What causes asthma?

Although asthma can occur in people of any age, even in infants, most children with the disease can only be confidently diagnosed by five years of age.
Asthma seems to be more common in boys than in girls in early childhood and it’s more common in blacks and in city-dwellers than in whites and those who reside in suburban and rural areas.

How does an episode happen?

 When one breathes in, air travels through the nose and/or mouth through the windpipe (trachea) and then enters a series of smaller tubes that branch off from the windpipes. These branched tubes are the bronchi, and they further subdivide into smaller tubes called the bronchioles.

 It is in the bronchi and bronchioles that asthma has its main effects. When the airways come into contact with a trigger – something the body reacts to, the lining and other cells inside the bronchi and bronchioles becomes inflamed.

 At the same time, the muscles on the outside of the airways tighten up, causing them to narrow. Then fluid is released into the bronchioles as part of the inflammation process making them swollen. The breathing passages are narrowed still more and breathing becomes very difficult.

It is important to note that everyone's airways constrict somewhat in response to irritating substances. But in a person with asthma, the airways are hyper reactive. This means that their airways overreact to things that would just be minor irritants in people without asthma.

What causes asthma?

To some extent, asthma seems to run in families - implicating genetic underpinnings. Children whose brothers, sisters, or parents have asthma are more likely to develop the illness themselves.

If both parents have asthma, the risk is greater than if only one parent has it. For some reason, the risk appears to be greater if the mother has asthma than if the father does.

Certain types of allergies can increase the risk of developing asthma. A person is said to have atrophy (or to be atopic) when he or she is prone to have allergies. This tendency is passed on from the person's parents.

It is not the same as inheriting a specific type of allergy. Rather, it is merely the tendency to develop allergies. In other words, both the child and the parent might be allergic to something, but not necessarily to the same thing.

Substances in the environment that cause allergies — things like dust mites, mould or pollen — are known as allergens.

Atrophy causes the body to respond to allergens by producing a certain type of antibodies called immunoglobulin E antibodies. One way to test a person for allergies is to perform skin tests with extracts of the allergens or do blood tests for the antibodies to these allergens.

It is important to be aware of the things in the environment that tend to make asthma worse. These factors vary from person to person.  Some allergens (substances that cause allergies) are more likely to trigger an asthma attack.

For instance, babies in particular may have food allergies that can bring on asthma symptoms. Some of the foods to which children are commonly allergic are eggs, cow's milk, and wheat, soybean products, and tree nuts, peanut and shell fishes.

 A baby with food allergy may manifest as diarrhoea and vomiting. The child is likely to have a runny nose, a wet cough, and itchy, flaky skin.

In toddlers, common allergens that trigger asthma include house dust mites, moulds and animal hair. In older children, pollen may be a trigger, but indoor allergens and moulds are more likely to be a cause of asthma.

Some types of viral infections can also trigger asthma. Two of the most likely culprits are respiratory syncytial virus (RSV) and Para influenza virus.

 The latter affects the respiratory tract in children, sometimes causing bronchitis (inflammation of the bronchi) or pneumonia (inflammation of the lining inside the lungs).

 RSV can cause diseases of the bronchial system known as bronchopneumonia and bronchiolitis. A young child who has wheezing with bronchiolitis is likely to develop asthma later in life.

Tobacco smoke is also a risk factor for asthma in children and a common trigger of asthma for all ages. People with asthma should not only smoke, but should also avoid the smoke from others' cigarettes.

This “passive smoking," can trigger asthma symptoms in people with the disease. Other irritants in the environment can also bring on an asthma attack. These irritants may include paint fumes, smog, aerosol sprays and even perfume.

 Exertion — especially in cold air — is a frequent asthma trigger. A form of asthma called exercise-induced asthma is triggered by physical exertion. Symptoms of this kind of asthma may not appear until several minutes of sustained exertion.

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).  Cold air, wind, rain and sudden changes in the weather can sometimes bring on an asthma attack. 

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

How does asthma manifest?

Common symptoms of asthma include the following:

•  Wheezing is a high-pitched, whistling sound made during an asthma attack. Not all people who wheeze have asthma, and not all those who have asthma wheeze.

In fact, if asthma is really severe, there may not be enough movement of air through a person's airways to produce this sound.

•  Chronic cough, especially at night and after exercise or exposure to cold air, can be a symptom of asthma.

•  Shortness of breath, especially during exercise, is another possible sign. All of us get out of breath when running and jumping, but most resume normal breathing very quickly afterward.

People with asthma do not resume normal breathing during an attack.

•  Tightness in the chest is a symptom that an older children and adults can describe. Others may just have an uncomfortable feeling in the chest.

Treatment

In mild cases of asthma, the symptoms usually subside on their own. Most people with asthma, though, need medication to control or prevent the episodes. The need for medication is based on how often asthma attacks occur and how severe the attacks are.

With the treatments available today, most people with asthma can do almost everything that people without the disease can do.

Because each case of asthma is different, treatment needs to be tailored for each person. One general rule that does apply, though, is removing known triggers from the environment.

When possible, keeping down levels of dust mites, mould, animal dander and cockroach debris in the house — especially in the child's bedroom — can be helpful.

When these measures are not enough, it may be time to try one of the many medications that are available to control symptoms.

New guidelines from the National Institute of Health advise treating asthma with a "stepwise" approach. This means using the lowest dose of medication that is effective and "stepping up" the dose and the frequency with which it is taken if the asthma gets worse.

When the asthma gets under control, the medicines are then reduced - “stepped down."

Asthma medications may be either inhaled or in pill form. These medications are divided into two types — quick-relief and long-term control.

 The first group (quick relief) is used to relieve the immediate symptoms of an asthma attack. The second group (long-term control) does not provide relief right away, but over time these medications help to lessen the frequency and severity of attacks.

Like any medication, asthma treatments often have side effects.

Quick-relief medications are medications that provide immediate relief of asthma symptoms by relaxing the muscles around the airways, making breathing easier. They begin to work within minutes after they are used and their effects may last for up to six hours.

Most of the quick-relief medications are inhaled through a pocket-sized device (inhaler) and in the children under six years, through a spacer device that the child can easily learn to use when he or she feels the symptoms.

These medications can also be used before exercise to help ward off asthma symptoms.

Long-term control medications. The long list of long-term control medications for asthma includes both oral and inhaled medications.

Unlike the quick-relief medications, long-term medicines do not provide quick relief in the midst of an asthma episode. Rather, they work over the long term to reduce the frequency and severity of attacks.

Most of these medications take several weeks of regular use to achieve their full effect and all work only when they are taken consistently.
 However the most important treatment modality is educating people about the condition.

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A member of Paediatric Society of Ghana