Most of us take our sense of smell for granted. But have you ever thought about what it would be like to not be able to smell something? The complete loss of smell is called anosmia (an-OHZ-me-uh). Without your sense of smell, food tastes different, you can't smell the scent of a flower, and you could find yourself in a dangerous situation, unknowingly. For example, without the ability to detect odors, you wouldn't smell a gas leak, smoke from a fire, or sour milk.
Taste and smell disorders send hundreds of thousands of Americans to the doctor each year. Fortunately, for most people, anosmia is a temporary nuisance caused by a severely stuffy nose from a cold. Once the cold runs its course, a person's sense of smell returns. It can also be a symptom of COVID-19.
But for some people, including many elderly, the loss of a sense of smell may persist. In addition, anosmia can be a sign of a more serious medical condition. Any ongoing problems with smell should be checked out by a doctor.
The Basics of Smell
A person's sense of smell is driven by certain processes. First, a molecule released from a substance (such as fragrance from a flower) must stimulate special nerve cells (called olfactory cells) found high up in the nose. These nerve cells then send information to the brain, where the specific smell is identified. Anything that interferes with these processes, such as nasal congestion, nasal blockage, or damage to the nerve cells themselves, can lead to loss of smell.
The ability to smell also affects our ability to taste. Without the sense of smell, our taste buds can only detect a few flavors, and this can affect your quality of life.
Nasal congestion from a cold, allergy, sinus infection, or poor air quality is the most common cause of anosmia. Other anosmia causes include:
- Nasal polyps -- small noncancerous growths in the nose and sinuses that block the nasal passage.
- Injury to the nose and smell nerves from surgery or head trauma.
- Exposure to toxic chemicals, such as pesticides or solvents.
- Certain medications, including antibiotics, antidepressants, anti-inflammatory medication, heart medications, and others.
- Cocaine abuse.
- Old age. Like vision and hearing, your sense of smell can become weaker as you age. In fact, one's sense of smell is most keen between the ages of 30 and 60 and begins to decline after age 60.
- Certain medical conditions, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, nutritional deficiencies, congenital conditions, and hormonal disturbances.
- Radiation treatment of head and neck cancers.
The obvious sign of anosmia is a loss of smell. Some people with anosmia notice a change in the way things smell. For example, familiar things begin to lack odor.
If you experience a loss of smell that you can't attribute to a cold or allergy or which doesn't get better after a week or two, tell your doctor. Your doctor can take a look inside your nose with a special instrument to see if a polyp or growth is impairing your ability to smell or if an infection is present.
Further testing by a doctor who specializes in nose and sinus problems -- an ear, nose, and throat doctor (ENT, or an otolaryngologist) -- may be needed to determine the cause of anosmia. A CT scan may be necessary so that the doctor can get a better look of the area.
If nasal congestion from a cold or allergy is the cause of anosmia, treatment is usually not needed, and the problem will get better on its own. Short-term use of over-the-counter decongestants may open up your nasal passages so that you can breathe easier. However, if the congestion gets worse or does not go away after a few days, see your doctor. You may have an infection and need antibiotics, or another medical condition may be to blame.
If a polyp or growth is present, surgery may be needed to remove the obstruction and regain your sense of smell.
If you suspect a medication is affecting your sense of smell, talk to your doctor and see if there are other treatment options available that won't affect your ability to smell. However, never stop taking a medication without first talking with your doctor.
Sometimes a person will regain their sense of smell spontaneously. Unfortunately, anosmia is not always treatable, especially if age is the cause. But there are steps you can take to make living with the inability to smell more pleasant and safer. For example, put fire detectors and smoke alarms in your home and office and take extra care with leftovers. If you have any doubt about a food's safety, don't eat it.
If you smoke, quit. Smoking can dull your senses, including your sense of smell.