• Highlights
• Introduction
• Symptoms
• Causes
• Prognosis
• Risk Factors
• Diagnosis
• Treatment
• Quick-Relief Medications
• Long-Term Relief Medications
• Other Treatments
• Managing Asthma
• Resources
• References

Asthma in adults

Description

An in-depth report on how asthma is diagnosed, treated, and managed in adults.

Managing Asthma

Avoidance or control of the triggers that lead to asthma attacks is as much a priority as treatment of the disease.

Indoor Protection

Controlling Pets. Patients who already have pets and are not allergic to them probably have a low risk for developing allergies. If pets trigger asthma, however, they should be kept outside. If this isn't possible, they should at least be confined to carpet-free areas outside the bedroom. Cats harbor significant allergens, which can even be carried on clothing; dogs usually present fewer problems. Washing animals once a week can reduce allergens. Dry shampoos, such as Allerpet, are now available for both cats and dogs that remove allergens from skin and fur and are easier to administer than wet shampoos.

Controlling for Dust. Spray furniture polish is very effective for reducing both dust and allergens. Air cleaners, filters for air conditioners, and vacuum cleaners with High Efficiency Particle Arresting (HEPA) filters can help remove particles and small allergens found indoors. Neither vacuuming nor the use of anti-mite carpet shampoo, however, is effective in removing mites in house dust. In fact, vacuuming stirs up both mites and cat allergens. If possible, avoid carpets and rugs.

Bedding and Curtains. Many experts recommend reducing exposure to dust mites by enclosing mattresses and pillows in semipermeable coverings. (Vinyl mattress covers limit airflow and may also worsen, or even cause, asthma in children. Synthetic pillows may pose a significantly higher risk for severe asthma attacks in children than feather or no pillows.) However, several 2005 studies suggested that such covers do not prevent asthma or allergies. Replace curtains with shades or blinds, and wash bedding using the highest temperature setting.

Reducing Humidity in the House. Although warm, moist air from vaporizers can greatly ease and moderate asthma attacks, living in a damp house is counterproductive. Dust mites thrive in humidity and damp houses increase the risk for mold, so on-going humidifiers can be unuseful. If they are used, humidity levels should not exceed 40% and they should be cleaned daily with a vinegar solution.

Gas Stoves, Kerosene, and Cooking. People with asthma should choose electric ovens rather than gas, which release nitrogen dioxide, a substance that can aggravate asthma symptoms. Even smoky cooking can worsen asthma. Kerosene (used in space heaters and lamps) may also produce allergic reactions.

Exterminating Pests (Cockroaches and Mice). Use a professional exterminator to eliminate cockroaches. (One study reported that ridding a home of cockroaches and cleaning the house using standard housecleaning techniques failed to eliminate the cockroach allergens themselves.) Exterminate mice and attempt to remove all dust, which might contain mouse urine and dander.

Avoiding Smoking and Cigarette Smoke. Cigarette smoke can accelerate the decline in lung function related to asthma. Even exposure to secondhand smoke can double the risk of asthma-related emergency room visits. In one study, it was the most frequently cited trigger of asthma symptoms. Everyone should quit smoking and encourage others around them to quit. [For help in quitting, see In-Depth Report # 41: Smoking . ]

Outdoor Protection

Avoiding Outdoor Allergens. The following are some recommendations for avoiding allergens outside:

• Avoid scheduling camping and hiking trips during times of high pollen count (generally, May and June for grass pollen and mid-August to October for ragweed).
• Avoid strenuous activity when ozone levels are highest, which usually occur in early afternoon, particularly on hot hazy summer days. Levels are lowest in early morning and at dusk.
• Asthma attacks are often higher during thunderstorms. It is not clear why. Some evidence points to a build-up of ozone that accompanies such storms. One study suggested that changing airflow patterns bring a sudden downdraft of air containing concentrations of pollens, small particles and allergens.
• Patients who are allergic to mold should avoid barns, hay, raking leaves, and mowing grass. Exposure to automobile fumes may worsen asthma. Fungi in car air conditioners can also be a problem.

