About This Page
This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Most common chronic disease of childhood — affects ~10% of UK children
- Diagnosis is clinical in under-5s (spirometry unreliable). In 5–16 year olds: clinical assessment supported by spirometry, peak flow variability, and FeNO
- Stepwise management (BTS/NICE/SIGN NG245): Step 1 SABA as needed → Step 2 add low-dose ICS → Step 3 add LTRA or LABA → Step 4 increase ICS → Step 5 specialist referral
- Inhaler technique and adherence are the most common reasons for poor control — always check before stepping up
- MDI + spacer is first-line inhaler device for children. Under 3s: spacer with face mask
- Acute exacerbation: oxygen, salbutamol via spacer (10 puffs via spacer or nebulised), oral prednisolone 1–2 mg/kg (max 40 mg) for 3 days
Overview
Childhood asthma is characterised by chronic airway inflammation, bronchial hyperresponsiveness, and reversible airflow obstruction. It presents with episodic wheeze, cough (especially nocturnal), chest tightness, and breathlessness. Symptoms are typically triggered by viral infections (most common in young children), exercise, allergens, cold air, and emotional stress. Diagnosis in under 5s is clinical and based on pattern recognition (episodic wheeze, response to bronchodilators, atopic history). In older children, objective tests (spirometry, FeNO, peak flow variability) support the diagnosis.
Epidemiology
Asthma affects approximately 10% of children in the UK — one of the highest prevalences in the world. It is the most common chronic childhood disease and a leading cause of school absence and hospital admission. Risk factors include atopy (eczema, allergic rhinitis, food allergy — the atopic march), family history of asthma/atopy, low birth weight, prematurity, maternal smoking, and air pollution. Many children with preschool wheeze will not go on to have persistent asthma — viral-induced episodic wheeze is common and often resolves by school age.
Clinical Features
Symptoms
Episodic wheeze — worse at night and early morning
Dry cough — especially nocturnal, exercise-induced, or with viral infections
Breathlessness and chest tightness
Symptoms triggered by exercise, cold air, allergens, viral infections
Interval symptoms between episodes (suggests persistent rather than episodic asthma)
Unable to complete sentences, agitated, SpO2 <92% (acute severe)
Silent chest, exhaustion, confusion, cyanosis (life-threatening)
Signs
Expiratory wheeze on auscultation
Hyperinflated chest (chronic poorly controlled asthma)
Harrison sulci (chronic chest wall deformity from respiratory effort)
Signs of atopy: eczema, allergic rhinitis
Tachypnoea, use of accessory muscles, intercostal recession (acute exacerbation)
Silent chest with reduced air entry (life-threatening)
Investigations
First-line
Clinical diagnosis (under 5s)Pattern recognition: episodic symptoms, response to treatment, atopic history. No reliable objective tests in this age group
Spirometry (5+ years)FEV1/FVC ratio <70% (or below lower limit of normal). Reversibility: FEV1 improvement of 12%+ after salbutamol
FeNO (fractional exhaled nitric oxide)FeNO >35 ppb in children supports eosinophilic airway inflammation (asthma). May help guide ICS treatment
Second-line
Peak flow monitoringDiurnal variation >20% over 2–4 weeks supports diagnosis. More useful for monitoring than diagnosis
Allergy testingSkin prick tests or specific IgE — identify relevant allergens (house dust mite, pets, moulds)
Specialist
Bronchial challenge testExercise or methacholine challenge — only in specialist centres if diagnosis unclear
CXRNot routine — consider if diagnostic uncertainty, unilateral wheeze, or poor response to treatment
1
Stepwise management (children 5–16)
- Step 1: SABA as needed (salbutamol via MDI + spacer)
- Step 2: Add low-dose ICS (e.g. beclometasone 100–200 mcg/day or equivalent)
- Step 3: Add LTRA (montelukast) or LABA (salmeterol/formoterol)
- Step 4: Increase ICS to medium dose, consider combination ICS/LABA
- Step 5: High-dose ICS, refer to specialist — consider biologic therapy
- Review regularly: step down when well controlled for 3+ months
2
Under 5s
- Start with SABA as needed for intermittent symptoms
- If symptoms persistent: low-dose ICS
- If insufficient: add LTRA (montelukast)
- MDI + spacer with face mask for children under 3
- Many children with preschool wheeze will outgrow symptoms
3
Acute exacerbation
- Oxygen to maintain SpO2 94–98%
- Salbutamol: 10 puffs via MDI + spacer (or nebulised 2.5–5 mg) — repeat every 20 min if needed
- Oral prednisolone: 1–2 mg/kg/day (max 40 mg) for 3 days
- Add ipratropium bromide (250–500 mcg nebulised) if poor response to salbutamol
- IV magnesium sulphate or aminophylline if life-threatening
- IV salbutamol in HDU/PICU if refractory
4
Key principles
- Always check INHALER TECHNIQUE and ADHERENCE before stepping up treatment
- MDI + spacer is as effective as nebuliser for mild-moderate exacerbations
- Written personalised asthma action plan for every child
- Annual review minimum
Complications
- Acute severe or life-threatening asthma: Respiratory failure, pneumothorax
- Growth suppression: High-dose ICS (usually minimal at standard doses)
- School absence: Leading cause of chronic disease-related school absence
- Fixed airflow obstruction: If poorly controlled over years — airway remodelling
UKMLA Exam Tips
- 1Under 5s: asthma diagnosis is CLINICAL — no reliable spirometry. Treat based on symptoms and response
- 2ALWAYS check inhaler technique before stepping up treatment — most common cause of poor control
- 3MDI + spacer is FIRST-LINE inhaler device for ALL children. Spacer + face mask for under 3s
- 4Acute asthma: SpO2 <92% = severe or life-threatening. Silent chest = life-threatening
- 5Oral prednisolone for 3 days for acute exacerbations — no taper needed in children
- 6BTS/NICE/SIGN stepwise: SABA → ICS → add LTRA or LABA → increase ICS → specialist
- 7Viral-induced wheeze in preschoolers is common and NOT the same as asthma
practicetest your knowledge on childhood asthmaApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — paediatrics and beyond.
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