Childhood asthma diagnosis and stepwise treatment

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Asthma combines chronic airway inflammation, hyperresponsiveness and variable bronchoconstriction. Phenotypes differ by age; preschool viral wheeze often resolves, while atopy and interval symptoms increase persistence probability.

Diagnosis begins with pattern: genuine polyphonic expiratory wheeze, variability, triggers, night waking, exercise limitation, atopy and family history. Isolated cough without wheeze or airflow evidence is rarely sufficient.

FeNO reflects type-2 airway inflammation and steroid responsiveness, not airflow itself. Atopy can raise it and current ICS can lower it, so interpretation stays within the full algorithm.

Spirometry must meet quality standards and be compared with age, sex and height reference values. Bronchodilator reversibility demonstrates variability, while normal testing between symptoms may need repetition.

Asthma control includes daytime symptoms, night waking, activity and reliever need; risk includes prior attacks, oral steroids, admission, low lung function, SABA overuse and treatment gaps.

Inhaled corticosteroid prevents attacks by suppressing inflammation. A SABA opens smooth muscle rapidly but does not treat inflammation; frequent reliance signals risk and demands review.

Spacer choice and technique determine lung dose. Young children use a compatible valved spacer with mask until a reliable mouthpiece seal; one puff at a time with repeated tidal breaths is taught and observed.

MART uses the same ICS/formoterol inhaler for maintenance and symptom relief, increasing anti-inflammatory treatment when symptoms rise. The child must understand the regimen and device licensing.

Montelukast may help some children but response is variable. Families need explicit counselling to stop and seek advice for new nightmares, mood, behaviour or suicidal symptoms.

Comorbid rhinitis, obesity, sleep apnoea, dysfunctional breathing, anxiety and inducible laryngeal obstruction can worsen symptoms without steroid-responsive bronchoconstriction.

Every review is preventive: vaccination, smoke-free environment, school inhaler access, exercise participation and an action plan reduce avoidable attacks.

Specialist referral is needed for diagnostic doubt, severe attacks, preschool recurrent hospital care, poor control on moderate therapy or suspected biologic eligibility.

Key points

Asthma is variable respiratory symptoms with variable expiratory airflow limitation. Typical patterns are wheeze, breathlessness, chest tightness or cough that vary over time and with exercise, viral infection, allergens, cold air or night.
Do not diagnose from symptoms alone in a child able to test. Record objective evidence and the basis for diagnosis; examination may be normal between episodes.
Age 5–16 first objective test: FeNO. A value at least 35 ppb confirms asthma in a compatible history; inhaled corticosteroid can suppress FeNO and make testing falsely normal.
If FeNO is not raised or unavailable, perform spirometry with bronchodilator reversibility. An FEV1 rise at least 12% from baseline, or at least 10% of predicted normal FEV1, supports diagnosis.
If spirometry is delayed, twice-daily peak flow for 2 weeks supports diagnosis when amplitude percentage mean variability is at least 20%. Persistent doubt requires allergy/eosinophil assessment then paediatric specialist review and possible bronchial challenge.
Under age 5 there is no reliable reference test. Use a clinical phenotype, exclude alternatives, trial treatment when indicated and retry objective testing every 6–12 months once feasible.
Before every step up, check diagnosis, inhaler and spacer technique, adherence, dose actually dispensed, smoke or vape exposure, allergen triggers and comorbidity.
Age 5–11 first-line maintenance is twice-daily paediatric low-dose inhaled corticosteroid plus short-acting beta2 agonist as needed.
If uncontrolled at age 5–11 and able to use it, consider paediatric low-dose MART, then moderate-dose MART. Licensing is device and age specific; current NICE notes only one 100/6 microgram budesonide/formoterol dry-powder inhaler licensed for MART age 6–11 in November 2025.
If unable to manage MART, consider an 8–12 week montelukast trial, stopping if ineffective; then step to low-dose and moderate-dose ICS/LABA plus SABA. Discuss the MHRA warning about neuropsychiatric reactions.
Under 5 with interval symptoms or severe recurrent episodes: trial twice-daily low-dose ICS plus SABA for 8–12 weeks. Stop and reassess response; add an LTRA trial only after technique, adherence and environment review, and refer when uncontrolled.
Give a personalised written action plan, spacer education and regular review. Step down after sustained control, one change at a time, while retaining an anti-inflammatory strategy and monitoring attacks.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Genetic and atopic susceptibility

Polygenic tendency, eczema, allergic rhinitis and sensitisation increase persistent type-2 airway inflammation and asthma probability. within the child-specific clinical phenotype.

Environmental exposure

Viral infections, tobacco smoke, vaping aerosol, allergens, air pollution, cold air and exercise trigger symptoms in susceptible airways.

