Impaired smell is the partial or total loss of the sense of smell.
Loss of smell; Anosmia
The loss of smell can occur as a result of nasal congestion or blockage of the nose and isn't serious, but it can sometimes be a sign of a nervous system (neurological) condition.
Some loss of smell occurs with aging. In most cases, there is no obvious or immediate cause, and there is no treatment.
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:
Many medications may change or decrease the ability to detect odors.
The sense of smell also enhances your ability to taste. Many people who lose their sense of smell also complain of a loss of the sense of taste. Most can still tell between salty, sweet, sour, and bitter tastes, which are sensed on the tongue. They may not be able to tell between other flavors. Some spices (such as pepper) may affect the nerves of the face and may be felt rather than smelled.
Treating the cause of the problem may correct loss of the sense of smell. Treatment can include:
Avoid using too many nasal decongestants, which can lead to recurring nasal congestion.
If you lose your sense of smell, you may have changes in taste. But, adding highly seasoned foods to your diet can help stimulate the taste sensations that you still have.
Improve your safety at home by using smoke detectors and electric appliances instead of gas ones. You may not be able to smell gas if there is a leak. Or, install equipment that detects the presence of gas fumes in the home.
There is no treatment for loss of smell due to aging.
If you have a loss of smell due to a recent viral upper respiratory infection, be patient. The sense of smell may return to normal without treatment.
Call your health care provider if the loss of smell continues, is getting worse, or if you have other unexplained symptoms.
The doctor will perform a physical exam and ask questions about your medical history and current symptoms. Questions may include:
The doctor will look at your nose and surrounding structures. Tests that may be performed include:
In some cases, surgery (biopsy) to remove a piece of the cells responsible for smell (olfactory epithelium) may be needed to make a diagnosis.
If the loss of sense of smell is caused by a stuffy nose (nasal congestion), decongestants or antihistamines may be prescribed.
A vaporizer or humidifier may prevent mucus from drying and improve nasal discharge.
Steroid nasal sprays or pills may be recommended.
Vitamin A may be given by mouth or with a shot (injection).
Leopold DA, Holbrook EH. Physiology of olfaction. In: Cummings CW, Flint PW, Haughey BH, et al, eds. Otolaryngology: Head & Neck Surgery. 4th ed. Philadelphia, Pa: Mosby Elsevier; 2005:chap 37.
Lafreniere D, Mann N. Anosmia: Loss of smell in the elderly. Otolaryngol Clin North Am. 2009 Feb 1;42(1):123-131.