Loss of Smell and Taste: Common Causes, Safety Tips and When to Be Seen

What it involves

MedlinePlus defines impaired smell as the partial or total loss, or abnormal perception, of the sense of smell, and impaired taste as a problem that ranges from distorted taste to complete loss. It adds that much of what is perceived as taste actually comes from smell.

Who this is for

• Patients whose sense of smell has dimmed or disappeared and has not come back after a cold
• Patients whose food tastes bland, metallic or wrong
• Patients with a stuffy nose, allergies or sinus pressure who also notice flatter flavors
• Patients who started a new medicine or had a head injury and then noticed the change

What to expect

• Questions about when the problem began, whether all odors or only some are affected and whether taste has changed too
• A look in and around the nose and mouth and a review of your medicines and any cold or allergy symptoms
• Blood work if a vitamin deficiency or another condition is suspected, since the practice lists blood work among its services
• A plan that treats the likely cause or refers you to an ear, nose and throat specialist

How smell and taste work together

The tongue detects sweet, salty, sour, savory and bitter tastes, but MedlinePlus says flavor is a combination of taste and smell, so people who lose their sense of smell often feel they have lost their taste as well. Most can still tell salty, sweet, sour and bitter apart, but they may not be able to distinguish other flavors. Some spices, such as pepper, act on the nerves of the face, so you may feel them rather than smell them. That is why a stuffy nose makes meals seem so dull.

The usual causes of lost smell

Temporary loss of smell is common with colds and nasal allergies, according to MedlinePlus, and it may occur after a viral illness. It lists blockage from nasal polyps or a deviated septum, infections of the nose, throat or sinuses, allergies, head injury, endocrine disorders, nutritional deficiencies, radiation to the head or face and nasal or sinus surgery. Long-term use of nasal decongestants and certain other medicines can also dull smell. The seasonal allergies guide and the sinus infection guide cover two of the most common triggers.

Causes of altered taste

For taste, MedlinePlus lists the common cold, flu and other viral infections, nasal infection, polyps and sinusitis, strep throat, salivary gland infections, head trauma, ear or sinus surgery, heavy smoking, mouth dryness, swollen or inflamed gums, Bell palsy, and vitamin B12 or zinc deficiency. Some medicines, including thyroid medicines and certain antibiotics, are on the list too. Taste usually fades after age 60, with salty and sweet going first. A dry mouth is a frequent contributor, covered in the dry mouth guide.

Safety at home when smell is gone

MedlinePlus gives practical advice. Use smoke detectors, and consider electric appliances rather than gas because you may not smell a leak, or install a gas fume detector. Label the date food items were opened, because spoiled food may not smell off. Adding highly seasoned foods can stimulate the taste sensations that remain. If you smoke, stopping helps taste, and the quitting smoking guide explains how a provider can help. These are simple steps worth taking while the cause is being sorted out.

What a visit usually involves

The provider performs a physical exam and asks when the problem developed, whether all odors or only some are affected, whether taste is affected, whether you have cold or allergy symptoms and what medicines you take. MedlinePlus says the provider will look at and around the nose. Tests that may be performed include a CT or MRI scan, nasal endoscopy, olfactory nerve testing and smell testing. Those are specialist tests and referrals, not services this practice lists. The vitamin D and B12 guide explains one blood test that is available.

What improves and when to follow up

Treating the cause may correct the loss. MedlinePlus lists antihistamines for allergies, changes to other medicines, surgery to clear blockages and treatment of other disorders. Olfactory retraining using familiar odors may help a minority of patients. If the loss follows a recent upper respiratory infection, it says to be patient, since smell often returns on its own. It advises contacting your provider if the loss continues or worsens, or if you have other unexplained symptoms. Loss due to aging usually has no treatment.

Sources

• MedlinePlus — Smell, impaired
• MedlinePlus — Taste, impaired