What Is Asthma?
Asthma (AZ-ma) is a chronic (long-term) disease that inflames and narrows your airways. Your airways are tubes that carry air in and out of your lungs. If you have asthma, the inside walls of your airways become sore and swollen. That makes them very sensitive, and they may react strongly to things that you are allergic to or find irritating. When your airways react, they get narrower and your lungs get less air. This can cause wheezing, coughing, chest tightness and trouble breathing, especially early in the morning or at night.
When your asthma symptoms become worse than usual, it's called an asthma attack. In a severe asthma attack, the airways can close so much that your vital organs do not get enough oxygen. People can die from severe asthma attacks.
Asthma is treated with two kinds of medicines: quick-relief medicines to stop asthma symptoms and long-term control medicines to prevent symptoms.
Asthma affects people of all ages, but it most often starts during childhood. In the United States, more than 25 million people are known to have asthma. About 7 million of these people are children.
Overview
To understand asthma, it helps to know how the airways work. The airways are tubes that carry air into and out of your lungs. People who have asthma have inflamed airways. This makes them swollen and very sensitive. They tend to react strongly to certain inhaled substances.
When the airways react, the muscles around them tighten. This narrows the airways, causing less air to flow into the lungs. The swelling also can worsen, making the airways even narrower. Cells in the airways might make more mucus than usual. Mucus is a sticky, thick liquid that can further narrow the airways.
This chain reaction can result in asthma symptoms. Symptoms can happen each time the airways are inflamed.
Figure A shows the location of the lungs and airways in the body. Figure B shows a cross-section of a normal airway. Figure C shows a cross-section of an airway during asthma symptoms.
Sometimes asthma symptoms are mild and go away on their own or after minimal treatment with asthma medicine. Other times, symptoms continue to get worse.
When symptoms get more intense and/or more symptoms occur, you're having an asthma attack. Asthma attacks also are called flareups or exacerbations (eg-zas-er-BA-shuns).
Treating symptoms when you first notice them is important. This will help prevent the symptoms from worsening and causing a severe asthma attack. Severe asthma attacks may require emergency care, and they can be fatal.
Outlook
Asthma has no cure. Even when you feel fine, you still have the disease and it can flare up at any time. However, with today's knowledge and treatments, most people who have asthma are able to manage the disease. They have few, if any, symptoms. They can live normal, active lives and sleep through the night without interruption from asthma.
If you have asthma, you can take an active role in managing the disease. For successful, thorough, and ongoing treatment, build strong partnerships with your doctor and other health care providers.
How Is Asthma Diagnosed?
Your primary care doctor will diagnose asthma based on your medical and family histories, a physical exam, and test results.
Your doctor also will figure out the severity of your asthma—that is, whether it's intermittent, mild, moderate, or severe. The treatment your doctor prescribes will depend on the level of severity.
Your doctor may recommend that you see an asthma specialist if:
- You need special tests to help diagnose asthma
- You've had a life-threatening asthma attack
- You need more than one kind of medicine or higher doses of medicine to control your asthma, or if you have overall problems getting your asthma well controlled
- You're thinking about getting allergy treatments
Medical and Family Histories.
Your doctor may ask about your family history of asthma and allergies. He or she also may ask whether you have asthma symptoms and when and how often they occur.
Let your doctor know whether your symptoms seem to happen only during certain times of the year or in certain places, or if they get worse at night.
Your doctor also may want to know what factors seem to trigger your symptoms or worsen them. For more information about possible asthma triggers, go to"What Are the Signs and Symptoms of Asthma?"
Your doctor may ask you about related health conditions that can interfere with asthma management. These conditions include a runny nose, sinus infections, reflux disease, psychological stress, and sleep apnea.
Physical Exam.
Your doctor will listen to your breathing and look for signs of asthma or allergies. These signs include wheezing, a runny nose or swollen nasal passages, and allergic skin conditions (such as eczema). Keep in mind that you can still have asthma even if you don't have these signs when your doctor examines you.
Diagnostic Tests. Lung Function Test.
