Smell - impaired
Impaired smell is the partial or total loss or abnormal perception of the sense of smell.
Loss of smell; Anosmia; Hyposmia; Parosmia
The loss of smell can occur with conditions that prevent air from reaching smell receptors located high in the nose, or loss of or injury to the smell receptors. Loss of smell is not serious, but can sometimes be a sign of a nervous system condition.
Temporary loss of the sense of smell is common with colds and nasal allergies, such as hay fever (allergic rhinitis). It may occur after a viral illness.
Some loss of smell occurs with aging. In most cases, there is no clear cause, and there is no treatment.
The sense of smell also enhances your ability to taste. Many people who lose their sense of smell also complain that they lose their 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. You may feel rather than smell them.
Loss of smell can be caused by:
- Medicines that change or decrease the ability to detect odors (such as amphetamines, estrogen, naphazoline, phenothiazines, long-term use of nasal decongestants, reserpine, and possibly zinc-based products)
- Blockage of the nose due to nasal polyps, nasal septal deformities, and nasal tumors
- Respiratory infections and allergies
- Endocrine disorders
- Alzheimer's dementia or other neurological problems
- Nutritional deficiencies
- Head injury or nasal or sinus surgery
- Radiation therapy
Treating the cause of the problem may correct the lost sense of smell. Treatment can include:
Antihistamines (if the condition is due to an allergy)
Changes in medication
Surgery to correct blockages
Treatment of other disorders
Avoid using too many nasal decongestants, which can lead to repeated nasal congestion.
If you lose your sense of smell, you may have changes in taste. 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 gas fumes in the home. People with smell loss should label when the food item was opened to prevent eating spoiled food.
There is no treatment for loss of smell due to aging.
If you have a loss of smell due to a recent upper respiratory infection, be patient. The sense of smell may return to normal without treatment.
When to Contact a Medical Professional
Call your health care provider if:
What to Expect at Your Office Visit
The health care provider will perform a physical exam and ask questions about your medical history and current symptoms. Questions may include:
- When did this problem develop?
- Are all odors affected or only some? Is your sense of taste affected?
- Do you have cold or allergy symptoms?
- What medicines do you take?
- Do you have any other symptoms?
The health care provider will look at and around your nose. Tests that may be performed include:
- CT scan
- MRI scan
- Nasal endoscopy
- Olfactory nerve testing
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 help keep mucus loose and moving.
Steroid nasal sprays or pills may be recommended.
Vitamin A may be given by mouth or with a shot.
Leopold DA, Holbrook EH. Physiology of olfaction. In: Flint PW, Haughey BH, Lund LJ, et al, eds. Otolaryngology: Head & Neck Surgery. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2010:chap 41.
Baloh RW, Jen J. Smell and taste. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 435.