Asthma and Allergies

Asthma is a disease of the branches of the windpipe (bronchial tubes), which carry air in and out of the lungs. There are several different types of asthma.

Allergic asthma is a type of asthma that is triggered by an allergy (for example, pollen or mold spores). According to the American Academy of Allergy, Asthma and Immunology, half of the 20 million Americans with asthma have allergic asthma.

Air is normally taken into the body through the nose and windpipe and into the bronchial tubes. At the end of the tubes are tiny air sacs called alveoli that deliver fresh air (oxygen) to the blood. The air sacs also collect stale air (carbon dioxide), which is exhaled out of the body. During normal breathing, the bands of muscle surrounding the airways are relaxed and air moves freely. But during an asthma episode or "attack," there are three main changes that stop air from moving freely into the airways:

• The bands of muscle that surround the airways tighten, causing them to narrow in what is called a "bronchospasm."
• The lining of the airways becomes swollen, or inflamed.
• The cells that line the airways produce more mucus, which is thicker than normal.

The narrowed airway traps stale air (carbon dioxide) in the lungs. As a result, people with asthma feel they cannot get enough air into the lungs. All of these changes make breathing difficult.

What Are the Most Common Symptoms of Asthma?

Symptoms strike when your airways undergo the three changes described above. Some people can go a long time between asthma episodes while others have some symptoms every day. Common symptoms of asthma include:

• Frequent cough, especially at night
• Shortness of breath
• Wheezing
• Chest tightness, pain, or pressure

Not every person with asthma has the same symptoms in the same way. You may not have all of these symptoms, or you may have different symptoms at different times. Your symptoms may also vary from one asthma episode to the next. Symptoms may be mild during one asthma episode and severe during another.

Mild asthma episodes are generally more common. Usually, the airways open up within a few minutes to a few hours. Severe episodes are less common, but last longer and require immediate medical help. It is important to recognize and treat even mild symptoms to help you prevent severe episodes and keep asthma in control.

If you suffer from allergies and asthma, a reaction to any offending allergy-causing substance can worsen asthma symptoms.

What Are the Early Warning Signs of an Asthma Attack?

Early warning signs are changes that happen just before or at the very beginning of an asthma attack. These changes start before the more prominent symptoms of asthma and are the earliest signs that a person's asthma is worsening. Early warning signs and symptoms include:

• Frequent cough, especially at night
• Losing your breath easily or shortness of breath
• Feeling very tired or weak when exercising, in addition to wheezing, coughing, or shortness of breath
• Decreases or changes in peak expiratory flow, a measurement of how fast air comes out of your lungs when you exhale forcefully
• Signs of a cold or other upper respiratory infections, or allergies
• Difficulty sleeping

If you have any of these symptoms, seek treatment as soon as possible to prevent experiencing a severe asthma attack.

Who Gets Asthma?

Anyone can get asthma, although it tends to run in families. An estimated 20 million adults and children in the U.S. have asthma. For unknown reasons, this disease is becoming more widespread.

What Causes Asthma?

Asthma is a problem in the airways, but the exact cause is unknown. The airways in a person with asthma are very sensitive and react to many things, which are referred to as "triggers." Coming into contact with these triggers often produces asthma symptoms.

There are many kinds of asthma triggers. Reactions are different for each person and vary from time to time. Some people have many triggers while others have none that they can identify. One of the most important aspects of asthma control is avoiding triggers when possible.

Common asthma triggers include:

• Infections: colds, flu, sinus infections
• Exercise: very common in children*
• Weather: cold air, changes in temperature
• Tobacco smoke and air pollution
• Allergens: substances that cause allergic reactions in the lungs, including dust mites, pollens, pets, mold spores, foods and cockroaches
• Dust or items causing dust
• Strong odors from chemical products
• Strong emotions: things such as anxiety, crying, yelling or laughing hard
• Medicines: including aspirin, ibuprofen and beta blocker medications used to treat conditions including high blood pressure, migraines or glaucoma

*Note: Exercise is one trigger you should not avoid. With a good treatment plan, you can exercise as long and as much as desired, except during an asthma attack.

How Is Asthma Diagnosed?

