What are causes of Allergies

Since asthma has a genetic origin and is a disease you may inherit., passed down from generation to generation, the question isn’t really “what causes asthma,” but rather “what causes asthma symptoms to appear?” People with asthma have inflamed airways which are super-sensitive to things which do not bother other people. These things are called “triggers.”

Although asthma triggers vary from person to person based on if you have allergic asthma or non-allergic asthma, some of the most common include:

• Substances that cause allergies (allergens) such as dust mites, pollens, molds, pet dander, and even cockroach droppings. In many people with asthma, the same substances that cause allergy symptoms can also trigger an asthma episode. These allergens may be things that you inhale, such as pollen or dust, or things that you eat, such as shellfish. It is best to avoid or limit your exposure to known allergens in order to prevent asthma symptoms.
• Irritants in the air, including smoke from cigarettes, wood fires, or charcoal grills. Also, strong fumes or odors like household sprays, paint, gasoline, perfumes, and scented soaps. Although people are not actually allergic to these particles, they can aggravate inflamed, sensitive airways. Today most people are aware that smoking can lead to cancer and heart disease. What you may not be aware of, though, is that smoking is also a risk factor for asthma in children, and a common trigger of asthma symptoms for all ages. It may seem obvious that people with asthma should not smoke, but they should also avoid the smoke from others’ cigarettes. This “secondhand” smoke, or “passive smoking,” can trigger asthma symptoms in people with the disease. Studies have shown a clear link between secondhand smoke and asthma, especially in young people. Passive smoking worsens asthma in children and teens and may cause up to 26,000 new cases of asthma each year.
• Respiratory infections such as colds, flu, sore throats, and sinus infections. These are the number one asthma trigger in children.
• Exercise and other activities that make you breathe harder. Exercise—especially in cold air—is a frequent asthma trigger. A form of asthma called exercise-induced asthma is triggered by physical activity. Symptoms of this kind of asthma may not appear until after several minutes of sustained exercise. (When symptoms appear sooner than this, it usually means that the person needs to adjust his or her treatment.) The kind of physical activities that can bring on asthma symptoms include not only exercise, but also laughing, crying, holding one’s breath, and hyperventilating (rapid, shallow breathing). The symptoms of exercise-induced asthma usually go away within a few hours. With proper treatment, a child with exercise-induced asthma does not need to limit his or her overall physical activity.
• Weather such as dry wind, cold air, or sudden changes in weather can sometimes bring on an asthma episode.
• Expressing strong emotions like anger, fear or excitement. When you experience strong emotions, your breathing changes — even if you don’t have asthma. When a person with asthma laughs, yells, or cries hard, natural airway changes may cause wheezing or other asthma symptoms.
• Some medications like aspirin can also be related to episodes in adults who are sensitive to aspirin. Irritants in the environment can also bring on an asthma episode. These irritants may include paint fumes, smog, aerosol sprays and even perfume.

People with asthma react in various ways to these factors. Some react to only a few, others to many. Some people get asthma symptoms only when they are exposed to more than one factor or trigger at the same time. Others have more severe episodes in response to multiple factors or triggers. In addition, asthma episodes do not always occur right after a person is exposed to a trigger. Depending on the type of trigger and how sensitive a person is to it, asthma episodes may be delayed.

Each case of asthma is unique. If you have asthma, it is important to keep track of the factors or triggers that you know provoke asthma episodes. Because the symptoms do not always occur right after exposure, this may take a bit of detective work.

What Happens During an Asthma Episode?

During normal breathing, the airways to the lungs are fully open, allowing air to move in and out freely. But people with asthma have inflamed, super-sensitive airways. Their triggers cause the following airway changes, which in turn cause asthma symptoms:

• The lining of the airways swell and become more inflamed
• Mucous clogs the airways
• Muscles tighten around the airways (bronchospasm)

These changes narrow the airways until breathing becomes difficult and stressful, like trying to breathe through a straw stuffed with cotton.

Why Does My Asthma Act Up at Night?

For reasons we don’t fully understand, uncontrolled asthma — with its underlying inflammation — often acts up at night. It probably has to do with natural body rhythms and changes in your body’s hormones, as well as the fact that some symptoms appear hours after you come in contact with a trigger. The important thing to know about nighttime asthma is that, working with your doctor, you should be able to sleep through the night.

The Role of Heredity in Asthma.

Like baldness, height and eye color, the capacity to have asthma is an inherited characteristic. Yet, although you may be born with the genetic capability to have asthma, asthma symptoms do not automatically appear. We do not know for certain why some people get asthma and others do not. However, doctors doing research have found that certain traits make it more likely that a person will develop asthma.

