Childhood Asthma

What is asthma in children?

Asthma is a disease which primarily affects the bronchial tubes in the lungs, called the airways. Children affected by asthma typically experience breathing difficulties due to the inflammation of the airways.

Asthma can cause acute discomfort – such as an asthma attack – and can have a debilitating effect on the child’s overall health, including symptoms like tiredness, depleted strength and recurrent coughing. The most common signs of asthma include:

  • Wheezing
  • Chest pain
  • Shortness of breath

These symptoms may be present every day or only during an asthma attack.

Asthma affects around 6.2 million children in the U.S.[1] If a child experiences recurrent coughing, wheezing, tightness or pain in their chest or shortness of breath, it is important to consult a doctor, as one or more of these symptoms may indicate childhood-onset asthma.

When the respiratory system is functioning normally, as in a healthy child, the airways allow oxygen to pass into the lungs, which supply it to the rest of the body via the bloodstream. The airways of an asthmatic child are hypersensitive and will react by becoming inflamed and swollen when certain physical and environmental triggers enter the airways. This swelling makes it difficult for sufficient air to pass through the airways to the lungs, causing the child to experience breathing difficulties.

The potential impact of childhood-onset asthma on a child’s quality of life and long-term health can be significantly minimised by identifying appropriate treatment to bring their symptoms under control. Children with untreated asthma tire more easily after exercise than their peers and are prone to coughing and wheezing.

With effective treatment, it is possible to reduce the symptoms of asthma, so that asthmatic children can carry out their day-to-day activities as normal, including participating in exercise and outdoor activities.


Children who have parents who have asthma and children who have allergies are more likely to develop asthma. Children who are exposed to irritating fumes, such as cigarette smoke and air pollution are also more likely to develop asthma than other children.


Children are affected by asthma more commonly than adults. Asthma in children usually starts to develop in early childhood. Asthmatic children often present symptoms at under five years of age. Despite the presence of asthma-like symptoms, it can be difficult to diagnose asthma in infants and young children, as their lungs may not be developed sufficiently to carry out certain tests.

One of the first signs that a child might be affected by asthma is an involuntary whistling sound which accompanies their breathing. This is commonly known as “wheezing.” Typically, wheezing is especially prominent when the child exhales.

Other possible signs and symptoms of childhood-onset asthma include:

  • Chest pain
  • Chest tightness
  • Depleted stamina after play or exercise
  • Diminished energy throughout the day
  • Difficulty drawing breath
  • Recurrent coughing, typically at night
  • Retractions (involuntary pulling in of the chest which occurs as a result of laboured breathing)
  • Shortness of breath


When a child experiences an asthma attack, their airways are reacting to specific triggers in the environment.[2] The absolute cause of asthma is still unknown, but there are many different triggers (stimuli) which are associated with bringing on asthma attacks or aggravating asthmatic symptoms.

Triggers affect every child differently. Children may appear to outgrow, or become immune to, certain triggers. Equally, they may develop new sensitivities as they mature. The intensity of their adverse reactions to specific triggers may also increase or decrease.

Here are some environmental and physical triggers that are known to worsen the symptoms of asthma in children:


  • Airborne irritants (such as pet dander) and pollutants (such as scented cleaning products)
  • Weather conditions, especially changes in temperature or humidity


  • Allergies
  • Emotional extremes such as stress, anger or nervousness
  • Exercise
  • Gastroesophageal reflux
  • In infants, feeding
  • Negative reactions to pharmaceutical medications such as painkillers
  • Respiratory infections such as colds and/or flu

Skin or food allergies can cause asthma symptoms to occur in some children. This is called allergy-induced asthma or allergic asthma.

Allergy-induced asthma

Allergy-induced asthma is the most common type of asthma. Allergic asthmatic children are simultaneously affected by allergies and asthma. It is possible to confuse an allergic reaction, such as hay fever, with a flare-up of asthma. It can be difficult to determine whether a child’s symptoms relate to either condition, or to a combination of both. This is further complicated by the fact that it is possible for both reactions to be stimulated by the same trigger.

Allergens which commonly trigger allergic asthmatic reactions in children include:

  • Dander from pets
  • Dust mites
  • House dust
  • Pollen

If a child appears to be affected by asthmatic symptoms, allergic reactions or a combination of the two, it is advisable to visit your health care provider or an allergist, who will be able to help identify the principal triggers, and suggest further stimuli to be avoided.

An allergist may also decide to prescribe medications against allergy symptoms, such as antihistamines. These will need to be factored into the child’s overall treatment plan, which will involve measures to manage their asthma. These may include asthma medications, immunology programmes and/or the use of a nebulizer, depending on the severity of the child’s condition and how often they experience a flare-up (see “Treatment” for more information).


It is not always possible to identify the cause of asthma in children, and a child may develop the condition with no apparent triggers. The main possible causes of asthma in children are:

  • Genetic predisposition: Children with a family history of asthma, eczema, hives and/or allergic rhinitis develop asthma more commonly than those without.
  • Environmental factors: Exposure to air pollutants, including cigarette smoke and potential triggers of asthma, including dust mites, pollen and pet dander, may cause children to develop asthma.
  • Infections: Children may develop asthma as a result of certain types of infections that affect the airways, including viral infections such as the common cold.

