Asthma in Children

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Asthma is a chronic inflammatory condition of the airways characterised by variable and recurring symptoms, airflow obstruction, bronchial hyper-responsiveness, and underlying inflammation. In children, it is one of the most common long-term conditions and can vary in severity from mild to life-threatening. Asthma typically presents with episodes of wheezing, breathlessness, chest tightness, and coughing.

Aetiology

Asthma in children is multifactorial, often triggered by genetic predisposition and environmental factors. Common aetiologies include:

• Genetic predisposition: Family history of asthma, allergies, or atopy increases the likelihood of asthma in children.
• Environmental allergens: Dust mites, pollen, animal dander, and mould can trigger asthma symptoms.
• Viral respiratory infections: Respiratory syncytial virus (RSV) or rhinovirus can lead to asthma exacerbations in children.
• Air pollution: Exposure to environmental pollutants, such as tobacco smoke or exhaust fumes, is a known trigger.

Pathophysiology

Asthma involves chronic inflammation of the airways, leading to bronchial hyper-responsiveness and intermittent airway obstruction. Key features include:

• Inflammation of the bronchial walls causing narrowing of the airways.
• Increased mucus production, leading to obstruction of airflow.
• Bronchoconstriction (tightening of the airway muscles) triggered by allergens, exercise, or cold air.
• If untreated, chronic inflammation can lead to airway remodelling, reducing long-term lung function.

Risk Factors

• Family history of asthma or atopy.
• Exposure to environmental triggers such as allergens (dust mites, pollen, mould).
• Frequent respiratory infections, particularly in early childhood.
• Passive smoking or exposure to tobacco smoke.
• Obesity may contribute to increased asthma symptoms.
• Premature birth or low birth weight.

Signs and Symptoms

The signs and symptoms of asthma in children are often variable and can worsen at night or during physical activity. Common symptoms include:

• Wheezing (high-pitched whistling sound during breathing).
• Shortness of breath, particularly during physical activity or at night.
• Chest tightness or discomfort.
• Coughing, especially at night or after exercise.
• Episodes of increased work of breathing, such as rapid breathing or nasal flaring in younger children.

Investigations

Diagnosis of asthma in children is largely clinical, based on history and physical examination, but certain investigations may help confirm the diagnosis:

• Peak expiratory flow (PEF): Measurement of the maximum speed of expiration.
• Spirometry: Used to measure lung function and assess airflow obstruction (usually in children over 5).
• Fractional exhaled nitric oxide (FeNO): A marker of airway inflammation used in older children.
• Allergy testing: Skin prick tests or specific IgE blood tests to identify allergic triggers.
• Chest X-ray: May be performed to rule out other conditions, but is not routinely used in diagnosing asthma.

Management

Management of asthma in children follows a stepwise approach, aiming to control symptoms and reduce the risk of exacerbations. Treatment is tailored to the severity of the condition.

Under 5 Years:

Step 1: Very Low Dose Inhaled Corticosteroids (ICS)

• Clenil Modulite® 50 pMDI: 2 puffs twice daily (BD).
• As needed rescue inhaler: **Salbutamol (SABA)** 2 puffs.

Step 2: Add Leukotriene Receptor Antagonist (LRTA)

• Montelukast 4mg in the evening for children aged 6 months to 5 years.
• Monitor response after 4-8 weeks and discontinue if not effective.

Step 3: Low Dose ICS

• Clenil Modulite® 100 pMDI: 2 puffs BD.
• Referral to a specialist if still uncontrolled.

6-11 Years:

Step 1: Very Low Dose ICS

• Clenil Modulite® 50 pMDI: 2 puffs BD.
• As needed rescue inhaler: **Salbutamol (SABA)** 2 puffs.

Step 2: Low Dose ICS

• Clenil Modulite® 100 pMDI: 2 puffs BD.

Step 3: Low Dose ICS + LABA (Long-acting Beta-Agonist)

• Seretide Evohaler 50/25 pMDI: 2 puffs BD.

Over 12 Years:

Management for older children aligns closely with that of adults but with adjustments for dosing and suitability.

Step 1: Low Dose ICS + LABA

• Symbicort Turbohaler® 200/6: 1 puff BD.

References

1. South East London Asthma Guidelines (2024).
2. NHS (2023) Asthma in Children. Available at: https://www.nhs.uk/conditions/asthma/
3. National Institute for Health and Care Excellence (NICE) (2024). Asthma: Diagnosis and Monitoring. Available at: NICE