Volume 7 Issue 225
Published - 14:00 UTC 08:00 EST 13-Aug-2005 
Next Update - 14:00 UTC 08:00 EST 14-Aug-2005

Editor: Susan K. Boyer, RN
Vidyya.
All rights reserved.

  

 




About problems with smell

(13 August 2005: VIDYYA MEDICAL NEWS SERVICE) -- Problems with smell are common in older people. Thirty percent of older Americans between the ages of 70 and 80 have a problem with their sense of smell. Two out of three people over 80 have a problem with their sense of smell.

Problems with smell can have a big impact on the lives of older people. Our sense of smell lets us fully enjoy the scents and fragrances in the environment, like roses, coffee, and rain.

Photo of food and beverages

Smell is also important to our appreciation of food; without smell we would not be able to fully enjoy the flavors of food and beverages. But, even more important, smell can be a warning signal that something is wrong in our environment. Smell helps us to know when food is spoiled or if there is a gas leak.

The sense of smell is part of our chemical sensing system or the "chemosenses." Normal smell occurs when odors around us, like the fragrance of flowers or the smell of baking bread, stimulate the olfactory, or small nerve cells, that are responsible for the sense of smell. The olfactory cells are located in a small patch of tissue high inside the nose.

Odors release microscopic molecules into the environment and stimulate these small nerve cells. Once the cells detect the molecules, they send messages to our brain, where we identify smell.

For most people a problem with smell is a minor irritation, but for others it may be a sign of more serious diseases and conditions.

When people have a problem with smell, they may experience total or partial loss of smell. They can sometimes think they smell bad odors that are not actually present. People with smell disorders usually have problems appreciating food flavors, too.

Smell and taste are closely linked in the brain, but are actually distinct sensory systems. True tastes are detected by taste buds on the tongue and are limited to sweet, salty, sour, bitter, savory and perhaps a few other sensations.

Many people mistakenly believe they have a problem with taste, when they are really experiencing a problem with their sense of smell. Loss of smell occurs a lot more frequently than loss of taste.

Photo of woman smelling rosesThe sense of smell does gradually decline in older people. Many older people are not even aware that they have a problem with their sense of smell. They may not even notice that they are experiencing a loss of smell until it becomes very troubling.

Although problems with smell are rarely life-threatening, loss of smell can be dangerous. Identifying smells is your brain's way of providing you with information about your environment and keeping you safe. The sense of smell often serves as a first warning signal, alerting us to the smoke of a fire or the odor of a natural gas leak and dangerous fumes.

When smell is impaired, food loses its appeal and we may eat too much and gain weight or eat too little and lose too much weight. Loss of smell may also cause us to eat too much sugar or salt to make our food taste better. This can be a problem for people with certain medical conditions, such as diabetes or high blood pressure. In severe cases, loss of smell can lead to depression.

Loss of smell may be an early sign of a more serious disease, such as multiple sclerosis. Getting a diagnosis early will help an individual deal better with the underlying condition or disease.

Research shows that people with a total or partial loss of smell are almost twice as likely as people with normal smell to have certain kinds of accidents.

The most common types of accidents in order of frequency involve

  • cooking

  • eating or drinking spoiled foods or toxic substances

  • failing to detect gas leaks or fires

Our sense of smell is most accurate under the age of 60. Women of all ages are generally more accurate than men at identifying odors. Only about one to two percent of people under the age of 65 will experience some problem with their sense of smell. After the age of 65, loss of the sense of smell increases.

Many older people believe there is nothing they can do about their diminished sense of smell. Depending on the cause of your problem, your doctor may be able to treat your smell disorder or suggest new ways to cope with the loss of smell. If you think you have a problem with your sense of smell, see your doctor.

Quiz

1. A person with a smell disorder may experience

A. a total loss of smell

B. partial loss of smell

C. a problem with taste

D. all of the above


D is the correct answer. When people have a problem with smell, they may experience total or partial loss of smell. They can sometimes think they smell bad odors that are actually not present. People with smell disorders have problems appreciating food flavors, too.


2. Our sense of smell is most accurate

A. under the age of 60

B. after the age of 80

C. at birth

D. during adolescence


A is the correct answer. Our sense of smell is most accurate under the age of 60 years old.


3. Losing your sense of smell can

A. cause you to eat too little

B. be an early sign of disease

C. keep you from knowing that food is spoiled

D. all of the above


D is the correct answer. When smell is impaired, food loses its appeal and we may eat too much and gain weight or eat too little and lose too much weight. Loss of smell may be an early sign of a more serious disease. The sense of smell also serves as a first warning signal, alerting us when food is spoiled.