• Heredity. To some extent, asthma seems to run in families. People whose brothers, sisters or parents have asthma are more likely to develop the illness themselves.
• Atopy. A person is said to have atopy (or to be atopic) when he or she is prone to have allergies. For reasons that are not fully known, some people seem to inherit a tendency to develop allergies. This is not to say that a parent can pass on a specific type of allergy to a child. In other words, it doesn’t mean that if your mother is allergic to bananas, you will be too. But you may develop allergies to something else, like pollen or mold.

In addition, several factors must be present for asthma symptoms to develop:

• Specific genes must be acquired from parents.
• Exposure to allergens or triggers to which you have a genetically programmed response.
• Environmental factors such as quality of air, exposure to irritants, behavioral factors such as smoking, etc.

This information should not substitute for seeking responsible, professional medical care. First created 1995; fully updated 1998; most recently updated 2005. © Asthma and Allergy Foundation of America (AAFA)

Diagnosis

To properly diagnose asthma, you’ll discuss your medical history and have a physical exam with a physician. You may need lung function tests to detect possible limitations in your breathing, and, in some cases, you may need additional tests, such as a chest or sinus X-ray. If you or your child are having problems breathing on a regular basis, don’t wait! Visit a doctor immediately. Knowing what to expect during the diagnostic process and how your doctor arrives at a diagnosis may help.

Common Diagnostic Techniques:

Personal and medical history. Your doctor will ask you questions to get a complete understanding of your symptoms and their possible causes. Bring your notes to help jog your memory. Be ready to answer questions about your family history, the kinds of medicines you take, and your lifestyle at home, school, and work. This includes any current physical complaints. Shortness of breath, wheezing, coughing and a feeling of tightness in your chest may indicate asthma. This also includes all previous medical conditions. A history of allergies or eczema increases the possibility of asthma. Any past or present medical conditions experienced by your parents, brothers or sisters, or children. A family history of asthma, allergies or eczema increases your likelihood of asthma. Your doctors will be interested in any home or occupational exposure to environmental factors that can worsen asthma — for example, pet dander, pollen, dust mites and tobacco smoke.

Overall physical examination. If your doctor suspects asthma, he/she will pay special attention to your ears, eyes, nose, throat, skin, chest and lungs during the physical examination. This exam may include a pulmonary function test to detect how well you exhale air from your lungs. You may also need an X-ray of your lungs or sinuses. A physical exam then allows your doctor to further evaluate your overall health.

Lung function tests. To confirm an asthma diagnosis, your doctor may conduct one or more breathing tests known as lung (pulmonary) function tests. These tests measure many aspects related to your breathing. Common lung function tests used to diagnose asthma include:

Spirometry. During this test — the recommended test for confirming the diagnosis of asthma — you breathe into a mouthpiece that’s connected to a device known as a spirometer. The spirometer records the amount of air you’re able to exhale. You’ll likely be asked to take a deep breath and then exhale forcefully. A spirometer — useful in diagnosing conditions such as asthma — measures the amount of air you’re able to breathe in and out and its rate of flow. The number displayed when breathing into the peak flow meter is a measurement of your ability to force air out of your lungs.

Peak Airflow. This test, one of the simplest lung function tests, uses a peak flow meter — a small, hand-held device that you breathe into — to measure the rate at which you can force air out of your lungs. During the test you breathe in as deeply as you can and then blow into the device as hard and fast as possible. If you’re diagnosed with asthma, you can use a peak flow meter at home to help monitor your condition.

Lung function tests are often done before and after inhaling a medication known as a bronchodilator, which opens your airways. If your lung function improves significantly with use of a bronchodilator, it’s likely you have asthma. Your doctor may also prescribe a trial with asthma medication to see if it improves your lung function.

Trigger tests. If your test results so far are normal, but you’ve been experiencing signs and symptoms of asthma, your doctor may use known asthma triggers to try to provoke a mild reaction. If you don’t have asthma, you won’t react. But if you do have asthma, you likely will. For example, your doctor may have you inhale a substance called methacholine. If you have asthma, inhaling the methacholine will cause your airways to constrict. Your doctor can measure these constrictions using a lung function test. Or, if your doctor suspects you have exercise-induced asthma, he or she may have you take lung function tests before and after exercising to see if there’s a difference.

Additional Tests to Rule Out Other Conditions.

If your doctor suspects you have a condition other than asthma or in addition to asthma, he or she may conduct other tests or assessments, such as a chest X-ray, gastroesophageal reflux test, sinus X-rays, sputum induction and examination, or other. Your doctor may also perform allergy tests. Allergy tests aren’t used to determine whether you have asthma. However, allergy tests can indicate if you have allergies that may be causing or worsening your asthma.

Diagnosing Asthma in Children.