Reducing Exposure to Air Pollution. A number of studies have linked air pollution to asthma. An important 2000 study found a strong association between higher mortality rates from heart and lung diseases and high levels of specific pollutants (ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide). Some experts point out that asthma rates in North America have increased over recent years while the prevalence of many common air pollutants have declined. Nevertheless, evidence strongly suggests that air pollution can worsen existing asthma and patients should take precautions if they are exposed to polluted air.

Occupational Asthma and Reducing Risk

A number of studies have estimated that between 2 - 26% of adult-asthma cases are related to work history. Some experts encourage doctors to suspect occupational factors in all cases of adult-onset asthma. Although workers who have allergies, who smoke, or both are at higher risk than others, any worker exposed to occupational triggers may be at risk for asthma.

Work-related asthma is one of two types:

• Work-aggravated asthma, in which existing asthma symptoms are triggered by irritants at the workplace.
• Occupational asthma, which is new-onset asthma strongly associated with conditions at work.

Occupational asthma is further categorized as:

• Nonlatent (symptoms occur right after exposure to an irritant, usually high concentrations of gas, fumes, dust, or chemicals).
• Latent (symptoms develop after prolonged exposure to substances in the workplace).

Occupational Triggers. Over 250 substances have been identified as potential occupational triggers of asthma and the list is growing. A few of these chemicals and substances include:

• Isocyanates used in the manufacture of polyurethane, paints, steel, and electronics
• Trimellitic anhydrides (TMA) used in many plastics and epoxies
• Western red cedar, oak, redwood, and mahogany
• Metal salts (platinum, nickel, and chrome) and metal working fluids
• Vegetable dusts (soybeans, grains, flour, cotton, and gums)
• Biologic organisms ( Bacillus subtilis , pancreatic enzymes)
• Xylanase used in the baking industry
• Pharmaceuticals (penicillin, phenylglycine acid chloride)
• Glutaraldehyde used to sterilize medical equipment
• Red dye made from the cochineal insect
• Diacetyl, the main chemical in artificial butter flavoring used in popcorn

Workers in these industries and others, including farmers, hairdressers, and those who work in the garment industries are at risk for asthma.

Preventing Occupational Asthma. In people whose asthma is caused by workplace conditions, improved ventilation or face masks may help.

Sometimes, however, even low levels of chemical substances can trigger an asthma attack. In such cases, leaving the job is the only way to prevent the condition from getting worse. Because such a step can be emotionally and financially threatening, workers should be sure that occupational substances are the cause of the asthma by having a complete check-up by a lung specialist.

If the diagnosis of occupational asthma is certain, patients should obtain advice on available compensation plans for disability. The effects of workplace asthma can be permanent. However, in one study, 70% of people with asthma experienced significant improvement in symptoms after leaving the job.

Medications for Treating Seasonal Allergies

Patients with asthma and chronic allergic rhinitis may require daily medications. Patients with severe seasonal allergies may be advised to start medications a few weeks before the pollen season, and to continue it until the season is over.

Immunotherapy ("allergy shots") may help reduce asthma symptoms, and the use of asthma medications, in patients with known allergies. They may also help prevent the development of asthma in children with allergies. Immunotherapy poses some risk for severe allergic reactions, however, especially for children with poorly controlled asthma.

[For detailed information, see In-Depth Report #77: Allergic rhinitis and chronic nasal congestion and In-Depth Report #05: Asthma in children and adolescents.]

Treating and Preventing Medical Conditions that Trigger Asthma

Preventing and Treating Respiratory Infections. Respiratory infections, including the common cold, can act with allergies to worsen asthma. People with asthma should try to minimize their risk for respiratory tract infections. Washing hands is a very simple but effective preventive measure.

Patients with asthma should ask their doctors about the flu vaccine and also whether they should receive the vaccination against pneumococcal pneumonia.

