What causes a loss of taste?

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The most common taste disorder is phantom taste perception. A person with this disorder will have a strong, lingering taste in their mouth, even when it is empty. The taste is often unpleasant and may overpower the taste of other foods while they eat. The taste may also occur alongside a persistent burning sensation in the person’s mouth.

There are three types of phantom taste perception:

Ageusia

A complete loss of the sense of taste is called ageusia, which can make a person unable to detect any tastes. However, ageusia is rare. A 2016 study estimates that only 3% of people who experience a loss of the sense of taste have true ageusia.

Dysgeusia

Dysgeusia causes a persistent taste in the mouth that can mask other tastes and make all foods taste the same. People with dysgeusia often say that the taste has particular characteristics, describing it as:

• foul
• rancid
• sour
• salty
• metallic

Hypogeusia

Hypogeusia is the term for a partial loss of one type of taste. A person with hypogeusia may be unable to detect one of the key tastes:

• bitterness
• sourness
• saltiness
• sweetness
• umami, which is a pleasant, savory taste

Other causes

Possible causes of taste disorders and a loss of taste can include:

• upper respiratory infections, such as the common cold
• COVID-19
• sinus infections
• middle ear infections
• poor oral hygiene and dental problems, such as gingivitis
• exposure to some chemicals, such as insecticides
• surgeries on the mouth, throat, nose, or ear
• head injuries
• radiation therapy for cancer in this area of the body

Causes of smell disorders may include:

• aging
• smoking
• growths in the nasal cavities
• conditions that affect the nervous system, such as Alzheimer’s disease or Parkinson’s disease

Learn more about loss of taste and smell due to COVID-19 here.

Some medications may also affect a person’s ability to taste. These drugs can include:

• antibiotics
• antihistamines
• chemotherapy drugs
• proton pump inhibitors
• protein kinase inhibitors

Taste disorders are not uncommon. Before the pandemic, more than 200,000 people in the United States visited the doctor each year to report difficulty tasting or smelling. Some experts estimate that 5% of Americans described dysgeusia, and almost 1 in 5 Americans over 40 reported some alteration in their sense of taste.

Specialists called otolaryngologists can diagnose and treat both smell and taste disorders. These doctors specialize in disorders that affect the ear, nose, and throat and conditions relating to the head and neck.

The doctor may look for growths in the mouth or nose, check a person’s breathing, and search for other signs of infection. They will also review the individual’s medical history and ask about any drug use and possible exposure to toxic chemicals.

The doctor will also want to examine a person’s mouth and teeth to check for signs of disease and inflammation.

To help diagnose the loss of taste, the doctor might apply certain chemicals directly to the individual’s tongue or add them to a solution that they then swish in their mouth. A person’s response to these chemicals may help identify the affected aspect of taste.

It can take time to identify both the type of sensory loss that the individual is experiencing and the underlying condition, but a correct diagnosis is an important step toward proper treatment.

The underlying condition causing the lost sense of taste will determine the treatment options. In simple cases, such as those resulting from the common cold or flu, doctors will usually wait until the infection subsides. With most people, their sense of taste should return once the illness goes away. However, evidence suggests that smell and taste problems may persist following SARS-CoV-2 infection, particularly in cases of long COVID.

While research is still unclear, if a person experiences post-viral olfactory dysfunction or smell and taste problems after a viral infection, a doctor may consider using olfactory training and topical corticosteroids.

For those with bacterial infections, such as sinus or middle ear infections, doctors may recommend antibiotics.

Treatment for more serious issues, such as nervous system disorders or head injuries, will require an individualized treatment plan.

In many cases, a person can take small steps at home to help improve their sense of taste, including:

• quitting smoking
• improving dental hygiene by brushing, flossing, and using a medicated mouthwash daily
• using over-the-counter antihistamines or vaporizers to reduce inflammation in the nose

It may not always be possible to prevent a loss of taste, and some cases may be the result of underlying conditions that require medical treatment. However, people can try to reduce the risk of ageusia resulting from infections by trying the following tips:

• eating a healthy diet and maintaining hydration
• getting plenty of rest
• practicing good hand washing technique
• wearing a face covering in public
• managing stress

Ageusia is the medical term for a complete loss of taste. A partial or full loss of the sense of taste can occur for many reasons, such as problems in the mouth or nose. In many cases, the cause is temporary, such as an infection that inflames the nasal passages.

Treating the underlying condition should make the symptoms go away. Some underlying causes, such as chemical exposure, Alzheimer’s disease, and aging, may cause a permanent loss of taste. It is essential for a person to work closely with a doctor to identify and treat the underlying issue.