Parosmia

What is parosmia?

Parosmia is a condition that distorts your sense of smell. People with parosmia may be unable to experience the full range of scents in their environment. Or the odors they detect smell “wrong.” For instance, warm cookies from the oven — which smell sweet and delicious to most people — might smell unpleasant and rotten to people with parosmia.

You may hear people refer to this condition as anosmia. But anosmia refers to a total loss of sense of smell. Anosmia and parosmia are both common symptoms of COVID-19, along with dysgeusia (a distorted sense of taste) and ageusia (a total loss of sense of taste).

How common is parosmia?

Parosmia is a common condition, even more prevalent since the onset of COVID-19. In 2007, one study found that approximately 3.9% of adults experience parosmia at some point. A 2021 study — published over a year after the first COVID-19 case appeared in the U.S. — estimated that 40% to 75% of people with COVID-19 develop parosmia.

In addition, the average onset for parosmia in people with COVID-19 is three months after the initial infection. Parosmia is a common long COVID symptom.

What are the symptoms of parosmia?

Parosmia symptoms vary from person to person. Some cases are mild and short-lived. Others are severe and long lasting. In most cases, people start to notice parosmia symptoms after recovering from an infection.

People with parosmia might:

• Have trouble detecting certain scents in their environment.
• Smell a foul odor, particularly when food is present.
• Find previously pleasant scents overpowering and undesirable.

What causes parosmia?

There are several different conditions that can cause parosmia, including:

• COVID-19.
• Acute sinusitis.
• Head trauma.
• Nasal polyps.
• Common cold.
• Influenza (flu).
• Certain medications.
• Chronic dry mouth (xerostomia).
• Smoking.
• Chemical exposure.
• Cancer treatments.
• Temporal lobe seizures.
• Brain tumors (less common).

Is parosmia contagious?

While parosmia itself isn’t spreadable, the infections that cause it are contagious. To reduce your risk, be sure to distance yourself from anyone who’s sick and practice good hygiene habits.

How do you test for parosmia?

A healthcare provider, usually an otolaryngologist (ENT), will ask about your health history, including recent infections, current medications and lifestyle factors (such as smoking). Next, they’ll likely ask you to sniff different substances, and then describe the scent.

In some cases, your healthcare provider may request additional tests, including:

• Imaging tests, such as MRI or a sinus CT scan.
• A biopsy of sinus tissue.

These tests can help your provider determine the underlying cause of parosmia so they can recommend appropriate care.

How do I fix parosmia?

Parosmia treatment depends on the cause. While the vast majority of people eventually regain a partial or full sense of smell, a small number of people never do.

Removing potential triggers

If parosmia is the result of environmental factors — like smoking, medications or chemical exposure — your sense of smell will likely return once you remove those triggers. Be sure to consult your healthcare provider before stopping any medications.

Medication

In some cases, your provider may prescribe medication to ease parosmia symptoms. Research is ongoing, but studies suggest that these drugs may help restore your sense of smell:

• Phenytoin.
• Clonazepam.
• Topiramate.
• Valproic acid.

Olfactory training therapy

Also called “smell training,” this approach involves sniffing various substances for several seconds at a time. You repeat the process twice a day for several months. Your healthcare provider can let you know if this is an option for you.

Parosmia surgery

If parosmia is a symptom of nasal polyps or a brain tumor, then your healthcare provider may recommend surgery.

Sometimes, a surgeon can remove the damaged sensory receptors in your nose to restore your sense of smell. But this is a complex procedure and the risks often outweigh the benefits. Explore your options thoroughly before deciding on treatment.

Can I prevent parosmia?

Because parosmia is often the result of trauma, viruses and other uncontrollable factors, it’s not possible to prevent it completely. But if parosmia is due to environmental factors, like smoking or chemical exposure, removing those triggers should reduce or eliminate your symptoms.

To reduce your risk of bacterial- and viral-related parosmia, wash your hands frequently and follow all U.S. Centers for Disease Control and Prevention (CDC) recommendations and guidelines.

How long does parosmia last after COVID?

Parosmia is one of the most common long COVID symptoms. According to one research study, people with COVID-related parosmia start to regain their sense of smell approximately 14 to 16 months after infection.

Can parosmia be permanent?

Yes. In some cases, parosmia is permanent. But full recovery is common. Ask your healthcare provider for details about your situation.

Current research suggests that COVID-related parosmia is only temporary, though symptoms can last for a year or longer.

When should I see my healthcare provider?

Anytime you notice a distorted or absent sense of smell, you should schedule an appointment with a healthcare provider. They can determine why you have parosmia and whether you need treatment for an underlying condition.

A note from Cleveland Clinic

Parosmia is a distorted sense of smell. Things that used to smell pleasant now smell foul to people with parosmia. People get parosmia for many reasons, including infections, medications and trauma. You can’t always prevent it, but in most cases, it’s temporary. Because parosmia is a symptom of so many conditions, it’s important to get an evaluation from a healthcare provider.