as weeks or months after the initial infection. 

EXPERT PICKS: WHAT TO READ NEXT

• COVID-19 isn’t the only thing that causes loss of smell. Take a look at other conditions that cause parosmia. 

• What’s it like to live with parosmia? One person shares their experience with GoodRx.

• Loss of smell can affect nutrition. Here’s how to eat when you can’t taste.

Parosmia symptoms can last for months, even after full recovery from a COVID illness.

What does COVID parosmia feel like?

People with COVID-related parosmia describe changes to their everyday smells. Things that once smelled good or neutral now smell like: 

• Raw sewage

• Something rancid

• Sweet, sickly, or sour

• Rotten eggs

• Trash

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

These unpleasant experiences can lead to:

• Trouble eating

• Weight loss and poor nutrition

• Social isolation

• Mood changes, including depression and anxiety

Anosmia, hyposmia, and COVID: Loss of taste and smell

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. 

Because taste and smell are so closely linked, most people who experienced trouble with their sense of smell also had a loss of taste. 

Luckily, the complete loss of taste and smell doesn’t usually last long with a COVID infection. Most people regain their senses within a few weeks. 

But some people can develop parosmia as they recover from anosmia and hyposmia. So, when their sense of smell returns, it may be distorted. 

How does COVID infection cause parosmia?

Scientists are still trying to understand how the COVID virus triggers olfactory dysfunction like parosmia, anosmia, and hyposmia.

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

But with COVID, olfactory dysfunction can happen even without congestion. So if a stuffy nose isn’t causing changes in smell during a COVID infection, 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. Studies show that the COVID virus can damage the cells in your nose responsible for smelling. This damage happens even if the virus doesn’t directly infect the cells. This damage explains the loss of smell early in a COVID infection. 

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

And the COVID virus may have even further-reaching effects. The virus seems to affect the structure of the brain’s smell center. This may explain how smell changes can last longer in some people. 

In cases of 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. 

How long does parosmia last?

Parosmia can last for weeks to months, depending on what triggered the changes in smell. Most people who experience smell changes due to COVID have a complete or partial recovery within a few weeks. Studies show that symptoms significantly improve in about 9 out of 10 people within 4 to 8 weeks. 

What are other causes of parosmia?

Many other medical conditions can cause parosmia, including:

• Common cold viruses

• Influenza virus

• Seasonal allergies

• Nasal polyps

• Smoking and vape products

• Head trauma

• Parkinson’s disease

• Alzheimer’s disease

• Vitamin deficiencies

• Environmental exposures like solvents, metal dust, and fumes.

Certain medications can also trigger parasomnias. These include:

• Allergy medications: Loratadine and fluticasone 

• Antibiotics: Amoxicillin and azithromycin

• Blood pressure medications: Lisinopril and metoprolol

• Cholesterol medications: Atorvastatin and pravastatin

• Reflux medications: Omeprazole and ranitidine

What’s the treatment for parosmia?

There’s no cure for parosmia, but there are treatments that may help. Olfactory training seems to be the best way to improve your sense of smell or get rid of bad smells in your nose. 

Olfactory (smell) training

Olfactory training can help get rid of bad smells in your nose. And it can be done naturally, without prescriptions. 

Olfactory training involves repeatedly smelling certain odors. This process is proven to improve the sense of smell in people with smell problems after viral infections. 

You can do olfactory training at home over 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:

1. 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 balls in essential oils and putting them inside small, airtight jars. 

2. Smell each scent twice a day: The best times are in the morning, before breakfast, and in the evening, before bed.

3. Sniff each scent for 15-30 seconds: Focus while you’re smelling. Take short, gentle sniffs and try to focus on your memory of the smell. 

4. Be patient: 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 may need to continue practicing longer and with different scents. 

Medications 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, depending on what caused the parosmia.

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

To speed up recovery, stick with olfactory training, even if you’re also taking medications. 

How 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. And it can affect relationships and social interactions.

Your sense of smell is closely linked to the parts of your 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 mixing 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’s smoke alarms and carbon monoxide detectors are working. Also, 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 the sense of smell are often linked to mood changes and a higher risk of depression. Online support groups offer a way to talk with other people going through the same problem. You may also benefit from therapy or medication to treat depression. Talk with a healthcare professional about any issues 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, check out the following resources:

• AbScent and Fifth Sense, which are U.K.-based charities that focus on helping people with smell disorders. 

• The Smell Podcast, a podcast that explores stories, news, and current research on smell and taste disorders. 

• The Smell and Taste Association of North America, which provides resources and links to other helpful resources.

• Monell Center, which aims to advance research on olfactory dysfunction.

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Written by:

Christine Giordano, MD

Christine Giordano, MD, is board-certified in general internal medicine. She received her medical degree from Rutgers New Jersey Medical School and completed residency at Thomas Jefferson University.

Edited by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

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