Overview

Definition

Asthma is a long-term inflammatory condition of the airways characterised by variable respiratory symptoms and variable airflow obstruction

Do not confirm asthma without a suggestive clinical history and supportive objective testing

Where testing is unavailable, record suspected asthma and do not delay treatment if the patient is symptomatic or acutely unwell

Causes and associated factors

Personal or family history of asthma or allergic rhinitis
Atopy including eczema and hay fever
Environmental allergens including pollen, dust mites and mould
Viral respiratory infections
Smoking, passive smoking or vaping
Occupational exposure to fumes, dust or chemicals
Air pollution

Pathophysiology

Airway inflammation: swelling of the airway lining with increased mucus production
Airway hyperresponsiveness: excessive narrowing in response to triggers
Variable airflow obstruction: bronchoconstriction that changes over time
Airway remodelling: persistent poorly controlled inflammation may lead to less reversible obstruction

Common triggers

Exercise
Cold air or weather changes
Respiratory infections
Smoke, vaping or air pollution
Pollen, pets, dust mites or mould
Emotional stress or laughter
NSAIDs or beta blockers in susceptible patients
Occupational exposure

Symptoms and examination

Typical symptoms	Features supporting asthma	Examination
Wheeze SOB Chest tightness Cough	Symptoms vary over time Worse at night or early morning Seasonal symptoms Triggered by exercise, infection or allergens	May be normal between episodes Wheeze when breathing out Prolonged breathing out Fast breathing during an attack Increased effort of breathing if severe

Consider another diagnosis if there is:

Haemoptysis
Persistent non-variable breathlessness
Stridor or monophonic wheeze
Clubbing or crackles
Unexplained fever or wt loss
Features of cardiac disease

Investigations

Arrange objective testing before ICS treatment where possible, as treatment may reduce FeNO, eosinophils and airflow variability

Do not delay treatment if the patient is symptomatic or acutely unwell

Test	Why it is needed	Supportive finding
FBC with eosinophils	Looks for eosinophilic airway inflammation	Eosinophils above 0.4
FeNO	Assesses eosinophilic airway inflammation	FeNO 50 or above
Spirometry with reversibility	Assesses airflow obstruction and reversibility	FEV₁ improvement of at least 200 mL and 12% from baseline, or at least 10% of predicted normal
PEF diary	Assesses variability when spirometry is normal or unavailable	Twice-daily readings for 2 weeks with amplitude percentage mean of at least 20%
Bronchial challenge	Specialist test where diagnostic uncertainty remains	Positive bronchial hyperresponsiveness

Normal spirometry does not exclude asthma

Reconsider the diagnosis if objective tests are repeatedly negative or the response to treatment is poor

Additional investigations

CXR: atypical symptoms or suspected alternative diagnosis
ECG: palpitations, chest pain or possible cardiac cause
Allergy testing: where identifying an allergen may alter management
Occupational assessment: ask whether symptoms improve away from work

Management pathway

All patients should receive an ICS-containing inhaler

Do not use SABA alone for ongoing asthma management

Preferred SABA-free pathway

Step	When to use	Treatment options	Review
Step 1 AIR	Newly diagnosed asthma or infrequent symptoms where AIR is suitable	Symbicort Turbohaler 200/6 Try 1 puff when required Alternative devices Vivaire 100/6, try 1 puff when required Fostair pMDI 100/6, try 1 puff when required using a spacer	Review symptoms, reliever use, adherence and inhaler technique
Step 2 Low-dose MART	Poor control on AIR or regular symptoms	Symbicort Turbohaler 200/6 Try 1 puff BD and 1 puff when required Fostair Nexthaler 100/6 Try 1 puff BD and 1 puff when required Fostair pMDI 100/6 Try 1 puff BD and 1 puff when required using a spacer	Review after 8-12 weeks
Step 2+ Moderate-dose MART	Persistent poor control despite good adherence and technique	Symbicort Turbohaler 200/6 Try 2 puffs BD and 1 puff when required Fostair Nexthaler 100/6 Try 2 puffs BD and 1 puff when required Fostair pMDI 100/6 Try 2 puffs BD and 1 puff when required using a spacer	Review after 8-12 weeks and check eosinophils or FeNO
Add-on	Persistent symptoms after checking diagnosis, adherence, technique and comorbidities	Montelukast Try 10 mg at night for 8 weeks Spiriva Respimat Try 2 puffs OD for 8 weeks	Stop add-on treatment if there is no clear benefit
Step 3 High dose treatment	Persistent uncontrolled asthma requiring specialist input	Fostair Nexthaler 200/6 Try 2 puffs BD Relvar Ellipta 184/22 Try 1 puff OD Consider ICS/LABA/LAMA treatment where appropriate	Urgent specialist review
Step 4 Triple therapy	Poor control despite high dose ICS/LABA	Fostair Nexthaler 200/6 Try 2 puffs BD plus Spiriva Respimat Try 2 puffs OD	Specialist asthma service

Before increasing treatment:

Check the diagnosis
Check adherence and inhaler ordering history
Check inhaler technique
Check that the device is suitable
Review smoking and vaping
Review rhinitis, obesity, reflux, anxiety and other comorbidities
Update the personal asthma action plan

Montelukast advice

May be useful where allergic rhinitis or atopy is present
Try 10 mg at night for 8 weeks
Stop if there is no clear improvement
Explain the risk of sleep disturbance, anxiety, mood changes, hallucinations or behavioural changes
Advise the patient to stop treatment and seek review if significant neuropsychiatric symptoms develop

General asthma care

Review at least annually
Review 8-12 weeks after treatment changes
Review within 48 hours of A&E attendance or hospital discharge
Check adherence and inhaler technique at every review
Provide and update a personal asthma action plan
Offer smoking and vaping cessation support
Offer annual flu vaccination
Use a spacer with a compatible pMDI
Advise rinsing the mouth after ICS use
Consider stepping down after at least 3 months of good control

Acute asthma

Severity	Clinical features	Action
Severe	PEF 33-50% of best or predicted Unable to complete sentences in one breath RR at least 25 PR at least 110	Same day hospital assessment
Life-threatening	PEF below 33% Oxygen sats below 92% Silent chest Cyanosis Poor breathing effort Exhaustion or confusion Bradycardia or hypotension	Call 999 immediately

Initial treatment

Give oxygen to maintain sats between 94-98% where available
Try salbutamol 4-10 puffs through a spacer, one puff at a time, repeated every 10-20 minutes according to response
For severe or life threatening asthma, use oxygen-driven nebulised salbutamol 5 mg where available
Add nebulised ipratropium 500 micrograms for severe or life-threatening asthma
Try prednisolone 40-50 mg OD for at least 5 days or until recovery
Do not leave the patient unattended

Referral

Urgency	Referral criteria
Same day assessment required	Severe or life-threatening acute asthma Incomplete response to initial treatment Rapid deterioration Repeated high-dose reliever use Suspected pneumothorax or another serious diagnosis
Urgent specialist review	Two or more attacks requiring oral corticosteroids in 12 months Hospital admission with asthma Uncontrolled asthma despite good adherence and correct technique High-dose ICS/LABA or triple therapy required Possible severe asthma or need for biologic treatment Asthma and COPD overlap
Routine referral	Diagnostic uncertainty Suspected occupational asthma Symptoms worse at work and better away from work Persistent symptoms with normal inflammatory markers Suspected dysfunctional breathing

If symptoms worsen, reliever treatment is not lasting, they are struggling to speak, becoming exhausted or developing blue lips, call 999