The procedures used to diagnose asthma in children under the age of 5 are slightly different. Children this age usually aren’t given a breathing test. Instead, the doctor asks about certain signs and symptoms and prescribes a bronchodilator if he or she thinks it might be asthma. If the bronchodilator is helpful in reducing your child’s signs and symptoms, that is a sign that your child may have asthma.

SOURCE: This information should not substitute for seeking responsible, professional medical care. First created 1995; fully updated 1998; most recently updated 2005. © Asthma and Allergy Foundation of America (AAFA)

Treatment

Asthma doesn’t have to put major limits on your life. There are many things that you can do to take control of your asthma and minimize its impact on your activities. Because each case of asthma is different, treatment needs to be tailored for each person. One general rule that does apply, though, is removing the things in your environment that you know are factors that make your asthma worse. When these measures are not enough, it may be time to try one of the many medications that are available to control symptoms.

Asthma medications may be either inhaled or in pill form and are divided into two types—quick-relief and long-term control. Quick-relief medicines are used to control the immediate symptoms of an asthma episode. In contrast, long-term control medicines do not provide relief right away, but rather help to lessen the frequency and severity of episodes over time.

Like all medications, asthma treatments often have side effects. These are usually mild and go away on their own. Be sure to ask your doctor about the side effects of the medications you are prescribed and what warning signs should prompt you to contact him or her.

There are two groups of asthma medications:

1. Long term controllers

2. Quick relievers

Long Term Controller Medications

Long term control medications help you keep control of your asthma. The NHLBI Guidelines state that you probably need a long term control medicine if you have symptoms more than twice a week. You will need to take this medicine every day

The anti-inflammatory group of controller medicines is the most important group of long term controller which prevent or reverse inflammation in the airways. This makes the airways less sensitive, and keeps them from reacting as easily to triggers. In short, they actually prevent asthma episodes.

Cromolyn Sodium and Nedocromil Sodium (inhaled) prevent airways from swelling when they come in contact with an asthma trigger. These nonsteroids can also be used to prevent asthma caused by exercise.

Inhaled Corticosteroids (inhaled) prevent and reduce airway swelling and decrease the amount of mucus in the lungs. These are generally safe when taken as directed. They are not the same as anabolic steroids, which some athletes take illegally to build muscles. If you are taking an inhaled anti-inflammatory medicine and you feel your asthma symptoms getting worse, talk with your doctor about continuing or increasing the medicine which you are already taking. You may also need to add an oral corticosteroid or a short-acting beta agonist (bronchodilator) for relief.

Oral Corticosteroids (pills, tablets, liquids) are used as short-term treatment for severe asthma episodes or as long-term therapy for some people with severe asthma. Again, these are not the same as anabolic steroids.

Leukotriene modifiers (tablets) are a new type of long-term control medication. They prevent airway inflammation and swelling, decrease the amount of mucus in the lungs, and open the airways.

The long-actingbronchodilator group is another type of the long term controller medicines which help open the airways over a long period of time. They are taken in addition to anti-inflammatory medicines.

Long-acting beta agonists (inhaled) must be taken with an anti-inflammatory medicine [replaces may be taken] to help control daily symptoms, including nighttime asthma. This type of medicine can also prevent asthma triggered by exercise. Because long-acting beta agonists can not relieve symptoms quickly, they should not be used for an acute attack. You also need a short-acting, inhaled beta agonist for acute symptoms. Long-acting, inhaled beta agonists are not a substitute for anti-inflammatory medicine. You should not decrease or stop taking your anti-inflammatory medicine without talking to your doctor, even if you feel better.

Allergen immunotherapy (shots) has been proven to be anti-inflammatory and this improves the asthmatic condition.

Combined therapy medicine (inhaled) contains both a controller and reliever medicine. This combination of a long-acting bronchodilator and corticosteroid is used for long-term control.

Anti-IgE therapy (injected) is a new treatment for people with moderate or severe allergic asthma. For people with allergic asthma, anti IgE therapy works by helping to reduce the production and diffusion of Immunoglobulin E (IgE), a primary trigger of allergic inflamation in the lungs. It attempts to stop allergic asthma at its root cause instead of just treating asthma symptoms. This drug is not inhaled, but rather injected by your doctor on a regular basis. It does not eliminate your need for other asthma medications, but it can help to reduce your use of them. Due to its significant cost, this form of therapy is currently reserved for moderate to severe cases requiring multiple medications.

Quick Reliever Medications

Quick relief medicines (inhaled and pills) are used to ease the wheezing, coughing, and tightness of the chest that occurs during asthma episodes.

