• CPD Modules
• General Practice
• Respiratory

Diagnosis and management of asthma in adults and adolescents

By Dr Dermot Nolan - 17th Apr 2026

---

Reference:

---

Start this Module to earn CPD Points today

Click the "Start Module" button below

Asthma is one of the most common chronic diseases affecting people around the world at all life stages. Severe disease may cause a substantial burden on individuals and health services, including premature death or a severely reduced quality of life.

Global patterns are similar across children, adolescents and adults, but the burden, in terms of prevalence and severity of disease, is highest in adolescents. Asthma affected an estimated 262 million people in 2019 and caused 455,000 deaths.¹

Asthma cannot be cured, but it can be managed with appropriate use of medication, allowing patients to enjoy a normal and active life.

Updates for 2025/26

The Global Initiative for Asthma (GINA) 2025 and the 2024 British Thoracic Society (BTS), UK National Institute for Health and Care Excellence (NICE) and Scottish Intercollegiate Guidelines Network (SIGN) joint guideline have provided refined direction for the diagnosis and management of asthma in both adults and adolescents.^2,3

These updates emphasise early and continuous use of anti-inflammatory therapy, objective diagnostic testing, personalised treatment, and patient empowerment. The approach continues to evolve from one focused purely on symptom relief to one centred on long-term inflammation control and reduction of exacerbation risk.

The GINA 2025 framework reinforces that asthma is a heterogeneous disease and that each patient’s management plan should be adapted to their phenotype, comorbidities, and lifestyle.²

The most important principle remains that SABA-only treatment is no longer appropriate at any disease stage. Instead, inhaled corticosteroid (ICS)-formoterol therapy should serve as both reliever and controller to reduce the risk of severe exacerbations and hospitalisation.

The BTS/NICE/SIGN 2024 joint guideline covers diagnosing, monitoring and managing asthma in adults, young people, and children.³ This guidance document complements GINA by embedding objective diagnostic testing into every diagnostic pathway.

Clinicians are now expected to confirm the diagnosis using spirometry, bronchodilator reversibility (BDR), or fractional exhaled nitric oxide (FeNO), ensuring diagnostic precision. This is particularly important given evidence showing that up to 30 per cent of adults previously labelled with asthma do not meet the objective diagnostic criteria when retested.⁴

Equally, underdiagnosis remains problematic, delaying early anti-inflammatory treatment in symptomatic patients.

Disease mechanisms

Asthma is a chronic inflammatory disorder of the airways, marked by airway hyper-responsiveness, mucosal oedema, and variable airflow limitation. This inflammatory process leads to symptoms such as wheeze, cough, breathlessness, and chest tightness, which often vary over time and in intensity.

Symptoms typically worsen at night or in the early morning, and may be triggered by allergens, exercise, infections, or environmental irritants.^1,5

The underlying pathophysiology is characterised by immune-mediated inflammation. Type 2 (T2) inflammation remains the most prevalent and clinically significant pattern, driven by cytokines including IL4, IL5, and IL13. These cytokines lead to eosinophilic infiltration, increased FeNO, and elevated IgE levels.

Chronic inflammation contributes to structural airway changes or ‘remodelling’, including smooth muscle hypertrophy and subepithelial fibrosis, which in turn can cause irreversible airflow limitation in some individuals.⁵

COMMON ASTHMA PHENOTYPES

Allergic asthma: Early-onset, often associated with eczema, rhinitis, or food allergies; generally responsive to ICS therapy.

Non-allergic asthma: Lacks identifiable allergic sensitisation; often less responsive to ICS and may involve neutrophilic inflammation.

Adult-onset asthma: More common in females, often severe, non-allergic, and associated with comorbidities such as obesity.

Type 2 (eosinophilic) asthma: Driven by T2 inflammation with elevated FeNO and eosinophil counts; highly responsive to corticosteroids and biologic therapy. Various conditions including atopic dermatitis and rhinitis are linked to type 2 inflammation.

Non-type 2 asthma: Includes neutrophilic or paucigranulocytic subtypes, less steroid responsive, requiring alternative or adjunctive strategies such as macrolides or biologics targeting non-T2 pathways.

Recognition of asthma phenotypes supports more precise treatment, especially in refractory or severe cases. For example, high FeNO and eosinophils predict good corticosteroid response, whereas non-type 2 asthma may benefit from targeted non-steroidal interventions.^2,3

Severe asthma with type 2 inflammation is associated with a higher risk of exacerbation, hospitalisation, and death than when type 2 inflammation is not present.

Diagnosis

A careful and detailed history remains essential. Asthma symptoms are typically variable, episodic, and triggered by factors such as viral infection, allergen exposure, exercise, and air pollution. Common features include:

• Wheeze and dyspnoea worse at night or early morning.
• Cough that varies in intensity and frequency.
• Symptoms that improve spontaneously or with bronchodilator or ICS therapy.

The presence of comorbidities (allergic rhinitis, reflux, obesity, anxiety) or occupational exposures should be assessed. These factors can either mimic or exacerbate asthma, complicating diagnosis.

Accurate diagnosis depends on demonstrating variable expiratory airflow limitation or airway inflammation.³

• FeNO testing: FeNO measures airway nitric oxide, reflecting type 2 inflammation. FeNO ≥50ppb in adults or ≥35ppb in children supports asthma when consistent with symptoms. Intermediate levels (25-49ppb) should be interpreted contextually with spirometry and eosinophil counts. Persistently low FeNO (<25ppb) suggests non-eosinophilic disease.

