How do I know if my child has asthma?

Asthma is an all-too common problem in adults and children alike. It can range from mild to serious, and this can be a particular worry for parents of young children who exhibit coughing, wheezing, or trouble breathing. Leading paediatrician Dr Michael Markiewicz explains how to diagnose asthma in children, what can trigger it, and more…

How do I know if my child has asthma?

Diagnosing asthma is both easy and difficult. Many children go undiagnosed for considerable periods of time.

The mainstay of diagnosing asthma in children under the age of five is by history rather than by doing tests.

There are two kinds of asthma to consider.

Children who suffer “acute asthma attacks” are reasonably easy to diagnose. The children will be coughing and wheezing and having difficulty breathing. They will usually respond to bronchodilators. The triggering factors can be an upper respiratory infection or exposure to an allergen. Exercise too can be a trigger.

Much more difficult to diagnose is chronic asthma, which I will concentrate on.

The most important part of the diagnosis is a cough. This is usually nocturnal and it is persistent for at least ten days; often it is present for 8-10 weeks. Often, children with chronic asthma do not have any wheezing. The persistent cough can cause them to be tired during the day due to disturbed sleep patterns.

Family history is relevant and having one parent with asthma gives you a 2.6 x likelihood of the child having asthma with the odds ratio doubling if both parents have asthma.

What are the top asthma triggers?

The most common triggering factors of asthma are:

• Viral URTI (upper respiratory tract infection)
• Some allergens, such as house dust mites
• Environmental factors, such as smoking or damp wet homes with mildew, paint, etc.
• Animals (such as cats)
• Weather changes can be triggers, although this is more likely to affect acute asthma attacks than children with chronic asthma.
• Stress (again, this is more likely to cause an acute attack).

How do you test a child for asthma?

Testing children for asthma is age-dependent.

Under 5 years of age, testing is unreliable and not usually done.

Chest X-rays are not helpful and should not be done except in exceptional circumstances.

Allergy testing may be helpful if one considers an allergen as a possible trigger.

If we consider a possible diagnosis of chronic asthma then treatment may offer a diagnostic clue if treatment is successful.

The treatment options suggested by the British Thoracic Society Guidelines differ from the American guidelines.

My preference in my practice is to use the American version as dictated by the National Heart and Lung Institute. The main difference is that the American guidelines suggest the early use of montelukast, whereas the English ones suggest early use of inhaled steroids. I find in my practice that it is worthwhile using montelukast, which is a non-steroidal anti-inflammatory medication. In a significant number of children, this works and is a good indicator of a diagnosis.

In children over 5 years, we can perform respiratory function tests looking at reversibility. In addition, we can measure exhaled nitric oxide, which can give a clue about the presence of airway inflammation. These tests are useful in making a diagnosis.

Allergy testing in older children is also useful to this end.

Can a child outgrow asthma?

There are no good figures for this answer. The range quoted is that between 30-80% of children who have initial asthma may outgrow it in childhood, but will redevelop it later in life. There are some studies which have shown that children who are no longer wheezy may still have ongoing airway inflammation.