General information about asthma
What is asthma?
Asthma is a disease of the airways in the lungs. It’s caused by chronic inflammation and, to a varying degree, results in over-sensitiviness, airflow limitation and other symptoms of breathing problems: recurrent attacks of wheezing, breathlessness, chest tightness and coughing. An attack can go away by itself for the time being, or as a result of treatment.
The condition is not constant, but changes over time and every child with asthma has good or better days (or periods) and bad or worse ones. If asthma is properly treated, there can be long periods without symptoms or attacks.
What is inflammation in the airways?
Inflammation is a way for the body to protect itself, for example against infections or other triggers. The result is often redness and swollen tissue.
Airway inflammation is a reaction in the cells lining our airways and in the underlying tissue.
How does airway inflammation affect my child’s asthma?
When airway inflammation causes asthma symptoms, it is because the airflow to and from the lungs becomes limited. This limited airflow is caused by:
* increased inflammation;
* tightening of the muscles that surround the airways (also called bronchoconstriction), which makes the airways narrower;
* the over-production of mucus (which can “plug up” the airways);
* changes in the walls of the airways (leading to a chronic condition or permanent damage).
Chronically inflamed airways are “hyper-responsive”, which means that they react faster, stronger and more drastically to various triggers such as allergens (from pollen and pets), viruses, dust, smoke and stress.
How do they react? They become narrower, so that airflow may become more limited and cause wheezing and coughing to become worse.
The condition is not constant, but changes over time and every child with asthma has good days and bad days.
Who gets asthma?
Asthma runs in families, which means that a child is more likely to develop asthma if someone in the family already has it.
Children with eczema and food allergy are at greater risk to develop asthma during childhood.
Allergy to pollen or pets also increases the risk of getting asthma.
Tobacco smoke or air pollution can cause asthma symptoms.
Asthma is common; around one out of every ten children in the Western World develops asthma.
At what age does asthma start?
Asthma can start at any age, although about half of all people with asthma have had their first symptoms by the age of 10. Many children with asthma have had their first asthma attack before the age of 6.
What causes asthma?
The causes of asthma are not fully understood. It’s probably a mixture of hereditary factors (those you are born with) and environmental factors - but how these factors work together is still largely unknown.
Asthma during early childhood is often caused by viral infections in the upper and lower airways. Most of these young children will have symptom-free periods between the infections, and more than half of will be free from asthma symptoms later in life. It is questioned whether this kind of asthma is different from asthma later in childhood, often caused by allergy.
Allergy is the most common cause of asthma in childhood. Allergens from pets and house dust mites are the most common causes. Allergy to pollen and moulds can also cause allergic asthma.
Tobacco smoke and air pollution can cause asthma symptoms.
Is asthma a chronic disease?
Yes, asthma is a chronic disease with chronic inflammation of the airways. This inflammation is sometimes weaker or stronger, but is present in most patients even in symptom-free periods.
An exception is asthma symptoms caused only by virus infections during infancy. But some of these children will continue to react with asthma symptoms during infections, when exposed to triggers or if they become allergic.
Untreated asthma will lead to repeated attacks of asthma symptoms. An attack can go away by itself for the time being, or as a result of treatment. With proper treatment, there can be long periods without symptoms and attacks.
The symptoms change over time and every child with asthma has good or better days (or periods) and bad or worse ones. It’s important to remember that if asthma is properly treated, there can be long periods without symptoms or attacks.
Revision date: July 6, 2011
Last revised: by Jorge P. Ribeiro, MD