Doctors can use a number of tests to diagnose asthma. First, the doctor reviews your medical history, symptoms, and general health. Next, tests may be given to check the general condition of your lungs, including:

• Chest X-ray in which a picture of the lungs is taken.
• Pulmonary function test (spirometry): A test that measures how well the lungs can take in air and how well this air can be exhaled (lung function). The Also measured is how efficiently the lungs can transfer oxygen into the blood. The patient blows into a tube placed between the lips.
• Peak expiratory flow: A test that measures the maximum amount of air that can be exhaled from the lungs. The patient blows into a hand-held device called a peak flow meter.
• Methacholine challenge test: A test used to see if the airways are sensitive to methacholine, an irritant that tightens the airways.
• Other tests, such as allergy tests, blood tests, sinus X-rays and other imaging scans, and esophageal (throat) pH tests may also be ordered. These tests can help your doctor find out if other conditions are affecting your asthma.

How Is Asthma Treated?

By avoiding asthma triggers, taking medicines and carefully monitoring daily asthma symptoms, asthma attacks can be avoided or at least limited. Proper use of medicines is the basis of good asthma control. Medicines used to treat asthma include bronchodilators, anti-inflammatories and leukotriene modifiers.

Bronchodilators

These medicines relax the muscle bands that tighten around the airways. They rapidly open the airways, letting more air in and out of the lungs and improving breathing.

Bronchodilators also help clear mucus from the lungs. As the airways open, the mucus moves more freely and can be coughed out more easily. In the short-acting form, bronchodilators relieve or stop asthma symptoms and are very helpful during an asthma attack. The three main types of bronchodilators are beta2 agonists, anticholinergics and theophylline.

Anti-inflammatories

These medicines, which include inhaled corticosteroids such as Azmacort, Flovent and Beclovent, reduce swelling and mucus production in the airways. As a result, airways are less sensitive and less likely to react to triggers. Anti-inflammatories are taken daily for several weeks before they begin to control asthma. These medicines lead to fewer symptoms, better airflow, less sensitive airways, less airway damage and fewer asthma episodes. If taken every day, they can control or prevent asthma symptoms.

Another type of anti-inflammatory asthma medication is cromolyn sodium. This medicine is a mast cell stabilizer, which means that it helps prevent the release of asthma-inducing chemicals from cells in the body known as mast cells. It is commonly used in children and for exercise-induced asthma.

Leukotriene modifiers

Leukotriene modifiers are newer asthma drugs and include the drugs Accolate and Singulair. Leukotrienes are chemicals that occur naturally in our bodies and cause tightening of airway muscles and production of mucus and fluid. Leukotriene modifiers work by limiting these reactions, improving airflow and reducing asthma symptoms. They are taken as pills (or as oral granules that can be mixed with food) one or two times a day and decrease the need for other asthma medications. The most common side effects are headache and nausea. Leukotriene modifiers may interact with other drugs, like Coumadin and theophylline. Inform your doctor about any medications you are taking.

How Are Asthma Medicines Taken?

Many asthma medicines are taken using a device called a "metered dose inhaler", a small aerosol canister in a plastic container that releases a burst of medication when pressed down from the top.

Several medicines can also be taken as a powder inhaled through the mouth from a device called a dry powder inhaler. Asthma medicines can also be taken as vapors, pills, liquids and shots.

What Else Should I Do to Help Control My Asthma?

It's also important to keep track of how well your lungs are functioning. Asthma symptoms are monitored using a peak flow meter -- a device that measures the maximum amount of air that comes out of your lungs when you exhale forcefully. This measurement is called peak expiratory flow (PEF) and is calculated in liters per minute.

The meter can alert you to changes in the airways that may be a sign of worsening asthma. By taking daily peak flow readings you can learn when to adjust medications to keep asthma under good control. Your doctor can also use this information to adjust your treatment plan.

Can Asthma Be Cured?

There's no cure for asthma, but it can be treated and controlled. In most cases, people with asthma can live free of symptoms by following their treatment plan.

What Research Is Being Done on Asthma?

There are many people studying asthma and how it can be controlled. A recent study by the National Institute of Allergy and Infectious Diseases found that cockroaches are a leading asthma trigger among children in inner-city areas. Recent studies have also focused on asthma in the elderly and pregnant women.