by Dr Jenny Tang, Paediatrician
SBCC Baby and Child Clinic
Asthma, Lung, Sleep and Allergy Centre
Gleneagles Medical Centre #04-15
What is Bronchial Asthma?
Bronchial Asthma is chronic inflammatory disease of the airways with increased sensitivity to triggers resulting in increased swelling of the airways, mucous production and tightening of the air passages with difficulty in breathing. Children with bronchial asthma often have other associated allergies e.g. food allergies, eczema and allergic rhinitis and these may occur at various times in childhood (Fig 1). Children with a family history of asthma or other allergic disorders are more likely to suffer from asthma.
How common is it?
Asthma is the most common chronic disease, affecting children in many parts of the world including Singapore. It affects about 20% of school going children in Singapore and is one of the most common conditions requiring emergency treatment and hospital admission in childhood. A significant number of children with Bronchial Asthma also report frequent school absences due to asthma as well as exercise limitation and inability to participate in physical exercise.
What are the common symptoms?
The common symptoms are wheezing, cough, shortness of breath and chest tightness.
Wheezing is a high pitch whistling sound that occurs when a child breathes out. It may not be present in all children with asthma.
Cough often accompanies wheezing or may be the only complaint in some children. Cough is generally most troublesome at night or early in the morning or may be provoked by activity or other known triggers, e.g. allergens.
Shortness of breath is usually associated with wheezing and cough and usually suggests a more severe episode of asthma. It may be preceded by an upper respiratory tract infection or occur after exercise.
Chest tightness may be a complaint of older children particularly after exercise.
What are the common triggers?
- Viral respiratory tract infections are the most common triggers in young children. These infections generally precede an episode of asthma by 1-2 days and asthma symptoms may persist for 1-2 weeks after.
- Exercise is a common trigger in children with uncontrolled asthma. Symptoms usually occur several minutes after exercise or may occur many hours later in the same night.
- Allergens are common triggers of asthma symptoms. Locally, house dust mites, animals/pets, cockroach and mould are some of the more common inhaled allergens. Food as a cause of isolated airway allergy symptoms is not common.
- Irritants in the air can aggravate pre-existing asthma. Tobacco smoke, air pollution, strong smells and fumes can provoke symptoms of asthma.
- Other substances that may trigger symptoms in some children with asthma include emotions (e.g. stress, excitement), weather changes, changes in temperature, drugs (e.g. Voltaran, Ibuprofen), chemicals (e.g. artificial colourings and preservatives)
How do doctors confirm the diagnosis of Bronchial Asthma?
A good history and physical examination is the most important part of diagnosis. Some investigations that may be useful include:
- Chest X-ray and other imaging: This may be useful to exclude chest or heart problems as a cause of chronic cough, breathlessness, or in severe asthma to exclude complications or associated chest infection.
- Lung function tests: These are safe and simple tests that can be done in co-operative children 2 years or older. These tests include spirometry, measurement of airway resistance by impulse oscillometry and exhaled nitric oxide. These tests help to assess for baseline impairment of lung function, if any, and allows objective tracking of lung function.
- Exercise challenge test: This is useful to confirm exercise induced asthma in older children who have activity induced symptoms.
- Allergy tests: These can be done in children of any age if indicated and can be done as a skin prick test or a blood test. Allergy tests are useful to confirm sensitisation to environmental allergens (e.g. house dust mites, cat, dog) as a possible trigger of asthma symptoms.
What medicines are used to treat Bronchial Asthma?
Medications required for treatment of Bronchial Asthma will vary depending on the age of the patient, type of asthma, the severity, triggers and the presence of other medical conditions. The child’s previous response to medication and preference for device use are also considered.
Medicines used for treatment of bronchial asthma fall into two groups: Controller therapy and Rescue therapy.
Controller medications are used to treat the underlying inflammation in bronchial asthma and include steroidal e.g. fluticasone, budesonide and non-steroidal medications e.g. montelukast.
Rescue medications are used to reverse the acute symptoms of asthma, which is due to airway narrowing and include salbutamol, terbutaline and ipratropium bromide.
For most children with chronic asthma, medications are given via the inhaled route i.e. Metered dose aerosol, dry powder inhaler or neubuliser. Use of a spacer with a metered dose inhaler in younger children allows optimal delivery of medications to the airways. Oral steroids or intravenous medications may be required with more severe attacks of asthma.
Sublingual immunotherapy if used for treatment of associated allergic rhinitis may also improve asthma control and reduce medications used
If an allergen is identified as a trigger for asthma symptoms then allergen avoidance measures are useful e.g. Avoidance of cat exposure in cat allergy or integrated measures to reduce house dust mite levels in the bedroom.
Monitoring and Follow up
As asthma is a chronic disease, close monitoring and follow up is important especially if the child is on controller medications. These medications may be stepped up or stepped down depending on the control of symptoms and pulmonary function test results. The Asthma Control Test (ACT) is an easy way of assessing if a child’s asthma is well controlled. A score of more than 20 suggests uncontrolled asthma and a consultation with paediatrician with experience in treatment of Bronchial Asthma is recommended. Compliance with the medication plan and advice of the doctor will optimise treatment outcomes.
What is the long-term outcome of a child with Bronchial Asthma?
Two of three children with asthma are attack-free by adolescence. This is more likely if they have mild asthma. Of those who continue to have symptoms, these become less frequent and less severe with time. In some, there may be an attack free period of several years before symptoms return.
Most children with well-managed Bronchial Asthma can have a normal quality of life with no restrictions on physical activities and diet.