Your doctor will use a test called spirometry (spi-ROM-eh-tre) to check how your lungs are working. This test measures how much air you can breathe in and out. It also measures how fast you can blow air out. Your doctor may give you medicine and then retest you to see whether the results have improved. If your test results are lower than normal and improve with the medicine, and if your medical history shows a pattern of asthma symptoms, your doctor will likely diagnose you with asthma.
Other Tests.
Your doctor may recommend other tests if he or she needs more information to make a diagnosis. Other tests may include:
Allergy testing to find out which allergens affect you, if any.
A test to measure how sensitive your airways are. This is called a bronchoprovocation (brong-KO-prav-eh-KA-shun) test.
Using spirometry, this test repeatedly measures your lung function during physical activity or after you receive increasing doses of cold air or a special chemical to breathe in.
A test to show whether you have another condition with symptoms similar to asthma, such as reflux disease, vocal cord dysfunction, or sleep apnea.
A chest x ray or an EKG (electrocardiogram). These tests will help find out whether a foreign object in your airways or another disease might be causing your symptoms.
How Asthma Is Treated and Controlled.
Asthma is a long-term disease that has no cure. The goal of asthma treatment is to control the disease. Good asthma control will:
Prevent chronic and troublesome symptoms, such as coughing and shortness of breath
Reduce your need for quick-relief medicines (see below)
Help you maintain good lung function
Let you maintain your normal activity level and sleep through the night
Prevent asthma attacks that could result in an emergency room visit or hospital stay
To control asthma, partner with your doctor to manage your asthma or your child's asthma. Children aged 10 or older and younger children who are able—should take an active role in their asthma care.
Taking an active role to control your asthma involves:
Working with your doctor to treat other conditions that can interfere with asthma management.
Avoiding things that worsen your asthma (asthma triggers). However, one trigger you should not avoid is physical activity.
Physical activity is an important part of a healthy lifestyle. Talk with your doctor about medicines that can help you stay active.
Working with your doctor and other health care providers to create and follow an asthma action plan.
An asthma action plan gives guidance on taking your medicines properly, avoiding asthma triggers (except physical activity), tracking your level of asthma control, responding to worsening symptoms, and seeking emergency care when needed.
Asthma is treated with two types of medicines: long-term control and quick-relief medicines. Long-term control medicines help reduce airway inflammation and prevent asthma symptoms. Quick-relief, or "rescue," medicines relieve asthma symptoms that may flare up.
Your initial treatment will depend on the severity of your asthma. Followup asthma treatment will depend on how well your asthma action plan is controlling your symptoms and preventing asthma attacks.
Your level of asthma control can vary over time and with changes in your home, school, or work environments. These changes can alter how often you're exposed to the factors that can worsen your asthma.
Your doctor may need to increase your medicine if your asthma doesn't stay under control. On the other hand, if your asthma is well controlled for several months, your doctor may decrease your medicine. These adjustments to your medicine will help you maintain the best control possible with the least amount of medicine necessary.
Asthma treatment for certain groups of people such as children, pregnant women, or those for whom exercise brings on asthma symptoms will be adjusted to meet their special needs.
Follow an Asthma Action Plan
You can work with your doctor to create a personal asthma action plan. The plan will describe your daily treatments, such as which medicines to take and when to take them. The plan also will explain when to call your doctor or go to the emergency room.
Avoid Things That Can Worsen Your Asthma
Many common things (called asthma triggers) can set off or worsen your asthma symptoms. Once you know what these things are, you can take steps to control many of them. (For more information about asthma triggers, go to "What Are the Signs and Symptoms of Asthma?")
For example, exposure to pollens or air pollution might make your asthma worse. If so, try to limit time outdoors when the levels of these substances in the outdoor air are high. If animal fur triggers your asthma symptoms, keep pets with fur out of your home or bedroom.
One possible asthma trigger you shouldnt avoid is physical activity. Physical activity is an important part of a healthy lifestyle. Talk with your doctor about medicines that can help you stay active.
The NHLBI offers many useful tips for controlling asthma triggers. For more information, go to page 2 of NHLBI's "Asthma Action Plan."
If your asthma symptoms are clearly related to allergens, and you can't avoid exposure to those allergens, your doctor may advise you to get allergy shots.
