Overview: What does the loss of taste and smell feel like?
Taste and smell are closely related senses, but they are very different. Taste buds on the tongue sense what we taste—sweet, sour, salty, bitter, and savory—and the brain processes these sensations in one region. Smell receptors in the nose detect what we smell, and another part of the brain processes these sensations. The sense of smell can be affected by some medical conditions. Other medical conditions can affect the sense of taste. Most of what we believe we “taste” is what we smell, so when people have a reduced sense of smell (hyposmia) or a complete loss of smell (anosmia), they typically feel they’ve lost both taste and smell. However, that’s not true. Only 5% of people who say they’ve lost their taste and smell have a taste disorder—all the rest only have smell disorders. About 1 in 20 people have a reduced sense of taste (hypogeusia) or completely lose their taste (ageusia). In those cases, they can still recognize flavors, like steak, but don’t taste sugar or salt. It’s less common for people to lose both their taste and smell.
What causes the loss of taste and smell?
Only a few medical conditions cause the loss of taste and smell. The most common cause of loss of taste and smell is age. As people age, both taste and smell become less sensitive. Other loss of taste and smell causes include:
Upper respiratory infections, such as cold, flu, or COVID-19
Allergic rhinitis
Dental problems, such as gum disease (gingivitis) or tooth decay
Dietary deficiencies or malnutrition
Head or brain injury
Neurological disorders, including Alzheimer’s disease, multiple sclerosis, Parkinson’s disease, and Bell’s palsy
Diabetes
Autoimmune disorders, such as Sjogren syndrome
Head or neck surgery
Radiation therapy
Genetics
Some medications, such as antibiotics, chemotherapy, statins, antihistamines, high blood pressure medications, and thyroid hormones
Smoking
Chemical exposure
Should I be worried about the loss of taste and smell?
The loss of taste and smell is not health-threatening, but it could be a sign of a serious medical condition, such as a COVID-19 infection. If both taste and smell decrease suddenly, persist for several weeks, or are accompanied by other symptoms, contact a healthcare provider for medical advice. Emergency medical care is needed if there are severe symptoms, such as mental changes, difficulty breathing, or a high fever.
How is the cause of the loss of taste and smell diagnosed?
Diagnosing the cause of loss of taste and smell is a complex puzzle to solve. Often, there’s just one cause, but there’s a possibility that two things are going wrong, one affecting the sense of smell and another affecting the sense of taste. Although a primary care provider may start the diagnosis process, a dentist or a specialist in ear, nose, and throat disorders, called an otolaryngologist, may be needed.
Diagnosis will require a complete physical exam, an exam of the head and neck, and an exam of the oral cavity. An ear, nose, and throat (ENT) specialist may look at the nasal passages for problems in the nasal cavity, such as nasal polyps. This will be done with a procedure called a nasal endoscopy, which is performed with a camera attached to a flexible tube. A dentist may have to follow up on an oral exam with a complete dental exam.
In addition to the many tests that may be required, people may undergo taste or smell tests. These tests aren’t required, but they confirm and quantify the extent to which taste and smell have been compromised.
Taste tests are usually just that. People taste solutions or apply paper strips or cotton swabs to various parts of the tongue to identify the taste. A clinician or the patient will fill out a rating questionnaire to determine how much of a substance is required to produce a taste response, the intensity of the sensation, and whether it’s enjoyable or awful. Using cotton swabs, a clinician can then determine what parts of the tongue are affected.
Smell tests accomplish the same goals. By having the patient smell various substances, the clinician can determine the minimal amount of smells that must be identified, the intensity of smells, and whether those smells are experienced as good or bad.
Electrodes can measure taste and smell in less common cases. Other tests may include blood tests, urine tests, or medical imaging of the head or neck, such as a CT scan, MRI, or PET scan.
RELATED: Should I see an ENT or allergist?
Is the loss of taste and smell contagious?
If the loss of taste and smell is associated with a viral infection, such as a cold, flu, or COVID-19, other people can catch that infection. The loss of taste and smell, however, is not contagious. In some cases, the infection will resolve, but the loss of taste and smell will linger for days, weeks, or even months afterward. Once the original infection is gone, there’s no danger of contagion.
How long does the loss of taste and smell last?
The loss of taste and smell will last for as long as the underlying condition is causing it, sometimes longer. The loss of taste and smell is usually a temporary health problem lasting days or weeks. Some causes may result in a chronic or permanent reduction in taste and smell, particularly if nerves or the central nervous system are damaged. In those cases, smell retraining and other therapies can help improve smell, but not taste.
How to stop the loss of taste and smell
Healthcare professionals don’t treat loss of taste, but they can treat loss of smell in a limited way through smell retraining, occupational therapy, and some medications that may improve olfactory function, such as corticosteroids and theophylline.
The only way health professionals treat the combined loss of taste and smell is by treating the underlying cause:
Getting rid of the loss of taste and smell when it’s due to smoking is not complicated—most people will see improvements in taste and smell when they quit smoking and avoid secondhand smoke
Eliminating exposure to environmental causes, such as toxins or pollution, is usually enough to improve taste and smell
The sense of taste and smell will usually return when the body fights off the infection that’s causing it, but the loss of taste and smell may linger for days, weeks, or longer
Avoiding allergens and using allergy medications can help prevent and treat allergic reactions
Switching to different types of medications may help with the loss of taste if a medication is the cause
Dietary deficiencies are treated with dietary changes and supplements
Dental problems are treated with oral surgery, prescription medications, and adopting good oral hygiene practices
Dry mouth can be treated by drinking fluids, using humidifiers, breathing steam, or using artificial saliva
Other medical conditions that cause the loss of taste and smell may require prescription medications or surgery
Living with the loss of taste and smell
Living with the loss of taste and smell is challenging. Much of our enjoyment in life comes from tasting and smelling foods and drinks and experiencing pleasant smells around us. The first thing people can do is try smell retraining, a proven therapy that can be done at home. Smell retraining increases one’s perceptions of the sense of smell and involves sniffing the same four scents from essential oils twice per day. The nature of these essential oils is not considered important, but in the original research, the investigators used eucalyptus, rose, citronella (lemon), and eugenol (cloves). Other remedies involve drinking fluids to keep the oral cavity moist or trying various foods to find the most flavorful and enjoyable.
RELATED: How to regain taste and smell after coronavirus
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