Asthma: Causes, Symptoms, Diagnosis, Treatment and Prevention

Asthma: Causes, Symptoms, Diagnosis, Treatment and Prevention


What is asthma?


Asthma (AZ-ma) is a chronic (long-term) lung disease that inflames and narrows the airways. Asthma causes recurring periods of wheezing (a whistling sound when you breathe), chest tightness, shortness of breath, and coughing. The coughing often occurs at night or early in the morning.

Asthma Causes, Symptoms, Diagnosis, Treatment and Prevention

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.

Bronchial tubes that are chronically inflamed may become overly sensitive to allergens (specific triggers) or irritants (nonspecific triggers). The airways may become "twitchy" and remain in a state of heightened sensitivity. This is called "bronchial hyperreactivity" (BHR). It is likely that there is a spectrum of bronchial hyperreactivity in all individuals. However, it is clear that asthmatics and allergic individuals (without apparent asthma) have a greater degree of bronchial hyperreactivity than nonasthmatic and nonallergic people. In sensitive individuals, the bronchial tubes are more likely to swell and constrict when exposed to triggers such as allergens, tobacco smoke, or exercise. Amongst asthmatics, some may have mild BHR and no symptoms while others may have severe BHR and chronic symptoms.

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.

Causes Of Asthma


No one really knows what causes asthma. What we do know is that asthma is a chronic inflammatory disease of the airways. The causes of asthma symptoms can vary for different people. Still, one thing is consistent with asthma: when airways come into contact with an asthma trigger, the airways become inflamed, narrow, and fill with mucus.

Asthma Causes, Symptoms, Diagnosis, Treatment and Prevention
Causes and triggers of Asthma

Factors that are known to increase the likelihood of developing asthma include:


  • A family history of asthma or other related allergic conditions (known as 'atopic conditions'), such as eczema, food allergy or hay fever
  • Developing another atopic condition such as a food allergy
  • Having bronchiolitis as a child (a common lung infection among children)
  • Being exposed to tobacco smoke as a child, particularly if your mother smoked during pregnancy
  • Being born prematurely (especially if you needed a ventilator)
  • Being born with a low birth weight (less than 2kg).

The symptoms of asthma can have a range of triggers:


  • Infections of the airways and chest
  • Allergens, such as pollen, dust mites, animal fur or feathers
  • Airborne irritants, such as cigarette smoke, chemical fumes and pollution
  • Some painkillers, such as aspirin and ibuprofen
  • Emotional factors, such as stress or laughing
  • Foods containing sulphites, such as concentrated fruit juice, jam, prawns and many processed or pre-cooked meals
  • Weather conditions, such as sudden change in temperature, cold air, windy days, poor air quality and hot, humid days
  • Indoor  conditions, such as mould or damp, house dust mites and chemicals in carpets and flooring materials
  • Exercise.

How Do Triggers Make Asthma Worse?


In people with asthma, the airways are always inflamed and very sensitive, so they react to a variety of external factors, or "triggers." Coming into contact with these triggers is what causes the symptoms of asthma -- the airways tighten and become inflamed, mucus blocks the airways and results in a worsening of asthma symptoms. An asthma attack can begin immediately after exposure to a trigger or several days or even weeks later.

There are many causes of asthma. Reactions to the causes of asthma are different for each person and vary from time to time. Certain causes of asthma may be harmless to some people but contribute to inflammation in others. Some people have many causes of their asthma while others have no identifiable ones. Recognizing and avoiding the specific causes of asthma, when possible, is an important way to control asthma. Keep in mind, however, that the best way to control is with asthma treatment and asthma drugs.

How Can I Tell What Causes and Triggers My Asthma?


Determining what factors were present when your asthma symptoms started is the first step to identifying the causes of your asthma. Although there are many different asthma triggers, you may not react to all of them. Some people have only one cause or trigger, while others have many causes.

Many causes of asthma can be identified through a history of reaction and skin or blood testing. Your doctor may also recommend using a device called a peak flow meter. The peak flow meter measures how much and how quickly air is exhaled from the lungs. It can alert you to changes in your breathing and the onset of asthma symptoms.

Ask your asthma doctor if using a peak flow meter would be helpful to you as you narrow down the causes of your asthma.

Who Is at Risk for Asthma?


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.

Young children who often wheeze and have respiratory infections—as well as certain other risk factors—are at highest risk of developing asthma that continues beyond 6 years of age. The other risk factors include having allergies, eczema (an allergic skin condition), or parents who have asthma.