You may need to see a specialist if you're thinking about getting allergy shots. These shots can lessen or prevent your asthma symptoms, but they can't cure your asthma.
Several health conditions can make asthma harder to manage. These conditions include runny nose, sinus infections, reflux disease, psychological stress, andsleep apnea. Your doctor will treat these conditions as well.
Medicines
Your doctor will consider many things when deciding which asthma medicines are best for you. He or she will check to see how well a medicine works for you. Then, he or she will adjust the dose or medicine as needed.
Asthma medicines can be taken in pill form, but most are taken using a device called an inhaler. An inhaler allows the medicine to go directly to your lungs.
Not all inhalers are used the same way. Ask your doctor or another health care provider to show you the right way to use your inhaler. Review the way you use your inhaler at every medical visit.
Long-Term Control Medicines
Most people who have asthma need to take long-term control medicines daily to help prevent symptoms. The most effective long-term medicines reduce airway inflammation, which helps prevent symptoms from starting. These medicines don't give you quick relief from symptoms.
Inhaled Corticosteroids.
Inhaled corticosteroids are the preferred medicine for long-term control of asthma. They're the most effective option for long-term relief of the inflammation and swelling that makes your airways sensitive to certain inhaled substances.
Reducing inflammation helps prevent the chain reaction that causes asthma symptoms. Most people who take these medicines daily find they greatly reduce the severity of symptoms and how often they occur.
Inhaled corticosteroids generally are safe when taken as prescribed. These medicines are different from the illegal anabolic steroids taken by some athletes. Inhaled corticosteroids aren't habit-forming, even if you take them every day for many years.
Like many other medicines, though, inhaled corticosteroids can have side effects. Most doctors agree that the benefits of taking inhaled corticosteroids and preventing asthma attacks far outweigh the risk of side effects.
One common side effect from inhaled corticosteroids is a mouth infection called thrush. You might be able to use a spacer or holding chamber on your inhaler to avoid thrush. These devices attach to your inhaler. They help prevent the medicine from landing in your mouth or on the back of your throat.
Check with your doctor to see whether a spacer or holding chamber should be used with the inhaler you have. Also, work with your health care team if you have any questions about how to use a spacer or holding chamber. Rinsing your mouth out with water after taking inhaled corticosteroids also can lower your risk for thrush.
If you have severe asthma, you may have to take corticosteroid pills or liquid for short periods to get your asthma under control.
If taken for long periods, these medicines raise your risk for cataracts and osteoporosis (OS-te-o-po-RO-sis). A cataract is the clouding of the lens in your eye. Osteoporosis is a disorder that makes your bones weak and more likely to break.
Your doctor may have you add another long-term asthma control medicine so he or she can lower your dose of corticosteroids. Or, your doctor may suggest you take calcium and vitamin D pills to protect your bones.
Other Long-Term Control Medicine.
Cromolyn. This medicine is taken using a device called a nebulizer. As you breathe in, the nebulizer sends a fine mist of medicine to your lungs. Cromolyn helps prevent airway inflammation.
Omalizumab. (anti-IgE). This medicine is given as a shot (injection) one or two times a month. It helps prevent your body from reacting to asthma triggers, such as pollen and dust. Anti-IgE might be used if other asthma medicines have not worked well.
Inhaled long-acting beta2-agonists. These medicines open the airways. They might be added to low-dose inhaled corticosteroids to improve asthma control. Inhaled long-acting beta2-agonists should never be used for long-term asthma control unless they're used with inhaled corticosteroids.
Leukotriene modifiers. These medicines are taken by mouth. They help block the chain reaction that increases inflammation in your airways.
Theophylline. This medicine is taken by mouth. Theophylline helps open the airways.
If your doctor prescribes a long-term control medicine, take it every day to control your asthma. Your asthma symptoms will likely return or get worse if you stop taking your medicine.
Long-term control medicines can have side effects. Talk with your doctor about these side effects and ways to reduce or avoid them.
With some medicines, like theophylline, your doctor will check the level of medicine in your blood. This helps ensure that youre getting enough medicine to relieve your asthma symptoms, but not so much that it causes dangerous side effects.