FeNO testing bridges the diagnostic gap in primary care. It is quick, reproducible, and correlates with airway inflammation. High FeNO values guide clinicians to optimise ICS or MART therapy, while low readings encourage review of adherence or alternative diagnoses. FeNO can also support step-down decisions in stable patients.

When integrated with symptom scoring, spirometry, and eosinophil counts, FeNO enhances diagnostic confidence, guides biologic eligibility, and helps reduce unnecessary escalation of therapy.

• Spirometry and bronchodilator reversibility: Diagnosis is confirmed when FEV₁ increases by ≥12 per cent and ≥200mL following inhaled bronchodilator (200-400mcg salbutamol). Persistent obstruction despite therapy suggests fixed airflow limitation or an alternative diagnosis.
• Peak expiratory flow (PEF) variability: Diurnal variation >10 per cent over two weeks (adults) or >13 per cent (children) supports asthma. PEF diaries remain valuable where spirometry is unavailable.
• Blood eosinophils: Eosinophil counts >0.3 × 10⁹/L indicate type 2 inflammation and are predictive of good ICS response. Repeated testing is useful where results are borderline or variable.

Misdiagnosis contributes to unnecessary ICS use and missed alternative conditions. Conversely, under-recognition can delay intervention, increasing morbidity. Confirming diagnosis before initiating long-term ICS is therefore central to both guidelines.

Management principles

Asthma treatment should aim for complete symptom control, prevention of exacerbations, and maintenance of normal activity. Achieving this requires both pharmacological and non-pharmacological measures, continuous education, and shared decision-making.^2,3

The 2025 GINA update retained the Track 1 and Track 2 approach introduced in 2020-21, and builds on the changes made in 2019.

Track 1 (preferred):
Track 1 remains the preferred regimen for adults and adolescents. ICS-formoterol serves as both maintenance and reliever therapy (MART). This strategy simplifies treatment, improves adherence, and reduces exacerbation risk by ensuring anti-inflammatory therapy with every inhalation.⁶

Steps 1-2 (mild asthma): As-needed low-dose ICS-formoterol only.
Step 3: Low-dose maintenance ICS-formoterol + as-needed ICS-formoterol (MART).
Step 4: Medium-dose ICS-formoterol (MART) for daily symptoms or low lung function.
Step 5: Specialist referral for biologic therapy (anti-IgE, anti-IL-5, anti-IL-4Rα, anti-TSLP) or assessment of comorbidities.

Track 2 (alternative):
When Track 1 is unavailable or unsuitable, a daily ICS or ICS/LABA with SABA as reliever is acceptable, but SABA-only treatment is contraindicated. Patients using only a SABA are at increased risk of hospitalisation and mortality.

STEPWISE ADJUSTMENT:

Step-up: Evaluate adherence, inhaler technique, and environmental triggers before escalating treatment. Step-up if symptoms persist beyond two to three months despite good adherence.
Step-down: Once control is achieved for two to three months, reduce ICS dose gradually while maintaining monitoring.

Adjunct and add-on therapies

LTRA: Useful in patients with allergic rhinitis or aspirin-exacerbated respiratory disease.
SLIT: Consider for grass pollen-driven allergic asthma.

Biologics: Targeted for severe type 2 asthma. Choice depends on biomarker profile and phenotype:^2,3,7,8
Omalizumab: Anti-IgE for allergic asthma.
Mepolizumab/Reslizumab: Anti-IL-5 for eosinophilic asthma.
Benralizumab: Anti-IL-5R with enhanced eosinophil depletion.
Dupilumab: Anti-IL-4Rα for type 2 inflammation with atopy or dermatitis.
Tezepelumab: Anti-TSLP, effective across both type 2 and non-type 2 inflammation.⁸

Long-term management relies on structured reviews that incorporate objective monitoring, education, and partnership with the patient.

Key review elements include:

• Symptom tracking using validated tools, eg, Asthma Control Test (ACT) and Asthma Control Questionnaire (ACQ).
• Objective testing (spirometry, FeNO, or PEF trends).
• Adherence checks and review of inhaler technique at every visit.
• Trigger management – smoking cessation, allergen control, and avoidance of occupational irritants.
• Education and empowerment: personalised asthma action plans, shared decision-making, and accessible patient resources.

Addressing comorbidities such as rhinitis, sinusitis, gastro-oesophageal reflux, obesity, and anxiety significantly improves outcomes. Exercise and weight optimisation, psychological support, and allergen avoidance remain important components of holistic asthma care.⁷

Conclusion

Asthma is one of the most common chronic respiratory conditions, with burdensome implications in terms of morbidity and cost for the patient and healthcare system. The first step in reducing this burden is for clinicians to be able to recognise the classical respiratory symptom patterns of asthma, allied to objective documentation of variable expiratory airflow limitation to confirm the diagnosis.

Treatment of asthma has evolved over the last number of years. Chief among this being GINA’s recommendation that ICS-formoterol form the cornerstone of asthma management.

New biological and immunological therapies have now entered the management protocol across all severities of asthma, which will further reduce the symptom burden on patients.

Clinicians should strive to implement and encourage adherence to personalised asthma management plans.

Key takeaways:

• Confirm asthma using objective measures (spirometry, FeNO, eosinophils) and clinical correlation.
• Adopt ICS-formoterol as the cornerstone of treatment across all stages (GINA Track 1).
• Avoid SABA-only therapy at all stages.
• Tailor therapy according to phenotype, biomarkers, and comorbidities.
• Step therapy up or down based on control, adherence, and lung function.
• Engage patients in shared decision-making and maintain written action plans.
• Use FeNO and eosinophils to refine management and identify candidates for biologic therapy.

Start this Module to earn CPD Points today

Click the "Start Module" button below