Many possible causes may lead to a loss of taste, including new medications, dental problems, cold or flu, and COVID-19. The type of treatment will depend on the underlying cause of a lost sense of taste.

Taste is a complex sense involving many organs and tissues, such as the tongue, roof of the mouth, throat, and nose. This is why smell can affect taste.

The medical term for a complete loss of taste is ageusia, while loss of smell is anosmia. A lost sense of taste may refer to a partial or total loss of taste. A loss or alteration in taste can occur due to many different conditions, such as those that affect the taste organs, nervous system, or infection.

This article discusses the possible reasons a person may experience a lost sense of taste and how doctors diagnose and treat the underlying issues.

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Taste disorders are not uncommon – more than 200,000 people in the United States visit 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.

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

Ageusia is a rare condition in which a person has a complete loss of taste function. Total ageusia occurs in approximately 1 to 2 people in every 1,000 and is more common as people age. In many cases people will experience a partial loss of taste rather than total.

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

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

Underlying causes

Taste disorders are typically due to soft tissue, and nerve damage to the tongue. Possible causes of taste disorders and a loss of taste can include:

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

Smell

Impairments to a person’s sense of smell will also affect their ability to taste. Factors that may impact a person’s smell include:

  • aging
  • smoking
  • growths in the nasal cavities
  • conditions that affect the nervous system, such as Alzheimer’s disease or Parkinson’s disease
  • physical trauma
  • infections
  • congenital anosmia – an inability to smell from birth

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. Imaging tests are also a consideration if loss of taste is thought to be secondary to loss of smell.

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. Most people’s sense of taste should return once the illness goes away.

However, respiratory infections can have longer-lasting symptoms. For example, 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. Plasma-rich protein therapy is also an emerging therapy option.

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 in some cases, it 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. A person needs to work closely with a doctor to identify and treat the underlying issue.