4. A person who suspects a loss of smell should

A. wait to see if it gets better

B. see a doctor and explain exactly how he or she noticed the change

C. wait to see if it gets worse


B is the correct answer. If you suspect a loss of smell, you should see your doctor and tell him or her exactly how you noticed the change.



Causes and Prevention

Problems with smell happen for many reasons, some clearer than others. Loss of smell may be permanent or temporary, depending on the cause.

As with vision and hearing, people gradually lose their ability to smell as they get older. Smell that declines with age is called presbyosmia and is not preventable.

Age is only one of the many reasons that problems with smell can occur. Some people are born with a poor sense of smell, but this is not the case for most people.

Most people who develop a problem with smell have recently had an illness or injury. The most common causes are the common cold and chronic nasal or sinus disease.

Other common causes of smell disorders are

  • head injuries

  • allergies

  • exposure to airborne toxic chemicals.

Swollen sinuses and nasal passages often result in problems with smell. These conditions may cause total or partial loss of smell. The problem usually diminishes or goes away when the underlying medical condition clears up.

You can help prevent problems with smell caused by respiratory infections and colds by washing your hands frequently, especially during the winter months. Hand washing helps protect you from getting respiratory infections and colds.

If your smell disorder is caused by allergies, you should avoid allergens, like ragweed, grasses, and pet dander. Also, get a flu shot every year to prevent influenza and other serious respiratory conditions that can result from the flu.

Loss of smell can be caused by nasal polyps, which are small, non-cancerous growths in the nose or sinuses that can block the ability of aromas to reach nerve cells high up in the nose. Removing the polyps may restore smell. In rare cases, benign non-malignant tumors grow on the nerves of smell, causing a loss of smell.

Photo of bikersPrevious surgery or trauma to the head can upset your sense of smell because the nerves that are involved in smell may be cut, blocked, or damaged by scar tissue. Automobile accidents are among the most frequent causes of trauma to the head. Everyone should wear a seat belt, and those who participate in sports, such as bicycling, should wear protective helmets.

People with head and neck cancers who receive radiation treatment to the nasal regions are among those who experience problems with their sense of smell. Older people who have lost their larynx or voice box commonly complain of poor ability to smell and taste.

Tobacco smoking is the most concentrated form of pollution that most people are exposed to. It impairs the ability to identify odors. Quitting smoking is one thing you can do right now to prevent loss of smell and improve your sense of smell.

Sometimes exposure to certain chemicals, such as insecticides and solvents, and some chemicals found in the workplace can decrease the sense of smell. Avoid contact with these substances, or if you do come in contact with them, see your doctor.

If you are taking certain medicines, you may notice a change in your ability to smell. Certain antibiotics, some blood pressure pills, some cholesterol-lowering drugs, and some antifungal medications can cause problems with smell. This occurs rarely, but it can happen.

If you are taking these medications and notice a change in your sense of smell, talk to your doctor. You may be able to adjust or change your medicine to one that will not cause a problem with smell. Sometimes it is difficult to determine if the cause of the smell disorder is the medication or the underlying condition.

Other less common causes of smell disorders are thyroid abnormalities and vitamin deficiencies. Malnutrition and diabetes also can be linked to smell disorders. If you have any of these conditions and experience a loss of smell or taste, tell your doctor. In some cases, when the condition that is causing the problem with smell is treated, the sense of smell returns.

Sometimes a problem with smell can be a sign of a more serious health problem, such as diseases of the nervous system, like multiple sclerosis, or, in rare cases, a brain tumor. Loss of smell may be the first sign that something is wrong.

Check with your doctor if you've been experiencing a problem with your sense of smell for a while. You may be able to prevent or get early treatment for a more serious health problem.

Quiz

1. Problems with smell can be caused by

A. the common cold

B. head injuries

C. sinus infections

D. all of the above


D is the correct answer. Most people who develop a problem with smell have recently had an illness or injury. The most common causes are upper respiratory infections and head injuries.


2. Smell that declines with age is called

A. presbyosmia

B. hyposmia

C. hyperosmia

D. myosmia


A is the correct answer. Smell that declines with age is called presbyosmia.


3. You can help prevent loss of smell due to respiratory infections by

A. blowing your nose frequently

B. washing your hands frequently

C. taking antifungal medication

D. talking less frequently


B is the correct answer. You can help prevent loss of smell due to respiratory infections by washing your hands frequently. Hand washing can help protect you from getting respiratory infections and colds.


