Taste and Smell Disorders
Taste and smell both contribute to your enjoyment of life. They also serve as warning systems. Taste alerts you to a food's nutritional value (too salty, too sweet, too rich), while smell alerts you to danger signals such as a natural gas leak.
Taste and smell are “chemical senses." Taste is activated when your taste buds respond to substances dissolved in your saliva. Smell occurs when a substance stimulates the olfactory nerve in your nose.
The loss of taste or smell can result from a variety of conditions. COVID-19 certainly brought the conditions to light as it can be a symptom of the virus. However, there are other disorders that can cause those symptoms as well.
The most common taste and smell disorders are (ordered most common to least common):
- Anosmia: total loss of smell
- Hyposmia: reduced ability to smell
- Hypogeusia: reduced ability to taste
- Ageusia: total loss of taste
Causes of Taste and Smell Disorders
While some individuals are born unable to taste or smell, for most people these symptoms are signs of other health problems. Possible causes include:
- Nervous system disease
- Illness (allergies or sinus/respiratory infection)
- Nasal polyps
- Head injuries
- Exposure to certain chemicals
- High blood pressure
- Poor nutrition
- Cocaine taken through the nose
- Exposure to radiation therapy for head or neck cancer
The loss of taste or smell affects about 2 million Americans each year, and it becomes more common as we age. One study indicated that 25% of men ages 60-69 had a smell disorder, while 11 percent of women those ages reported a problem.
Symptoms of Taste and Smell Disorders
Those affected by loss of taste and smell experience symptoms on a spectrum, from reduced ability to taste or smell to total loss of taste and smell. Some people may experience the loss of all types of tastes/smells, while others may only lose specific flavors (sweet, sour, bitter or salty).
Individuals may also find that smells they typically enjoy become extremely unpleasant.
Diagnosing Taste and Smell Disorders
When you visit an ear, nose and throat (ENT) doctor (also known as an otolaryngologist) to discuss a taste and smell disorder, they will first conduct a physical exam to make sure the loss is not simply caused by conditions in the nasal passageway.
There are two categories of tests used to diagnose a taste and smell disorder.
Threshold tests use solutions of various strengths to test how strong a sweet, sour, bitter or salty flavor must be for an individual to be able to recognize it.
Odor tests present the patient with a set of smells that they are asked to identify. Diagnosis is dependent on successfully (or unsuccessfully) identifying the smells.
Treatment of Taste and Smell Disorders
The treatment for taste and smell disorders depends on the condition.
For example, allergy and sinus disease management would be recommended for those individuals with these conditions. Individuals will often regain taste and smell after appropriate medical management.
If the loss of taste and smell is due to medicine, the physician may choose to adjust the dosage or change the prescription entirely.
Smell rehabilitation or training in conjunction with counseling can be helpful for some individuals.
When to See a Doctor about Loss of Taste or Smell
If you have reduced or complete loss of taste and smell, please contact your primary care doctor. You may be referred to an ENT specialist for a more comprehensive evaluation.