Zanamivir, a new drug used for treating influenza, is considered safe for patients with asthma 12 years of age or older. In one study, patients with asthma who were treated with zanamivir experienced fewer flu symptoms and had improved lung function. [See In-Depth Report #94: Colds and influenza.]

Managing Hormonal-Related Asthma. Women who suspect that menstrual-related changes may influence asthma severity should keep a diary recording their menstrual dates and times of asthma attacks. In some cases, adjusting medications in anticipation of menstruation may help prevent attacks. Some small studies have suggested that hormonal drugs called gonadotropin-releasing hormone (GnRH) analogues may help women with severe premenstrual asthma. Such drugs reduce or suppress estrogen levels, however, and can have severe side effects. More research is needed to determine if the disadvantages outweigh the benefits.

Dietary Factors

Weight Loss. People who have asthma and who are overweight may help reduce asthma symptoms with weight loss.

Fruits, Vegetables, and Whole Grains. Healthy foods are important for lung function. Specific foods that may be important for healthy lungs contain antioxidants (deep green and yellow-orange fruits and vegetables), selenium (fish, red meat, grains, eggs, chicken, liver, garlic), plant chemicals called flavonoids (apples, onions), and magnesium (green leafy vegetables, nuts, whole grains, milk, and meats).

Vitamin D . There may be an association between a lack of vitamin D and asthma. Some research suggests that children are less likely to develop asthma at a young age if their mothers consume a high intake of vitamin D during pregnancy. Vitamin D is available from dietary sources or vitamin supplements.

Fish Oil. Omega-3 fatty acids, found in cold water oily fish and in supplements (preferably DHA-EPA, which are the important compounds in fish oil) have anti-inflammatory effects. Some evidence suggests they may be helpful for people with asthma, although it is weak.

Caffeine. Caffeine has properties that are similar to theophylline, a drug used to treat asthma. A major analysis of studies reported that caffeine improved lung function for up to 4 hours after consumption. (People who are going to have their lung function tested should avoid drinking coffee, tea, or other caffeinated beverages for at least 4 hours beforehand.)

Alcohol. In adults, some research suggests that alcohol intake may influence allergy severity. One study found that as little as one drink a day is enough to worsen dust mite allergies.

Role of Food Allergies. Although 67% of people with asthma believe their symptoms are aggravated by food allergies, studies indicate that this belief may be true in only 5% of cases. The primary suspects are monosodium glutamate, or MSG (found in some canned soups, cheese, and certain vegetables), and sulfites (preservatives in wine and foods that include processed frozen potatoes and tuna). Contrary to what many people believe, dairy products do not appear to worsen asthma symptoms in people who are not already allergic to them.

Exercise

Asthma is no reason to avoid exercise. Historically, about 10% of Olympic athletes have asthma. Some studies indicate that long-term exercise even helps control asthma and reduce hospitalization. Patients should consult their doctors before embarking on any exercise program, however. Uncontrolled asthma can be dangerous and, in rare cases, fatal for athletes, even some with mild asthma. Use of the inhaler is extremely important.

People who enjoy running should probably choose an indoor track to avoid pollutants. Swimming is excellent for people with asthma. Yoga practice, which uses both stretching, breathing, and meditation techniques, may have particular benefits. One study reported that two-thirds of patients who practiced yoga regularly were able to reduce or stop taking their asthma medications.

Exercise-induced asthma is a limited condition that has specific recommendations.

Reducing Stress and Mood Disorders

People with asthma have no higher rate of anxiety or depression than the general population. However, such emotions interact with the effects of asthma and its treatments in important ways:

• Negative emotions can discourage compliance with medication and the ability to cope
• Poor control of asthma symptoms, in turn, increases the risk for negative emotions
• Stress and depression have been associated with more severe symptoms and even an increased risk of fatal asthma attacks

Some evidence suggests that stress reduction techniques, a positive attitude and relaxation techniques can be very helpful in the long-term management of asthma. [See In-Depth Report #31: Stress.]

• Review Date: 3/27/2007
• Reviewed By: Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

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