4. Medicines that may affect your sense of smell are

A. vitamins

B. antibiotics and high blood pressure pills

C. over-the-counter medicines

D. vaccines


B is the correct answer. Antibiotics and high blood pressure pills are medicines that may affect your sense of smell.



Symptoms and Diagnosis

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?

Photo of doctor and patientBring 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.

Quiz

1. People who can't detect odor at all have hyposmia.

FALSE is the correct answer. People who can't detect odor at all have anosmia.

2. A loss of smell can be accompanied by a change in the perception of odors.

TRUE is the correct answer. Familiar odors may become distorted, or an odor that normally smells pleasant instead smells foul.

3. Some people with severe head injuries completely lose their sense of smell.

TRUE is the correct answer. Head trauma, usually caused by an automobile accident, can result in total loss of smell.

4. If you have a problem with your sense of smell, your family doctor may refer you to an ophthalmologist for further testing.

FALSE is the correct answer. Your doctor may refer you to an otolaryngologist, or specialist in diseases of the ear, nose, and throat. An ophthalmologist is a specialist in the structure, function, and diseases of the eye.

Treatment and Research

Although there is no treatment for presbyosmia -- loss of smell due to aging -- relief from smell disorders is possible for many older people. Depending on the cause of your problem with smell, your doctor may be able to treat your problem with smell or suggest ways to handle it. Scientists are studying how our sense of smell works so that new treatments can be developed.

Sometimes a certain medication causes a smell disorder, and improvement occurs when the medicine causing the problem is stopped or changed. Although certain medications can cause a loss of smell, others -- in particular, anti-allergy medicines -- seem to improve smell and sometimes taste.

If you take medications, ask your doctor if they can affect your sense of smell. If so, ask if you could substitute other medications or reduce the dose. Your doctor will work with you to get the medicine you need while trying to reduce unwanted side effects.

Other common causes of smell loss, like the common cold or seasonal allergies, are usually temporary. Smell is regained by waiting for the illness to run its course. In some cases, nasal obstructions, such as polyps, can be removed to restore airflow through the nasal passages and restore the sense of smell.

Your doctor may suggest oral steroid medications like prednisone, which is usually used for a short period of time, or topical steroid sprays, which can be used chronically. Occasionally, the sense of smell returns to normal on its own without any treatment.

If you have a problem with smell, there are some things you can do:

  • Wait it out. If you have had a cold with a stuffy nose, chances are in a few days your sense of smell will return. However, you should not wait to see your doctor if you think something more serious has caused your loss of smell or you have had the problem for a while. Loss of smell can sometimes mean a more serious condition exists.

Photo of women walking
  • Sweat it out. If your nose is stuffed up from a cold, sometimes mild exercise or the steam from a hot shower may open up your nasal passages.

  • Stop smoking. Smoking causes long-term damage to your sense of smell. If you quit smoking, you may notice some improvement.

  • Check with your doctor. If your sense of smell seems to have disappeared, changed, or you've noticed the problem for a while, see your doctor for help. Sometimes, especially with a sinus infection, taking antibiotics for a short period of time may remedy the problem. If there is a blockage or you have a chronic sinus condition, outpatient surgery may be called for.

If you do not regain your sense of smell, there are things you should do to ensure your safety. Take extra precautions to avoid eating food that may have spoiled. If you live with other people, ask them to smell the food to see if it is fresh. People who live alone should discard food if there is a chance it is spoiled. Other home safety measures include installing smoke alarms and gas detectors.

For those who wish to have additional help, there may be support groups in your area. These are often associated with smell and taste clinics. Some on-line bulletin boards also allow people with smell disorders to share their experiences. Not all people with smell disorders will regain their sense of smell, but most can learn to live with it.

The National Institute on Deafness and Other Communication Disorders funds basic and clinical studies of smell disorders. Scientists are working to understand more about the sense of smell so that new treatments can be developed to help restore the sense of smell to people who have lost it.

Scientists are finding out more about how our sense of smell works and how we detect and smell the many different compounds that form odors. These findings are helping scientists study the sense of smell as a model for other sensory systems in the body.

Like other senses in our bodies, our sense of smell can be greatly affected simply by growing older. Researchers are studying why and how these age-related changes in smell occur.

Also, smell cells -- and taste cells -- are the only sensory cells that are regularly replaced throughout life. Understanding why this happens may help researchers develop ways to replace damaged sensory cells, and restore smell.