Among children, more boys have asthma than girls. But among adults, the disease affects men and women equally. It's not clear whether or how sex and sex hormones play a role in causing asthma.


Some people develop asthma because of contact with certain chemical irritants or industrial dusts in the workplace. This type of asthma is called occupational asthma.

Symptoms And Signs Of Asthma


The symptoms of asthma vary from person to person and in any individual from time to time. It is important to remember that many of these symptoms can be subtle and similar to those seen in other conditions. All of the symptoms mentioned below can be present in other respiratory, and sometimes, in heart conditions. This potential confusion makes identifying the settings in which the symptoms occur and diagnostic testing very important in recognizing this disorder.

Asthma Causes, Symptoms, Diagnosis, Treatment and Prevention

Most people with asthma have attacks separated by symptom-free periods. Some people have long-term shortness of breath with episodes of increased shortness of breath. Either wheezing or a cough may be the main symptom.

Asthma attacks can last for minutes to days, and can become dangerous if the airflow is severely restricted.

Symptoms of asthma include:


  • Cough with or without sputum (phlegm) production
  • Pulling in of the skin between the ribs when breathing (intercostal retractions)
  • Shortness of breath that gets worse with exercise or activity
  • Wheezing, which:
  1. Comes in episodes with symptom-free periods in between
  2. May be worse at night or in early morning
  3. May go away on its own
  4. Gets better when using drugs that open the airways (bronchodilators)
  5. Gets worse when breathing in cold air
  6. Gets worse with exercise
  7. Gets worse with heartburn (reflux)
  8. Usually begins suddenly

Emergency symptoms:


  • Bluish color to the lips and face
  • Decreased level of alertness, such as severe drowsiness or confusion, during an asthma attack
  • Extreme difficulty breathing
  • Rapid pulse
  • Severe anxiety due to shortness of breath
  • Sweating

Other symptoms that may occur with this disease:


  • Abnormal breathing pattern --breathing out takes more than twice as long as breathing in
  • Breathing temporarily stops
  • Chest pain
  • Tightness in the chest

What Causes Asthma Symptoms To Occur?


Many things can trigger or worsen asthma symptoms. Your doctor will help you find out which things (called triggers) may cause your asthma to flare up if you come in contact with them. Triggers can include:

  • Allergens from dust, animal fur, cockroaches, mold, and pollens from trees, grasses, and flowers
  • Irritants such as cigarette smoke, air pollution, chemicals or dust in the workplace, compounds in home decor products, and sprays (such as hairspray)
  • Medicines such as aspirin or other nonsteroidal anti-inflammatory drugs and nonselective beta-blockers
  • Sulfites in foods and drinks
  • Viral upper respiratory infections, such as colds
  • Physical activity, including exercise
Other health conditions can make asthma harder to manage. Examples of these conditions include a runny nose, sinus infections, reflux disease, psychological stress, and sleep apnea. These conditions should be treated as part of an overall asthma care plan.

Asthma is different for each person. Some of the triggers listed above may not affect you. Other triggers that do affect you might not be on the list. Talk with your doctor about the things that seem to make your asthma worse.

Treatment for Asthma


You and your doctor should work together as a team to develop and carry out a plan for eliminating asthma triggers and monitoring symptoms.

Asthma Causes, Symptoms, Diagnosis, Treatment and Prevention


There are two basic kinds of medication for treating asthma:
  • Control drugs to prevent attacks
  • Quick-relief (rescue) drugs for use during attacks
Each type is described in more detail below.

Control drugs to prevent attacks


Long-term control drugs for asthma are used to prevent symptoms in people with moderate to severe asthma. You must take them every day for them to work. Take them even when you feel okay.
  • Inhaled steroids prevent symptoms by preventing airway swelling. These work very well and are almost always the first choice.
  • Long-acting beta-agonist inhalers also help prevent asthma symptoms. These drugs should be used together with an inhaled steroid drug. It may be easier to use an inhaler that contains both drugs.
Other control drugs that may be used are:

  • Leukotriene inhibitors (such as Singulair and Accolate)
  • Omalizumab (Xolair)
  • Cromolyn sodium (Intal) or nedocromil sodium (Tilade)

Quick-relief (rescue) drugs work fast to control asthma symptoms:


  • You take them when you are coughing, wheezing, having trouble breathing, or having an asthma attack. They are also called "rescue" drugs.
  • They also can be used just before exercising to help prevent asthma symptoms that are caused by exercise.
  • Tell your doctor if you are using quick-relief medicines twice a week or more to control your asthma symptoms. Your asthma may not be under control, and your doctor may need to change your dose of daily control drugs.