Risk factors

Some children are at greater risk of developing asthma than others. Risk factors for developing asthma include:

  • A family history of asthma and related conditions such as eczema
  • A medical history of allergic reactions, including food and pet allergies, skin reactions and hay fever
  • Living in an urban area (where there is greater exposure to pollution)
  • Regular exposure to potential triggers of asthma such as cigarette smoke and pet dander
  • Obesity
  • Other respiratory conditions, including sinusitis (inflamed sinuses) and/or a chronic blocked nose (rhinitis)
  • Gastroesophageal reflux disease (GERD)

Before puberty, boys are at greater risk of developing asthma than girls; the biological reasons for this are not yet understood.[3]


Each child experiences asthma differently, and a child may not exhibit all of the symptoms or respond to all the triggers listed. Within individual children, asthma symptoms and their severity may change. It is usual for the doctor to consider a range of possible causes for the child’s symptoms, in order to eliminate other conditions before offering a definitive diagnosis of asthma.

Non-allergic conditions that typically cause asthma-like symptoms include:

  • Aspiration (when pieces of food or other small items accidentally pass into the airway)
  • Pulmonary Aspergillosis (a fungal infection of the lung)
  • Respiratory tract infections such as bronchiolitis and respiratory syncytial virus (RSV)
  • Rhinitis (runny, stuffy nose)
  • Sinusitis
  • Vocal cord dysfunction
  • Acid reflux or gastroesophageal reflux disease (GERD)
  • Airway abnormalities caused by such as an esophageal disorder (where acid from the stomach triggers a reaction that inflames the airways) or neuromuscular respiratory diseases

Many of these conditions commonly co-occur with asthma. A diagnosis of asthma in a child therefore requires the doctor to determine whether the child’s symptoms are purely asthmatic, caused by a condition other than asthma, or whether the child has developed another condition in addition to asthma.

Diagnostic tests

A variety of tests are available to help diagnose asthma in children, including lung function tests and allergy skin tests. These tests usually work best for children of five years and older.

Diagnosing asthma in children of 5 years and older

To diagnose asthma in children of 5 years and older, doctors tend to use the same tests that are used to identify the disease in adults. The main tests used to identify asthma are:

  • Lung function tests: Lung function tests (spirometry) are primary tests used to measure how much air the child can exhale and how quickly. They involve using a device called a spirometer, attached to a mouthpiece by a cable. [4] To determine the severity of the asthma diagnosis, the child’s lung function is usually measured during three levels of activity: after taking asthma medication, after exercising and at rest. Lung function tests employ flow volume loops to measure how quickly the child can inhale, and their maximum intake of breath in one inhalation. This helps detect obstruction of air in the neck, such as vocal cord paralysis or dysfunction- which helps to identify any non-asthmatic conditions that may be a correct or additional diagnosis.
  • Allergy skin tests: When a child is diagnosed with asthma, and the doctor suspects that they may be affected by allergic asthma, allergy skin tests may be used in addition to the tests for asthma to test for possible triggers which may be causing the symptoms. The skin is pricked, and solutions containing extracts of common allergy-causing substances are applied, such as animal dander, mold or dust mites. The child is then observed for signs of an allergic reaction.
  • Methacholine challenge test (MCT): The Methacholine challenge test (MCT) is used to diagnose mild or intermittent (occurring at irregular intervals) asthma. If lung function tests do not result in the child’s asthma diagnosis, a doctor may order a methacholine challenge test. During this test, the child inhales increasing amounts of a mist of methacholine before and after spirometry. Methacholine is a drug that stimulates the nervous system and causes wheezing and shortness of breath.
  • Body plethysmography: In some cases, a body plethysmography test may be carried out in addition to the diagnostic tests above. In this test, a child will breathe in and out in an instrument called a body box. The body box is airtight, and breathing in and out of it causes changes to the air pressure inside the box.

Medical professionals can monitor the air pressure inside the box to add many details to their understanding of how well a child’s respiratory system is performing. This test can be used to measure factors including the volume of air present in the lungs after breathing normally, the specific airway resistance (how much the respiratory tract resists airflow when a person breathes in and out) of the lungs and their total lung capacity.[5]

Diagnosing asthma in children under 5 years of age

It is often very hard for doctors to provide a conclusive diagnosis of asthma in children under 5 years of age, as their lungs are not sufficiently developed to accurately carry out lung function tests. Many other conditions such as rhinitis, sinusitis, and respiratory tract infections, such as bronchitis, have the same symptoms as asthma. For this reason, doctors often opt to observe a child’s symptoms over a longer period with regular check-ups, until it is possible to provide an asthma diagnosis.


Inhaled medications that target airway inflammation are used to improve symptoms. These medications are sometimes taken regularly and sometimes just at times when the child is wheezing or breathless. At times of severe asthma symptoms, children might need oxygen or other emergency treatments to help them breathe.


Taking care to prevent the spread of colds or the flu in the home and community can help prevent episodes of asthma. Avoiding things that make the asthma worse (allergies, areas of air pollution, exercise) can help with managing symptoms. Not allowing cigarette smoking in the home or near children can help prevent asthma or reduce the number of asthma attacks.

Other names for childhood asthma

  • Asthma in children
  • Bronchial asthma in children
  • Pediatric asthma

  1. Asthma facts.” United States Environmental Protection Agency. May 2017. Accessed: 09 February 2018.

  2. Asthma Information." ACAAI Public Website. March 20, 2017. Accessed June 17, 2017.

  3. Gender differences in asthma development and progression.” Gender medicine. 2007. Accessed: 09 February 2018.

  4. "Spirometry." NHS Choices. July 27, 2016. Accessed June 14, 2017.

  5. Whole-body plethysmography in suspected asthma.” Dtsch Arztebl Int. June 2015. Accessed: 09 February 2018.