A Reduced Sense of Smell 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 certain odors 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. If You Can't Detect Odor at All Other people can't detect odor at all, which is called anosmia. This type of smell disorder is sometimes the result of head trauma in the nose region, usually from an automobile accident or chronic nasal or sinus infections. It can sometimes be caused by aging. In rare cases, anosmia is inherited. If Your Sense of Smell Is Distorted 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. Questions To Ask Yourself If you think you have a problem with your sense of smell, try to identify and record the circumstances at the time you first noticed the problem. 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?  - Was I exposed to air pollutants, pollens, pet dander, or dust to which I might be allergic?   - Is this a recurring problem?   - Does it come at any special time, like during the hay fever season? When did I first become aware of it? Did I have a cold or the flu? Did I have a head injury? Was I exposed to air pollutants, pollens, pet dander, or dust to which I might be allergic? Is this a recurring problem? Does it come at any special time, like during the hay fever season? Bring this information with you when you visit your physician. Also, be prepared to tell him or her about your general health and any medications you are taking. Talking With Your Doctor Diagnosis by a doctor is important to identify and treat the underlying cause of a potential smell disorder. Your doctor may refer you to an otolaryngologist, a specialist in diseases of the ear, nose, and throat. An accurate assessment of a smell disorder will include, among other things, - a physical examination of the ears, nose, and throat   - a review of your health history, such as exposure to toxic chemicals or injury, and   - a smell test supervised by a health care professional. a physical examination of the ears, nose, and throat a review of your health history, such as exposure to toxic chemicals or injury, and a smell test supervised by a health care professional. Tests for Smell Disorders Some tests measure the smallest amount of odor you can detect. You also may receive a "scratch and sniff" test to determine how well you can identify various odors from a list of possibilities. In this test, the odor is embedded in a circular pad on a piece of paper and released when scratched. In this way, doctors can determine whether a person has a decreased ability to smell (hyposmia), the inability to detect any odors (anosmia), or another kind of smell disorder. In some cases, your doctor may need to perform a nasal examination with a nasal endoscope, an instrument that 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 upper regions of the nose and nasal sinuses that can't be seen by an endoscope are involved, he or she may order a specialized X-ray procedure, usually a CT scan, to look further into the nose and sinuses. When to See the Doctor 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.