Preschool developmental phenotype

Small airway calibre and frequent viral infections create recurrent wheeze that may resolve or evolve into school-age asthma.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Airway inflammation
Eosinophilic and other inflammatory pathways produce mucosal oedema, mucus and heightened sensitivity to otherwise minor stimuli.
2
Reversible smooth-muscle constriction
Trigger-induced bronchial contraction narrows expiratory airways and usually improves spontaneously or after beta2 agonist. during progression of the respiratory disorder.
3
Variable airflow limitation
Changing calibre creates episodic wheeze, reduced FEV1 and peak-flow variability rather than fixed obstruction. during progression of the respiratory disorder.
4
Airway remodelling
Persistent poorly controlled inflammation may alter smooth muscle and matrix, contributing to less reversible airflow limitation over time.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Variable symptom pattern

Document wheeze, breathlessness, tightness and cough across nights, exercise, seasons, infections and allergen exposure.

Objective wheeze

Confirm polyphonic expiratory wheeze where possible and distinguish stridor, rattles and caregiver-described noisy breathing.

Current control

Ask daytime frequency, night waking, activity limitation, school absence and reliever use during the previous 4 weeks.

Future attack risk

Record previous emergency care, oral steroids, intensive care, SABA dispensing, low lung function and ICS gaps.

Atopy and comorbidity

Assess eczema, rhinitis, food allergy, sleep, obesity, reflux symptoms, anxiety and laryngeal or breathing-pattern symptoms.

Technique and context

Observe inhaler and spacer use and ask about access, routines, smoke, vaping, school arrangements and family priorities.

Red flags requiring action

Silent chest, cyanosis, altered consciousness, exhaustion, hypotension or poor respiratory effort indicates life-threatening asthma.
Stridor, drooling, sudden choking, unilateral signs or no response to bronchodilator suggests upper-airway obstruction or foreign body rather than asthma.
Persistent wet cough, clubbing, faltering growth, recurrent focal pneumonia or neonatal symptoms suggests cystic fibrosis, bronchiectasis or structural disease.
Previous intensive-care ventilation, recent severe attack, excessive reliever use and poor inhaled-corticosteroid adherence predict future fatal or near-fatal attacks.
Symptoms only with feeds, recurrent aspiration, cardiac signs or fixed monophonic wheeze requires an alternative pathway.
Adolescent smoking or vaping, psychosocial distress, medicine access and deliberate underuse must be assessed confidentially and without blame.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
First-line age 5–16: fractional exhaled nitric oxideFirst stepFirst line
Why
Identify type-2 airway inflammation within a suggestive history.
Interpretation and limitations
FeNO at least 35 ppb confirms asthma in the NICE algorithm; a lower value, especially after ICS, does not alone exclude it.
02
Spirometry with bronchodilator reversibility
Why
Demonstrate variable expiratory airflow limitation when FeNO is not raised or unavailable.
Interpretation and limitations
FEV1 increase at least 12% from baseline or 10% of predicted normal FEV1 supports diagnosis when testing quality is adequate.
03
Twice-daily peak flow for 2 weeks
Why
Provide an alternative objective variability measure when spirometry is unavailable or delayed.
Interpretation and limitations
Amplitude percentage mean variability at least 20% supports asthma; technique and adherence determine validity.
04
Allergy and eosinophil pathway
Why
Refine diagnosis when FeNO, reversibility and peak flow have not confirmed a still-suspected asthma phenotype.
Interpretation and limitations
NICE combines sensitisation or raised total IgE with eosinophils above 0.5 × 10^9/L; follow the complete algorithm.
05
Reference specialist bronchial challenge
Why
Demonstrate airway hyperresponsiveness when diagnosis remains uncertain after standard testing.
Interpretation and limitations
A positive validated challenge supports asthma; testing occurs in an experienced service with safety screening.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Viral-induced preschool wheeze

Wheeze confined to colds without interval symptoms may remit, although severe or atopic phenotypes need ongoing review.

Foreign body or focal obstruction

Sudden onset, unilateral wheeze or fixed monophonic noise warrants bronchoscopy assessment rather than escalating asthma treatment.

Bronchiectasis or cystic fibrosis

Persistent wet cough, clubbing, poor growth and recurrent bacterial infection indicate chronic suppurative lung disease. when timing, examination and trajectory are integrated.

Inducible laryngeal obstruction

Inspiratory throat tightness and rapid exercise-onset noise with normal expiratory testing may reflect laryngeal closure. when timing, examination and trajectory are integrated.

Cardiac, aspiration or dysfunctional breathing

Feeding association, murmur, syncope, sighing and symptoms discordant with objective airflow require targeted alternative assessment. when timing, examination and trajectory are integrated.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01DiagnoseBuild objective confirmationFirst stepA child aged at least 5 years has a suggestive variable symptom history.

