Anosmia (Loss of Sense of Smell)

What is anosmia?

Anosmia is when you can’t detect an odor, whether it comes from pies fresh from the oven or smelly socks piled in a corner. It’s usually a temporary side effect of a cold or sinus infection. Our sense of smell fades as we age, so people age 50 and older may have long-lasting anosmia. In some cases, anosmia may be a symptom of other, more serious medical issues like a traumatic brain injury (TBI).

How does my sense of smell work?

The process starts with substances that smell and give off tiny molecules. When you inhale, the molecules glide into your nose and land on a tiny patch of tissue high inside it.

The patch is home to specialized cells called olfactory sensory neurons. These cells have a direct connection to your brain. When scent-bearing molecules attach to them, the cells notify your brain, which identifies the smell. Your brain then lets you know if something smells good or bad.

What are the symptoms of anosmia?

You can lose your sense of smell suddenly or over time. Early on, you may notice familiar scents are different, like a favorite cologne that seems to smell less potent than it did before.

What causes anosmia?

Anosmia may be a side effect of many common medical issues, including conditions that block your nose or interfere with signals sent from your special scent cells to your brain.

Conditions that block your nose are:

• Nasal polyps.
• Common cold.
• Influenza (flu).
• Nasal congestion.
• Sinus infection (Sinusitis).
• Deviated septum.
• Hay fever or other allergies.
• COVID-19.

Conditions that affect receptors in your nose include:

• Alzheimer’s disease.
• Brain tumors.
• Multiple sclerosis (MS).
• High blood pressure (hypertension).
• Kallmann syndrome.
• Parkinson’s disease.
• Sjogren’s syndrome.

Other causes may include:

• Taking certain medications, such as antibiotics and antihistamines.
• Smoking.
• Having obesity (a BMI or body mass index of 30 or higher).
• Diabetes.
• Traumatic brain injury.

Rarely, people are born with anosmia, or congenital anosmia. That means they’ll never be able to detect odors. About 1,000 people in the United States have congenital anosmia.

What are the complications of anosmia?

There’s more to anosmia than not being able to enjoy sweet or savory scents. Complications may include:

• Food poisoning Lack of smell and taste puts you at risk of food poisoning because you can’t tell when foods have spoiled.
• Increased risk of being hurt by smoke or fire: Anosmia can keep you from realizing there’s smoke in your home or workplace.
• Increased risk of inhaling natural gas or harmful chemicals: Because you can’t smell, you may not realize you’re exposed to gas or chemicals.

How is anosmia diagnosed?

Otolaryngologists diagnose anosmia. They’ll ask you when you first noticed you can’t detect odors and if the issue developed over time or suddenly. They’ll look inside your nose and do an odor identification test.

Odor identification tests involve sniffing and identifying different substances and telling the difference between substances. Your provider will also check your ability to identify odors as they become increasingly faint because they dilute the substance making the smell.

Your provider may do imaging tests like magnetic resonance imaging (MRI) or computed tomography (CT) scan.

How is anosmia treated?

In most cases, treating the underlying condition improves your sense of smell. For example, if you have sinusitis, antibiotics can help clear up the infection. If certain medications affect your sense of smell, switching medications may help ease your anosmia symptoms. If something is blocking your nose, like a nasal polyp, or you have a deviated septum, you may need surgery.

Can anosmia be prevented?

You can’t always prevent anosmia because so many things can cause it. In general, protecting yourself from colds and other respiratory conditions may reduce your risk of losing your sense of smell.

Can anosmia be fixed?

Often, anosmia is a side effect of many common medical issues. You’ll be able to smell again once the underlying issue goes away. Rarely, people have congenital anosmia, for which there’s no known cure.

How do I take care of myself?

If you have anosmia, you can’t detect troubling odors like smoke in your house or workplace or spoiled food. But you can take precautions:

• Be sure to install smoke detectors and to change their batteries often.
• Don’t take a chance that food that looks OK is safe to eat. Take a minute to read food expiration dates.

When should I see my healthcare provider?

Anosmia related to colds, flus and infections usually goes away within a few days. Talk to a healthcare provider if your cold or flu clears up and you still can’t detect odors.

What questions should I ask my healthcare provider?

If you have anosmia, understanding your condition can put your mind at ease and help you make decisions regarding treatment. Here are a few questions you may want to ask your provider:

• Is my loss of smell due to a cold, flu or infection, or a more serious medical issue?
• Could any of my medications cause anosmia?
• Can you estimate when my senses of smell will come back?

Can you taste food and drink without having a sense of smell?

Yes, but tasting things won’t seem the same as it did before you had anosmia. Your tongue can detect sweet, sour, salty, bitter and umami flavors. But without your sense of smell, you wouldn’t be able to detect subtle differences between them.

What’s the difference between ageusia and anosmia?

Anosmia means you can’t detect odors. Ageusia means you can’t taste food or drink. You can have anosmia without having ageusia, but you can have both conditions, given the close connection between your sense of smell and taste.

What’s the connection between my sense of smell and my sense of taste?

Taste and smell are chemical senses that work together. When you can’t smell foods and drinks, it affects how they taste. Say you take a bite of warm cherry pie:

• That first bite releases molecules in your mouth and nose.
• Receptors in your nose and mouth react to the taste and smell of cherry pie and alert your brain.
• Your brain gathers up the messages about how the cherry pie smells and tastes and lets you know that cherry pie smells sweet. When you taste it, you know cherry pie has a tart fruit filling and a buttery crust.

What’s the difference between anosmia and parosmia?

If you have parosmia, your sense of smell is distorted. For example, you may smell a cherry pie, but your brain tells you that you’re smelling spoiled milk.

A note from Cleveland Clinic

Anosmia means you’ve lost your sense of smell. Often, it’s a side effect of common medical issues like colds, seasonal allergies or polyps in your nose. Your sense of smell usually comes back once the underlying issue goes away or you receive treatment. Sometimes anosmia doesn’t go away. That’s when you should talk to a healthcare provider because it may be a symptom of serious medical conditions like diabetes or a brain injury.