What Can Cause a Loss of Taste and Smell?

Several viruses and health conditions, including COVID-19, could be the reason for your loss of taste and smell.

A bouquet of flowers. A home-cooked meal. Milk that’s past its best-by date. Our senses of taste and smell help us to detect and catalog a wide spectrum of flavors and scents. Both can also serve to tell us when something’s not safe to eat. And, interestingly, what we perceive as a disruption in our ability to taste may often be rooted in issues related to our sense of smell.

Here Kevin Hur, MD, a rhinology specialist at Keck Medicine of USC, outlines 4 common reasons that may cause you to lose your sense of taste or smell.

1. Viral infections, like the flu, colds and COVID-19

If you’ve had a cold, you may be all too familiar with a stuffy nose that makes it hard to smell. In fact, both the common cold and influenza can cause temporary anosmia, or a complete inability to detect odors. Scientists have also identified a loss of taste and smell among the symptoms associated with COVID-19.

“Viruses can damage the cells that detect odors and cause swelling in your nose, which limits airflow to smell receptors,” says Dr. Hur, an assistant professor of clinical otolaryngology – head and neck surgery at the Keck School of Medicine of USC.

When smell is lost, often taste is, too. When you chew food, the released aromas reach your nose and activate your sense of smell. If your nose is stuffed or blocked by a cold or the flu, the odors can’t reach the sensory cells in your nose, and you lose much of the enjoyment of flavor. Foods taste bland and lose nuance.

2. Neurological conditions

”Some neurodegenerative conditions that affect the nervous system, such as Alzheimer’s disease, Parkinson’s disease and multiple sclerosis (MS), may affect areas of the brain responsible for processing odors that affect a patient’s smell and taste,” says Dr Hur.

It’s important to note that just because you’re experiencing a loss of smell, it doesn’t mean you will develop Parkinson’s. But reduced sense of smell, or hyposmia, is often an early sign of the disease.

3. Nasal polyps

If you’re prone to frequent sinus infections, you may develop nasal polyps, or benign growths in the nose that may affect smell, due to inflammation of the lining of the nose that can prevent odors from reaching smell nerves.

“Nasal polyps eventually can grow to a size that prevents airflow to the cells that detect odors,” Dr. Hur says.

Treatment may include topical medications, such as steroid sprays and nasal saline rinses, that shrink the polyps. In some cases, surgery also may be performed.

Once inflammation is under control, a full sense of smell may return.

4. Age

According to the National Institutes of Health, up to 1 in 4 Americans over the age of 40 may experience changes in their sense of smell; that number increases to nearly 1 in 3 for people over the age of 80. When it comes to taste, 1 in 5 Americans may experience changes after they turn 40.

As we age, several factors can contribute to a loss of taste and smell, including dental issues, dry mouth, certain medications, alcohol consumption and smoking. In addition, less mucus production in the nose, a loss of nerve endings and changes in the taste buds can occur as we age, affecting smell and taste.

If you’re experiencing a loss of taste and smell, talking to your primary care physician or visiting an otolaryngologist, a doctor who specializes in the conditions of the ear, nose and throat, may help you pinpoint what’s causing these changes in your senses.

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