Quick-relief drugs include:


  • Short-acting bronchodilators (inhalers), such as Proventil, Ventolin, and Xopenex
  • Your doctor might prescribe oral steroids (corticosteroids) when you have an asthma attack that is not going away. These are medicines that you take by mouth as pills, capsules, or liquid. Plan ahead. Make sure you do not run out of these medications.
A severe asthma attack requires a check-up by a doctor. You may also need a hospital stay, oxygen, breathing assistance, and medications given through a vein (IV).

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 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 shouldn’t 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.

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.

Asthma Causes, Symptoms, Diagnosis, Treatment and Prevention

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, and sleep apnea. Your doctor will treat these conditions as well.


Asthma Care At Home


  • Know the asthma symptoms to watch out for
  • Know how to take your peak flow reading and what it means
  • Know which triggers make your asthma worse and what to do when this happens.
Asthma action plans are written documents for anyone with asthma. An asthma action plan should include:
  • A plan for taking asthma medications when your condition is stable
  • A list of asthma triggers and how to avoid them
  • How to recognize when your asthma is getting worse, and when to call your doctor or nurse
A peak flow meter is a simple device to measure how quickly you can move air out of your lungs.
  • It can help you see if an attack is coming, sometimes even before any symptoms appear. Peak flow measurements can help show when medication is needed, or other action needs to be taken.
  • Peak flow values of 50% - 80% of a specific person's best results are a sign of a moderate asthma attack, while values below 50% are a sign of a severe attack.

Asthma Treatment for Special Groups


The treatments described above generally apply to all people who have asthma. However, some aspects of treatment differ for people in certain age groups and those who have special needs.

Asthma Treatment for Children


It's hard to diagnose asthma in children younger than 5 years. Thus, it's hard to know whether young children who wheeze or have other asthma symptoms will benefit from long-term control medicines. (Quick-relief medicines tend to relieve wheezing in young children whether they have asthma or not.)

Doctors will treat infants and young children who have asthma symptoms with long-term control medicines if, after assessing a child, they feel that the symptoms are persistent and likely to continue after 6 years of age.

Inhaled corticosteroids are the preferred treatment for young children. Montelukast and cromolyn are other options. Treatment might be given for a trial period of 1 month to 6 weeks. Treatment usually is stopped if benefits aren't seen during that time and the doctor and parents are confident the medicine was used properly.

Inhaled corticosteroids can possibly slow the growth of children of all ages. Slowed growth usually is apparent in the first several months of treatment, is generally small, and doesn't get worse over time. Poorly controlled asthma also may reduce a child's growth rate.

Many experts think the benefits of inhaled corticosteroids for children who need them to control their asthma far outweigh the risk of slowed growth.

Asthma Treatment for Older Adults


Doctors may need to adjust asthma treatment for older adults who take certain other medicines, such as beta blockers, aspirin and other pain relievers, and anti-inflammatory medicines. These medicines can prevent asthma medicines from working well and may worsen asthma symptoms.

Be sure to tell your doctor about all of the medicines you take, including over-the-counter medicines.

Asthma Causes, Symptoms, Diagnosis, Treatment and Prevention

Older adults may develop weak bones from using inhaled corticosteroids, especially at high doses. Talk with your doctor about taking calcium and vitamin D pills, as well as other ways to help keep your bones strong.

Asthma Treatment for Pregnant Women


Pregnant women who have asthma need to control the disease to ensure a good supply of oxygen to their babies. Poor asthma control increases the risk that a baby will be born early and have a low birth weight. Poor asthma control can even risk the baby's life.

Studies show that it's safer to take asthma medicines while pregnant than to risk having an asthma attack.

Talk with your doctor if you have asthma and are pregnant or planning a pregnancy. Your level of asthma control may get better or it may get worse while you're pregnant. Your health care team will check your asthma control often and adjust your treatment as needed.

How Can Asthma Be Prevented?


You can’t prevent asthma. However, you can take steps to control the disease and prevent its symptoms. For example:

  • Learn about your asthma and ways to control it.
  • Follow your written asthma action plan. (For a sample plan, go to the National Heart, Lung, and Blood Institute's "Asthma Action Plan.")
  • Use medicines as your doctor prescribes.
  • Identify and try to avoid things that make your asthma worse (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.
  • Keep track of your asthma symptoms and level of control.
  • Get regular checkups for your asthma.

More reference for Asthma: