Asthma and wheezing in babies

by | Babies and Pregnancy, Respiratory Health

Coughing and wheezing are common symptoms in infants and babies. However, in babies, these symptoms are often due to airway conditions other than asthma.

Asthma is a condition in which the airways are over-reactive, resulting in airway narrowing, restricting airflow. In babies younger than 12 months, the airways are already small so it doesn’t take much inflammation or narrowing to cause symptoms. A recurring wheeze can be the first indication that a baby might have asthma. However, wheezing and coughing, particularly in the first year of life, are often not due to asthma.

Most babies who have recurrent wheezing grow out of it by early childhood, and do not go on to have asthma. Asthma is more likely to be the cause of wheezing in children who continue to wheeze beyond 3 years of age.

Risk factors for asthma in babies and young children

Several things may suggest to your doctor that asthma is likely, including:

  • several symptoms, for example cough, shortness of breath and wheeze;
  • frequently recurring symptoms;
  • symptoms that tend to be worse at night and early in the morning;
  • symptoms that occur when the baby does not have a cold;
  • symptoms that are triggered by cold air, exposure to pets, emotions, laughter and exercise;
  • a history of allergic conditions, such as eczema;
  • close relatives having a history of asthma or allergic conditions such as eczema or hay fever; and
  • improvement when given an inhaled asthma medicine.

Asthma diagnosis

A definite diagnosis of asthma may not be possible until your child is old enough for lung function tests. Generally children younger than 4 to 5 years cannot perform lung function tests properly. If a child is too young to have lung function tests, a diagnosis of asthma may still be made by the doctor, based on the child’s history, symptoms and physical examination. However, most children aged 6 years and older can perform lung function tests reliably.

Other causes of coughing and wheezing in babies

It is not always easy for doctors to tell whether a baby has asthma or another condition causing similar symptoms, especially before 12 months of age. There are many other causes of wheezing in babies apart from asthma that must be considered.


Bronchiolitis is a common condition of babies under 6 months old. Most cases occur between late autumn and early spring. Caused by a virus, initial symptoms include a runny nose, cough and fever. The baby’s cough often worsens and they may also start wheezing and breathing quickly. Bronchiolitis generally lasts about 10 days; the cough, however, may last for weeks. In some infants, especially young babies, bronchiolitis can be severe, occasionally requiring hospitalisation.

Other conditions

Other conditions apart from asthma and bronchiolitis that can cause cough and/or wheeze in babies younger than 12 months include:

  • respiratory viruses; and
  • croup, an infection mainly affecting the larynx (voice box) and trachea (windpipe), causing the baby to have a harsh, barking cough.

And, less commonly:

  • cystic fibrosis;
  • lung development problems, including those due to a premature birth;
  • milk aspiration (milk flowing into the airways instead of the stomach during feeding);
  • a foreign body in the airways; and
  • heart problems.

Treating asthma in infants

If your baby needs asthma medicine, your doctor will explain how to give this to the baby. Asthma medicines are likely to be inhaled (breathed in) rather than swallowed.

For babies and very young children, the inhaler is attached to a small spacer chamber, which is attached to a face mask. The inhaler is pressed by the parent or doctor to dispense the medicine into the holding chamber, and the baby’s own breathing then draws in the medicine from the spacer via the face mask.

If your baby has been treated with asthma medicine and gets better on this treatment your doctor may wish you to continue with this approach. You will need to have your baby checked regularly by the doctor as changes in treatment are likely as your baby grows.

If your baby continues to cough or wheeze despite a trial of asthma medicine, this may mean that your baby needs to be reassessed as another condition may be causing their symptoms.

If your baby has been diagnosed with asthma, your doctor will teach you how to know when your baby’s asthma is getting worse, and will give you an asthma action plan that tells you which medicine to give if this happens, and when to contact your doctor or a hospital.

The asthma action plan is an important part of keeping your baby’s asthma well controlled. It is also important to make sure your baby has regular check-ups and is given any prescribed medicine regularly.

Prevention of asthma in babies

Asthma seems to be a product of the complex interplay between a baby’s genes and a baby’s environment, both before and after birth, especially in the first year of life.

The most important thing you can do to help prevent asthma is not smoke while pregnant or after your baby is born. Tell your partner, other family members and friends not to smoke inside the house or anywhere near the baby.

In terms of other measures that are sometimes suggested to reduce the risk of a child developing asthma, the National Asthma Council has provided the following information.

  • Breast feeding should be encouraged as it has many benefits for your baby. However, there is not enough evidence that breast feeding protects against asthma.
  • If you are not breast feeding, partially-hydrolysed milk formulas may be recommended for allergy prevention in infants at risk of developing allergies. However, there is currently insufficient evidence that these formulas reduce the risk of asthma.
  • There is insufficient evidence to recommend taking vitamin supplements or fish oil during pregnancy to reduce the risk of asthma in babies.
  • Taking probiotics or prebiotics during late pregnancy and while breast feeding (or giving probiotics to formula-fed babies) does not seem to prevent asthma.
  • Avoiding potential allergens in the diet (e.g. eggs, milk, nuts and shellfish) while pregnant or breast feeding, or omitting these foods from an older baby’s diet, does not appear to prevent asthma.
  • Avoiding house dust mites alone does not seem to prevent asthma in young children.
  • Current evidence suggests that having a pet in the house neither protects against asthma nor increases the risk of asthma in children.

It is recommended that you do not go on a restriction diet during pregnancy or when breast feeding — unless you need to do so for a definite food allergy that you have had diagnosed — as this has not been shown to reduce the risk of your baby developing asthma, and it may lead to you eating a diet that is poor for both you and your developing baby. Always check with your doctor or dietitian before making changes to your diet during pregnancy or breast feeding or to your baby’s diet.