Loss of smell — anosmia (an-OZ-me-uh) — means no odors can be detected; this complete loss of smell is fairly rare. Loss of smell can be temporary or permanent, depending on the cause. Hyposmia is a reduced ability to smell and to detect odors and is a more common condition.
Loss of smell is rarely a symptom of a serious condition. Still, a functioning sense of smell is necessary to fully taste and enjoy food. Loss of smell can cause you to lose interest in eating which can cause excessive weight loss and even depression.
Taste and smell disorders send hundreds of thousands of Americans to the doctor each year. Some of the causes include allergies, nasal polyps, viral infections, head trauma and rarely, sinus and brain tumors. Fortunately, for most people, loss of smell is a temporary nuisance caused by a severely stuffy nose from a cold.
For some people, including many elderly, the loss of a sense of smell may persist. In addition, problems with sense of smell can be a sign of a more serious medical condition. Hyposmia might be a very early sign of Parkinson's disease. Hyposmia is also an early and common finding in Alzheimer's disease and other dementias. Any ongoing problems with smell should be checked out by a doctor.
If you experience a loss of smell that you can't attribute to a cold or allergy or which doesn't get better after a week or two, tell your doctor. Your doctor can take a look inside your nose with a special instrument to see if a polyp or growth is impairing your ability to smell or if an infection is present. Anosmia can be caused by something physically blocking the flow of air through your nose. You can also lose your sense of smell if any part of the olfactory pathway is damaged or destroyed. Your olfactory system, which provides your sense of smell, consists of receptors in the mucous lining of your nose that sends information through nerves into your brain. There are several diseases that can interfere with your olfactory system and further testing by a doctor who specializes in nose and sinus problems -- an ear, nose, and throat (ENT) doctor or otolaryngologist -- may be needed to determine the cause of anosmia. A CT scan or MRI scan may be necessary so that the doctor can get a better look of the area and rule out a tumor.
If nasal congestion from a cold or allergy is the cause of anosmia, treatment is usually not needed, and the problem will get better on its own. Short-term use of over-the-counter decongestants may open up your nasal passages so that you can breathe easier. However, if the congestion gets worse or does not go away after a few days, see your doctor. You may have an infection and need antibiotics, or another medical condition may be to blame.
If a polyp or growth is present, surgery may be needed to remove the obstruction and regain your sense of smell.
If you suspect a medication is affecting your sense of smell, talk to your doctor and see if there are other treatment options available that won't affect your ability to smell. However, never stop taking a medication without first talking with your doctor.
Sometimes a person will regain his or her sense of smell spontaneously. Some nasal and sinus subspecialists (rhinologists) can recommend olfactory retraining to attempt to recover your sense of smell. Unfortunately, anosmia is not always treatable, especially if age or olfactory nerve damage is the cause.