Impaired smell is the partial or total loss or abnormal perception of the sense of smell.
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.
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
- Infections in nose, throat, or sinuses
- Endocrine disorders
- Dementia or other neurological problems
- Nutritional deficiencies
- Head injury or nasal or sinus surgery
- Radiation therapy to head or face
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 medicine
- 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:
- The loss of smell continues or is getting worse
- You have other unexplained symptoms
What to Expect at Your Office Visit
The 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 provider will look at and around your nose. Tests that may be performed include:
If the loss of sense of smell is caused by a stuffy nose (nasal congestion), decongestants or antihistamines may be prescribed.
Other treatments for a stuffy nose may include:
- 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 as a shot.
- Nasal steroid sprays may be prescribed.
Loss of smell; Anosmia; Hyposmia; Parosmia
Baloh RW, Jen J. Smell and taste. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 427.
Leopold DA, Holbrook EH. Physiology of olfaction. In: Flint PW, Haughey BH, Lund LJ, et al, eds. Cummings Otolaryngology: Head & Neck Surgery. 6th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 39.
Update Date 8/5/2015
Updated by: Sumana Jothi MD, specialist in laryngology, Clinical Instructor UCSF Otolaryngology, NCHCS VA, SFVA, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.