Scientists have found that loss of smell affects the choices an older person makes about eating certain foods. They are looking at how and why this takes place in order to develop more effective ways to help older people -- especially those with chronic illnesses -- cope better with problems with smell.

Quiz

1. People sometimes regain their sense of smell once an illness has run its course.

TRUE is the correct answer. Some common causes of smell disorders, like the common cold, upper respiratory infections, and seasonal allergies, are usually temporary and smell returns when the illness has run its course.

2. You should hold off on seeing your doctor if you have had a problem with your sense of smell for a while.

FALSE is the correct answer. You should see your doctor if you have had the problem with your sense of smell for a while or if you think the cause may be serious. Sometimes, loss of smell can mean a more serious condition exists.

3. If you have lost your sense of smell, you should install a gas detector and smoke alarm in your home.

TRUE is the correct answer. People with smell disorders need to take extra precautions to ensure their safety, because they cannot detect potentially dangerous situations such as a gas leak. Home safety measures include installing smoke alarms and gas detectors.

4. All people with smell disorders will eventually regain their sense of smell.

FALSE is the correct answer. Not all people with smell disorders will regain their sense of smell, but most can learn to live with it. Counseling, support groups, and other self-help techniques can help older people cope with loss of smell.

Frequently Asked Questions

1. What is our sense of smell?

Our sense of smell is the ability to detect odors in our environment, like the fragrance of flowers or the smell of baking bread. Smell is also the ability to detect food odors released in our mouths when we eat, which then flow from the throat to the nose. Smell is part of our chemical sensing system, or the "chemosenses."

2. Why is smell important?

Smell is important because it lets us fully enjoy scents and fragrances, and contributes greatly to our enjoyment of food and beverages. But, even more important, smell can be a warning sign that something is wrong in our environment. Smell helps us to know when food is spoiled or if there is a gas leak.

3. Do people confuse smell problems with taste problems?

Yes. Many people mistakenly think they have a problem with taste, when what they are really experiencing is a problem with smell. It is common for people who lose their sense of smell to think that food has lost its taste. This is usually not the case. The food has lost its aroma, but tastes, such as sweet, salty, sour, and bitter, remain.

4. How common are problems with our sense of smell?

Photo of woman smelling rosesRoughly 200,000 people each year visit a doctor for either a smell or taste problem. Thirty percent of older Americans between the ages of 70 and 80 have a problem with their sense of smell. Two out of three people over the age of 80 have a problem with their sense of smell, with men affected more often than women.

Some studies estimate that more than two million people in the United States have problems with smell and taste. The number may be much higher, because many cases are not reported.

5. What impact can loss of smell have on an older person's life?

Older people who have lost their sense of smell may eat too much or eat too little. In severe cases, loss of smell can lead to depression. Although problems with smell are rarely life-threatening, loss of smell can be dangerous. Identifying smells is your brain's way of providing you with information about your environment and keeping you safe.

6. How does normal smell occur?

Normal smell occurs when the odors around us release microscopic molecules into the environment that stimulate small nerve cells, called olfactory cells, located high up in the nose. Once the cells detect the molecules, they send messages to our brains, where we identify the smell.

7. How do I know if I have a problem with my sense of smell?

There are several types of smell disorders depending on how the sense of smell is affected. If you have a smell disorder, you may experience a decrease in your ability to smell or changes in the way you perceive odors. Or you may not be able to detect any odor at all.

Sometimes, familiar odors may become distorted, or an odor that usually smells pleasant instead smells foul. Some people with smell disorders perceive a phantom smell or a smell that isn't there at all.

8. What are some of the common causes of smell disorders?

Most people who have a problem with smell have recently had an illness or injury. The most common causes are upper respiratory infections, such as the common cold, and chronic sinus or nasal disease. Other common causes are head injuries and exposure to toxic chemicals.

Photo of bikers

Nasal polyps can block the ability of aromas to reach nerve cells. People with head and neck cancers who receive radiation treatment to the nasal area can also experience problems with smell.

9. Can I do anything to prevent a smell disorder from occurring?

Problems with smell that occur with aging are not preventable. Loss of smell caused by respiratory infections and colds can be prevented by washing your hands frequently, especially during the winter months.

If your smell disorder is caused by allergies, you should avoid allergens, like ragweed, grasses, and pet dander. Quitting smoking also may improve smell and prevent loss of smell.