• Short-acting brochodilators (inhaled) are one type of quick relief medicines. They open airways by relaxing muscles that tighten in and around the airways during asthma episodes.
• Short-acting beta agonists (inhaled) relieve asthma symptoms quickly and some prevent asthma caused by exercise. If you use one of these medicines every day, or if you use it more than three times in a single day, your asthma may be getting worse, or you may not be using your inhaler correctly. Talk with your doctor right away about adding or increasing a medication, and about your inhaler technique.
• Oral beta agonists (syrup, tablets and long-acting tablets) syrup may be used for children, while long-acting tablets may be used for nighttime asthma. Oral preparations generally cause more side effects than the inhaled form.
• Theophylline (oral, slow-acting) can be used for persistently symptomatic asthma, and especially to prevent nighttime asthma. Theophylline must remain at a constant level in the blood stream to be effective. Too high a level can be dangerous. Your doctor will do regular blood tests. Sustained release theophylline is not the preferred primary long term control treatment but it is effective when added to other anti-inflammatory medicines to control nighttime symptoms.

This information should not substitute for seeking responsible, professional medical care. First created 1995; fully updated 1998; most recently updated 2005. © Asthma and Allergy Foundation of America (AAFA)

Prevention

For people with asthma, having an “asthma management plan” is the best strategy to prevent symptoms. An asthma management plan is something developed by you and your doctor to help you control your asthma, instead of yourasthma controlling you. An effective plan should allow you to:

• Be active without having asthma symptoms.
• Participate fully in exercise and sports.
• Sleep all night, without asthma symptoms.
• Attend school or work regularly.
• Have the clearest lungs possible.
• Have few or no side-effects from asthma medications.
• Have no emergency visits or stays in the hospital.

Four Parts of Your Asthma Management Plan:

1. Identify and minimize contact with your asthma triggers. Avoiding your triggers is the best way to reduce your need for medication and to prevent asthma episodes. But first, you have to learn what those triggers are. Any time you have an asthma episode, think about where you were and what you were doing in the past day or so. Answer questions like these in a diary or on your calendar:

• Was I making a bed or vacuuming?
• Was I near an animal? Cigarette smoke?
• Did I have a cold or other infection?
• Was I running, playing or exercising?
• Was I upset, excited or tired?

Discuss your notes with your doctor to look for trends. As you identify your triggers, talk about which ones can be avoided, and how to best avoid them. For instance, if you are allergic to dust mites you should put an airtight cover around your pillow and mattress. You may also want to discuss with your physician how immunotherapy might help to prevent allergy symptoms.

2. Take your medications as prescribed. Asthma medicines are usually inhaled through a machine called a nebulizer, through a small device called a metered dose inhaler (also called an inhaler, puffer, or MDI) or through a dry powder inhaler (DPI). For inhalers to work well, you must use them correctly. But over half of all people who use inhalers don’t use them properly. Ask your doctor or nurse to watch you and check your technique. If it is still difficult to use, you have two choices. Ask them to recommend a spacer or holding chamber. This device attaches to the inhaler to make it easier to use and to help more medicine reach the lungs. Or, ask about using a “breath-actuated” inhaler, which automatically releases medicine when you inhale.

Unless your asthma is very mild, chances are you have prescriptions for at least two different medicines. That can be confusing. The more you understand about what those medicines do and why they help, the more likely you are to use them correctly.

Although there are some potential adverse effects from taking asthma medications, the benefit of successfully controlling your asthma outweigh this risk. It is important to discuss each of your asthma medications with your physician to learn more about their effects.

3. Monitor your asthma and recognize early signs that it may be worsening. Asthma episodes almost never occur without warning. Some people feel early symptoms, including: coughing, chest tightness, feeling very tired. But because airways to the lungs narrow slowly, you may not feel symptoms until your airways are badly blocked. The key to controlling your asthma is taking your medicine at the earliest possible sign of worsening.

There is a simple, pocket-sized device called a peak flow meter that can detect narrowing in your airways hours, or even days, before you feel symptoms. You simply blow into it, as instructed in your doctor’s office, to monitor your airways the same way you might use a blood pressure cuff to measure high blood pressure or a thermometer to take your temperature. Peak flow meters come in many shapes and styles. Ask your doctor which is right for you. Your doctor may divide your peak flow numbers into zones (green = safe; yellow = caution; red = emergency) and develop a plan with you. Your peak flow number will help you know:

• Which medicine to take
• How much to take
• When to take it
• When to call your doctor
• When to seek emergency care

The good news is that using your peak flow meter should mean fewer symptoms, fewer calls to the doctor, and fewer hospital visits!

4. Know what to do when your asthma is worsening. If you understand your asthma management plan and follow it, you will know exactly what to do in case of an asthma episode or an emergency. If you have any questions at all, ask your doctor.

SOURCE: This information should not substitute for seeking responsible, professional medical care. First created 1995; fully updated 1998; most recently updated 2005. © Asthma and Allergy Foundation of America (AAFA)