1Treat urgent symptoms first and obtain FeNO before ICS where feasible.
2If unconfirmed, proceed through spirometry reversibility, peak-flow variability and allergy/eosinophil steps.
3Refer for specialist opinion and challenge when doubt remains rather than applying an unsupported label.

02Age 5–11Start anti-inflammatory maintenanceAsthma is newly diagnosed in a child aged 5–11 years.

1Offer twice-daily paediatric low-dose ICS with SABA as needed and teach the device and spacer.
2Review symptoms, attacks, adherence and technique and address smoke, rhinitis and access.
3If uncontrolled, use the MART or conventional age-specific NICE pathway and refer at moderate-dose failure.

03Under 5Use a time-limited treatment trialA preschool child has interval symptoms or severe recurrent wheeze warranting maintenance treatment.

1Give twice-daily paediatric low-dose ICS with SABA as needed for 8–12 weeks.
2AlternativeCheck technique, adherence, environmental factors and alternative diagnoses, then stop or continue according to response and recurrence.
3Trial LTRA only when appropriate and refer for poor response, admission or recurrent emergency care.

04ReviewCheck foundations before stepping upSymptoms, reliever use or attacks remain above the agreed target.

1Reconfirm diagnosis and observe every inhaler and spacer.
2Review dispensing, daily use, trigger exposure, comorbidities and the written plan.
3EscalationEscalate one evidence-based step, define the outcome and step down once stable control is sustained.

Key medicines and prescribing safety2 treatments · regimens, roles and cautions

First-line maintenance anti-inflammatory treatment that reduces symptoms and future attacks.

Paediatric low-dose inhaled corticosteroid

Use a licensed age-appropriate ICS and the current BTS, NICE and SIGN paediatric dose table, generally twice daily for children 5–11; under 5 use an 8–12 week twice-daily low-dose trial when indicated.

Dose equivalence varies by molecule and device. Teach spacer use and mouth rinsing, monitor height and total steroid burden, and use the lowest effective dose after stable control.

Alternative add-on when a child cannot manage MART or within the under-5 stepwise pathway.

Montelukast

Age 6 months–5 years: 4 mg orally at night; age 6–14 years: 5 mg at night; age 15 years and over: 10 mg at night. For asthma step-up, use an 8–12 week monitored trial and stop if ineffective.

Discuss MHRA neuropsychiatric warnings, including sleep, mood, behaviour and suicidal symptoms. Reassess benefit explicitly and do not continue an ineffective trial.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Severe asthma attack

Acute bronchoconstriction, mucus and oedema can cause hypoxaemia, fatigue, respiratory arrest and death. when recognition or effective treatment is delayed.

Activity and sleep impairment

Night waking, school absence and exercise avoidance affect learning, fitness, confidence and family life. when recognition or effective treatment is delayed.

Fixed airflow limitation

Repeated inflammation and remodelling can reduce maximal lung growth and later respiratory reserve. when recognition or effective treatment is delayed.

Treatment adverse effects

Poor technique increases oral candidiasis and dysphonia, while high steroid exposure can affect growth and adrenal function.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Review at least annually and after attacks, treatment changes, repeated reliever requests or school concerns.
Measure symptoms, night waking, activity, SABA use and attacks separately; good daily control does not erase attack risk.
Observe inhaler and spacer technique rather than asking whether it is good.
Check prescriptions collected and discuss barriers to regular anti-inflammatory treatment.
Monitor height and steroid burden, including oral courses and potent topical or intranasal products.
Update the personalised action plan and confirm school has immediate reliever access.
When stepping down, change one treatment at a time and arrange follow-up to detect loss of control.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Normal examination does not exclude asthma

Variability means chest signs and spirometry can normalise between episodes; repeat objective assessment when symptomatic if needed.

FeNO is treatment sensitive

Starting inhaled corticosteroid before testing may suppress the signal, so collect objective evidence early when clinical safety allows.

Reliever use is a risk marker

Frequent SABA requests reveal poor control or access and should prompt review rather than automatic repeat prescribing.

MART requires understanding

A licensed device alone is insufficient; the child and caregivers must know which inhaler provides both maintenance and relief.

Growth monitoring needs context

Use serial height and the lowest effective steroid dose while recognising that uncontrolled asthma also impairs growth and health.

11Common pitfallsFrequent interpretation and management errors.

01
Do not diagnose asthma from cough alone or caregiver use of the word wheeze.
02
Do not delay emergency treatment to obtain diagnostic tests.
03
Do not prescribe SABA without an age-appropriate anti-inflammatory strategy for confirmed asthma.
04
Do not step up before checking technique, adherence, access and diagnosis.
05
Do not use adult inhaler pathways for a child aged 5–11.
06
Do not prescribe unlicensed MART devices without explicit specialist and governance consideration.
07
Do not continue montelukast when ineffective or ignore neuropsychiatric symptoms.
08
Do not omit written action planning and post-attack review.