Smell - impaired

Definition:

This is the loss or impairment of the sense of smell.

Alternative Names:

Loss of smell; Anosmia

Considerations:

The loss of smell is usually an insignificant result of nasal congestion or obstruction, but it can sometimes indicate a neurological disorder. Loss of the sense of smell may be idiopathic (without any identifiable cause).

Some loss of smell occurs normally with aging. In most cases, there is no obvious or immediate cause, and there is no treatment.

Temporary loss of the sense of smell is common with colds and nasal allergies, such as hay fever (allergic rhinitis). It may occur following a viral illness.

The sense of smell is often lost with disorders that prevent air from reaching the part of the nose where smell receptors are located (the cribriform plate, located high in the nose). These disorders may include nasal polyps, nasal septal deformities, and nasal tumors.

Other disorders that may cause a loss of the sense of smell include tumors of the head or brain, head trauma, and a wide variety of endocrine, nutritional, Alzheimer's dementia, and nervous disorders.

Many medications may change or decrease the ability to detect odors.

Most people who lose the sense of smell can differentiate salty, sweet, sour, and bitter tastes. These tastes are sensed on the tongue. They may not be able to distinguish other flavors. Some spices (such as pepper) may stimulate facial nerves and may be sensed rather than smelled.

Common Causes:

natural aging process
recent viral upper respiratory infection
nasal decongestants
lead poisoning
drugs (such as amphetamines, estrogen, naphazoline, phenothiazines, prolonged use of nasal decongestants, reserpine)
radiation therapy
nasal or sinus surgery
tracheostomy
nasal or brain tumors

Home Care:

Treatment of underlying disorders may correct loss of the sense of smell. This can include antihistamines (if the condition is related to allergy), surgical correction of physical blockages, treatment of other disorders, changes in medication, and so on. Avoid excessive use of nasal decongestants, which can lead to recurring nasal congestion.

If loss of the sense of smell is permanent, dietary counseling may include use of highly seasoned foods and stimulation of taste sensations that remain.

Caution should be taken to ensure safety around the home with smoke detectors and use of electric appliances rather than gas appliances and/or technologies that detect the presence of gas fumes in the home.

For loss of smell caused by aging, there is no treatment.

For loss of smell caused by a recent viral upper respiratory infection, be patient. The symptoms return to normal without treatment. Sometimes zinc supplements are recommended.

Note: Loss of the sense of smell may be temporary, and ability to smell may return spontaneously, especially after colds or viral infections.

Call your health care provider if:

If the loss of smell is persistent, is getting worse, or is accompanied by other unexplained symptoms, call your health care provider.

What to expect at your health care provider's office:

The medical history will be obtained and a physical examination performed.

Medical history questions documenting impaired sense of smell in detail may include:

time pattern
- When did this problem develop?
- Have you always had problems with your sense of smell?
- Is it getting worse?
quality
- Are all odors affected or only certain types?
- Can you taste food?
aggravating factors
- Do you have a cold or other upper respiratory infection?
- Do you have allergies?
- Do you have chronic sinusitis?
- What medications are being taken?
other
- What other symptoms are also present?

The physical examination will include a physical examination of nasal structures.

Diagnostic tests that may be performed include:

CT scan
olfactory nerve testing
sinus transillumination (a light is placed against the face to help determine if the sinus are full of fluid)
X-rays of the skull
MRI scan

Intervention:
If possible, the cause will be treated. If the loss of sense of smell is caused by nasal congestion, local decongestants or antihistamines may be prescribed. A vaporizer or humidifier may be recommended to prevent mucosal drying and improve nasal discharge.

Vitamin A may be given orally (or in some cases) by injection. In some cases, a biopsy of the olfactory epithelium (cells responsible for smell) may be required to make a diagnosis.

After seeing your health care provider:
If a diagnosis was made by your health care provider related to an impaired sense of smell, you may want to note that diagnosis in your personal medical record.

Review Date: 6/4/2002
Reviewed By: Ashutosh Kacker, M.D., Department of Otolaryngology, New York Presbyterian Hospital, New York, NY. Review provided by VeriMed Healthcare Network.

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