10. Can certain medicines cause a problem with smell?

In rare cases, certain medicines may cause a change in your ability to smell. Antibiotics and blood pressure pills are among the most common medications that cause a problem with smell. If you are taking these medications and notice a change in your sense of smell, talk to your doctor. You may be able to adjust or change your medicine to one that will not cause a problem with smell.

Sometimes it is difficult to determine if the problem with smell is caused by medication or the underlying condition.

11. Are there certain medical conditions and/or diseases that are associated with smell disorders?

Sometimes a problem with smell can be a sign of a more serious health problem, such as a disease of the nervous system, like Parkinson's disease, Alzheimer's disease, or multiple sclerosis. In rare cases, it can be a sign of a brain tumor. Malnutrition and diabetes also can be accompanied or signaled by chemosensory problems, like smell disorders.

12. Can a person completely lose their sense of smell?

In rare instances, a person can be born without the ability to smell. In other cases, total loss of smell is usually caused by nasal and sinus disease or head injury. If the nerves involved in the sense of smell are severed, either by trauma or surgery, complete loss of smell will occur.

13. Can losing your sense of smell be serious?

Losing smell can be more than a quality-of-life issue. Loss of smell deprives us of an early warning system that most of us take for granted. Smell helps us detect spoiled food and beverages. It also alerts us to the smoke of a fire, the odor of dangerous fumes, or a gas leak.

Loss of smell can also be a first sign of a more serious condition or disease. In some cases, especially in older people, loss of smell can interfere with normal eating patterns, causing us to eat too much or too little, and may even lead to depression.

14. How are smell disorders diagnosed?

Scientists have developed tests to determine the nature and extent of a person's smell disorder. Tests measure the smallest amount of odor patients can detect as well as their accuracy in identifying different smells.

An easily administered "scratch and sniff" test allows a person to scratch pieces of paper treated to release different odors, sniff them, and try to identify each odor from a list of possibilities. In this way, doctors can easily determine whether a person has hyposmia, a decreased ability to smell, anosmia, the inability to detect any odors, or another kind of smell disorder.

15. Can smell disorders be treated?

Depending on the cause of your smell disorder, your doctor may be able to treat your problem or suggest ways to cope with it. If a certain medication is the cause of the disorder, stopping or changing the medicine may eliminate the problem.

Some patients with respiratory infections or allergies regain their sense of smell when the illness or condition is over. Often, correcting a general medical problem also can restore the sense of smell.

Photo of women walkingFor patients with nasal obstructions, such as polyps, or other inflammatory conditions of the nose or sinuses, medical treatments or surgery can restore the sense of smell. Occasionally, the sense of smell returns to normal on its own, without any treatment.

16. What can I do if my medication is causing me to have a problem with my sense of smell?

Photo of doctor and patientSee your doctor and ask if your medicine could be causing your problem with smell. Some medicines, like antibiotics and high blood pressure pills, are more likely to cause problems. Your doctor may be able to adjust your medicine or change your medicine. If not, he or she may suggest ways to manage your problem.

Do not stop taking your medicine unless directed by your doctor. To reduce unwanted side effects, your doctor may try to find a new medicine for you or reduce the dose of your medicine.

17. What should I do if I think I have a problem with my sense of smell?

The best thing you can do is see your doctor. Proper diagnosis by a trained professional, such as an otolaryngologist, is important. These physicians specialize in disorders of the head and neck, especially those related to the ear, nose, and throat. Diagnosis may lead to an effective treatment of the underlying cause of your smell disorder.

Many types of smell disorders are curable, and for those that are not, counseling is available to help you cope.

18. How can I best talk to my doctor about my problem with smell?

You can help your doctor make a diagnosis by writing down important information about your problem beforehand and giving the information to your doctor during your visit.

Write down answers to the following questions:

  • When did I first become aware of the problem?

  • Did I have the cold or the flu?

Write down answers to these questions:

  • Did I have a head injury?

  • 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?

19. What research is being done on smell disorders?

The National Institute on Deafness and Other Communication Disorders supports basic and clinical studies of smell disorders. Scientists are working to understand more about the sense of smell so that new treatments can be developed to help restore the sense of smell to those who have lost it.

Scientists are finding out more about how our sense of smell works and how we detect and smell the many different compounds that form odors. These findings are helping scientists study the sense of smell as a model for other sensory systems in the body.

Scientists have also found that the loss of smell affects the choices an older person makes about eating certain foods. They are looking at how and why this takes place in order to develop more effective ways to help older people -- especially those with chronic illnesses -- cope better with problems with smell.


Return to Vidyya Medical News Service for 13 August 2005