Anosmia (an-OZ-me-uh), otherwise known as loss of smell, means no odors can be detected. This total loss of smell is quite rare. Depending on the cause, loss of smell can be permanent, or temporary. Hyposmia is a much more common condition. Hyposmia is not a total loss of smell, but a reduced ability to smell and to detect odors.
Typically, loss of smell is not a symptom of a serious condition. Still, a properly functioning sense of smell is required to fully enjoy and taste food. Interest in eating can be affected by loss of smell, which can potentially lead to excessive weight loss and even depression.
Each year, thousands of Americans are sent to the doctor by taste and smell disorders. Some of the causes include viral infections, nasal polyps, allergies, head trauma and rarely, sinus and brain tumors. Luckily, for most individuals, loss of smell is a temporary problem caused by a severely stuffy nose from a cold.
For some individuals, including many elderly people, the loss of a sense of smell can be persistent. Also, issues with sense of smell can be a signal of a more serious medical condition. Hyposmia can be a very early sign of Parkinson's disease. Hyposmia is also an early and common finding in Alzheimer's disease and other dementias. A doctor should look at any continuing issues with loss of smell.
If you are experiencing a loss of smell that cannot be linked to an allergy or cold, which does not get better after a couple weeks, you should inform your doctor. Your doctor can examine the inside of your nose with a special instrument to see if a growth or polyp is hindering your ability to smell or if an infection is present in the area. Anosmia can be brought on by something physically blocking the air passage through your nose. The system that provides your sense of smell, consists of receptors in the mucous lining of your nose that sends information through nerves into your brain, this system is the olfactory system. You can lose your sense of smell if any part of the olfactory pathway is damaged or destroyed. There are multiple 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 MRI scan or a CT scan may be required so that the health care professional can get a better look of the area and rule out a tumor.
If anosmia is caused by nasal congestion from a cold or allergy, treatment is usually not necessary, and the issue will resolve and improve on its own. Over-the-counter decongestants for a short period of time may open up your nasal passages so that you can breathe easier. However, if the congestion worsens or does not go away after a couple of days, see your doctor. You may need antibiotics due to infection, or another medical condition may be the reason.
If you have reason to believe a medication is affecting your sense of smell, speak with your doctor and see if there are other treatment options available that will not affect your ability to smell. However, never stop taking a medication without first discussing the situation with your doctor.
Occasionally an individual will recover his or her sense of smell spontaneously. Some nasal and sinus subspecialists (rhinologists) can recommend olfactory retraining, in an attempt to recover your sense of smell. Unfortunately, anosmia is not always treatable, especially if olfactory nerve damage or age is the cause of the problem.
If a growth or polyp is present, surgery may be required to remove the obstruction and regain your sense of smell.