There are several types of smell disorders depending on how the sense of smell is affected. People who have smell disorders experience either a loss in their ability to smell or changes in the way they perceive odors.
Some people have hyposmia, which occurs when their ability to detect odor is reduced. This smell disorder is common in people who have upper respiratory infections or nasal congestion. This is usually temporary and goes away when the infection clears up.
Other people can’t detect odor at all, which is called anosmia. This type of smell disorder is sometimes the result of head trauma, usually from an automobile accident. It can sometimes be caused by aging. In rare cases, anosmia is inherited.
Sometimes a loss of smell can be accompanied by a change in the perception of odors. This type of smell disorder is called dysosmia. Familiar odors may become distorted, or an odor that usually smells pleasant instead smells foul. Sometimes people with this type of smell disorder also experience headaches, dizziness, shortness of breath, or anxiety.
Still others may perceive a smell that isn’t present at all, which is called phantosmia.
If you think you have a problem with your sense of smell, try to identify and record the circumstances surrounding it. Ask yourself the following questions:
• When did I first become aware of it?
• Did I have a cold or the flu?
• Did I have a head injury?
Ask yourself these questions:
• Was I exposed to air pollutants, pollens, danders, or dust to which I might be allergic?
• Is this a recurring problem?
• Does it come at any special time, like during the hayfever season?
Bring this information with you when you visit your physician. Also, be prepared to tell him about your general health and any medications you are taking. The correct diagnosis by a trained health professional can provide reassurance that your problem with smell is not imaginary.
Your doctor may refer you to an otolaryngologist, or specialist in diseases of the ear, nose, and throat. After a complete medical history and physical examination, your doctor may run special tests to determine the extent and nature of your smell disorder.
Some tests measure the smallest amount of odor you can detect. You also may receive an easily administered “scratch and sniff” test — that is commercially available to doctors — to determine how well you can identify various odors from a list of possibilities.
Your doctor may ask you to compare the smells of different chemicals, or to indicate how much the intensity of the smell grows when its chemical concentration is increased. By using these tests, your doctor can determine if you have hyposmia, anosmia, or another type of smell disorder.
In some cases, your doctor may need to perform a nasal examination with a nasal endoscope, an instrument which illuminates and magnifies the areas of the nose where the problem may exist. This test can help identify the area and extent of the problem and help your doctor select the right treatment.
If your doctor suspects that the nerves of smell or other parts of the nose and head that can’t be seen by an endoscope are involved, he or she may order an X-ray, usually a CAT scan, to look further into the nose and sinuses.
If you think you have a smell disorder, see your doctor. Diagnosis of a smell disorder is important because once the cause is found, your doctor may be able to treat your smell disorder. Many types of smell problems are reversible, but if they are not, counseling and self-help techniques may help you cope.
Source: National Institutes of Health
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