Wheeze in children under 5 years old

Wheeze in children aged under 5 years old is often triggered by viral infections. The most common cause of wheeze in children depends on their age and other symptoms and risk factors, such as a family history of asthma. 

Common causes include the following:

• Bronchiolitis – this is the most common cause of wheeze in children aged less than one year. Bronchiolitis is a viral infection that affects babies' lungs. Read more about bronchiolitis. 
• Viral upper respiratory tract infection or viral-induced wheeze – this is the most common cause of wheeze in children aged 1–4 years and happens when your child has common cold or a chest infection. Your child is usually well in between the infections. 
• Pre-school asthma – pre-school asthma can be the cause of wheeze in children, especially if there is a family history of asthma or allergies. If your child has been diagnosed with pre-school asthma, it doesn't mean your child will have asthma at school age or older. Regular appointments are needed to assess your child's asthma and treatment. Read more about asthma in children. 
• Bronchiectasis – this is a bacterial infection and can be the cause of wheeze if your child also has a wet-sounding cough that lasts for weeks. Read more about bronchiectasis.
• Foreign body inhalation – this usually causes wheeze that is noticed after a choking episode. 

Your child most likely has asthma if the wheeze happens:

• at night or when they wake up 
• during or after exercise
• when there is a trigger, eg, cold weather, dust, pollen, smoke, grass or certain foods
• when your child is otherwise well.

Asthma is also more likely if your child has eczema or other allergies, or a family history of asthma or allergy. 

Your doctor will ask you about your child's wheeze, including how long they have been wheezing, any triggers and whether it comes and goes. Your doctor will also ask about other symptoms, such as a cough, breathing difficulties, runny nose or sore throat. Your doctor will also listen to your child's lungs.

Sometimes, your doctor will do some blood tests and a chest x-ray to find out the cause of the wheeze, depending on what your doctor thinks is causing it.  

In some cases, the cause of your child's wheeze may not be diagnosed straight away and the diagnosis may change over time. This may require multiple appointments to assess your child's symptoms and response to treatment. 

Treatment depends on what is the likely cause of your child's wheeze. 

Lifestyle changes

• Reduce your child's exposure to cigarette smoke and don't smoke around your child. 
• Keep your home warm and dry. If this is difficult to do, ask your GP or doctor if you are eligible for social support or local housing services. 
• Make sure your child's vaccinations are up to date.
• Make sure everyone in your household washes their hands often to help prevent the spread of infections. 
• Avoid triggers such as grass, pollen, dust or certain food if it is known to cause your child's wheeze.

Medicine

Common medicines that may be prescribed for your children include:

• salbutamol inhalers or relievers
• corticosteroids inhalers or preventers
• oral montelukast
• oral antibiotics for bacterial infections.

Always use an inhaler with a spacer. Spacers make the inhalers much more effective. Read more about spacers. 

You will probably need to visit your GP multiple times to review your child's medicines and response to treatment, especially if your child is diagnosed with pre-school asthma. Your child may outgrow their symptoms and the diagnosis may change. 

About half of children will grow out of their symptoms by school age. 

Asthma New Zealand(external link) provides education, training and support to individuals with asthma/COPD and their families.