Loss of Taste and Smell
Your sense of smell and taste work together to help you enjoy foods and drinks. When you lose your sense of smell — due to age, a health problem or a medicine — foods can seem tasteless or bland. Losing taste and smell can be an early symptom of a COVID-19 infection. A complete loss of smell (anosmia) or loss of taste (ageusia) is rare.
How does the sense of smell work?
Molecules in the air activate your sense of smell (olfaction). These molecules enter your nose and mouth. They attach to receptor cells in nasal mucus membranes. The receptors send messages to your brain that tell you when something has a pleasant or foul aroma.
How does the sense of taste work?
Molecules that dissolve in liquids activate your sense of taste (gustation). Tastebuds on your tongue have receptors that respond to substances. You also have receptors on the roof of your mouth and back of your throat. The receptors send messages to your brain that tell you when foods or drinks are sweet, salty, sour, bitter or savory (umami).
What’s the link between taste and smell?
Taste and smell are chemical senses that work together. When you can’t smell foods and drinks, it affects how they taste. These combined senses are how you tell the difference between coffee and tea or blueberries and raspberries.
Here’s how these senses work together:
- The act of eating or drinking releases molecules.
- These molecules stimulate receptors in your nose and mouth.
- The receptors send messages to your brain.
- Your brain combines this information to help you recognize and enjoy complex flavors.
What is loss of smell?
Many conditions can affect your olfactory senses (sense of smell). You may have hyposmia (partial loss of smell) or anosmia (complete loss of smell).
Your ability to smell gets weaker after age 50. Nasal membranes become thinner and drier, and nerves don’t work as well.
What is loss of taste?
It’s uncommon to lose your ability to taste. Most often, a loss of smell makes foods taste bland.
The medical term for a complete inability to taste is ageusia (uh-gyou-zee-uh). More people have hypogeusia, which means foods and drinks don’t taste as flavorful as they should.
Taste buds become less sensitive after age 50. Foods may taste bitter even when they’re not. You may have a harder time telling when things are sweet or salty too.
How common is loss of smell or taste?
Close to a quarter-million Americans see their doctor every year for smell or taste problems. Experts estimate that more than 1 in 10 Americans may have a smell or taste disorder, but few seek help.
What causes loss of smell and taste?
Aging often contributes to a diminished ability to smell and taste. Other causes include:
- Brain injuries.
- Cancer treatments like radiation therapy.
- Dry mouth from Sjogren’s syndrome or other conditions.
- Exposure to chemicals.
- Gum disease (gingivitis) and other dental problems.
- Medications, such as antibiotics and antidepressants.
- Nasal polyps, sinus infections and sinonasal tumors.
- Neurological disorders like Alzheimer’s disease and Parkinson’s disease.
- Viral respiratory infections, including the cold, flu and COVID-19 virus.
- Thyroid problems like hypothyroidism (underactive thyroid).
How do illnesses like COVID-19 cause loss of smell or taste?
Some viruses damage olfactory sensory neurons, nerves that help you smell. It may take months to recover from this damage. And being sick can make it hard to smell if your nose is stuffed up. With COVID-19, more than 8 in 10 people may briefly lose their sense of smell. Along with it, they lose their ability to taste. Researchers are still trying to determine how and why the COVID-19 virus affects smell and taste. One study suggests the virus doesn’t directly damage olfactory sensory neurons. Instead, it may affect cells that support these neurons. Once the infection goes away, the olfactory nerve starts working properly again. Most people regain these senses within 60 days of recovering from COVID-19.
Can loss of smell or taste cause complications?
When your sense of smell or taste declines, meals lose their appeal. Eating too little can put you at risk for malnutrition, dehydration and unhealthy weight loss. To give food flavor, you may add too much sugar or salt. These additions can increase your risk of diabetes and high blood pressure.
Lack of smell and taste puts you at risk for food poisoning because you can’t tell when foods have spoiled. You also may not be able to smell fire and smoke, natural gas or harmful chemicals in your home or surroundings.
A lack of appetite combined with an inability to smell pleasurable scents may contribute to depression.
Care and Treatment
How is loss of smell or taste diagnosed?
Your healthcare provider will conduct a physical exam and ask about other symptoms like nasal congestion (a stuffy nose). You should tell your healthcare provider about any recent respiratory infections, head injuries or other problems. They also need a complete list of medications and supplements you take.
You may see an otolaryngologist (an ear, nose and throat or ENT doctor). This healthcare provider may give you a smell test. You sniff and identify different scents. Or they may have you sniff a chemical. Your doctor dilutes the substance until you can no longer smell it.
For a taste test, you may sample substances applied directly to your tongue. Or you may sip different flavored liquids and spit them out. Your healthcare provider may increase the strength of the solutions or ask you to note differences between different flavors. Depending on your symptoms, your healthcare provider may order imaging tests of your head and brain. A CT scan or MRI can identify cysts, tumors and other problems.
How do doctors treat a loss of smell or taste?
When possible, your healthcare provider will treat the problem that’s affecting your senses. If you’re taking a supplement or medication that can affect your senses, you may need to change it to see if that heightens them. Unfortunately, people don’t always get their sense of smell or taste back.
You can take these steps to make meals more pleasurable:
- Add small amounts of strong cheese, bacon or toasted nuts to dishes.
- Use aromatic herbs, seasonings and spices (not salt) to boost flavor.
- Serve foods that have different textures and colors.
- Skip dishes like casseroles, which combine a lot of foods, because the mixture dilutes flavors.
A note from Cleveland Clinic
You should tell your healthcare provider if you experience a loss of smell or taste. While it can be normal, especially as you get older, these symptoms can sometimes indicate a health problem or a medication side effect. Treating a health condition or changing medications may help you regain some or all of your lost sense of smell or taste.
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