Asthma in adults: objective diagnosis, monitoring and long-term management

Clinical scope and diagnostic principle

Asthma is characterised by variable respiratory symptoms and variable expiratory airflow limitation or airway inflammation, but symptoms alone are not sufficiently specific to establish the diagnosis. The 2024 joint BTS, NICE and SIGN guideline strengthened the emphasis on objective confirmation. A suggestive history should lead to appropriate testing, with the record coded as suspected asthma until evidence supports confirmation. This reduces both under-treatment of genuine asthma and long-term inhaler treatment for alternative diagnoses.

Clinical history should explore episodic wheeze, cough, breathlessness and chest tightness, variability over time, night or early-morning symptoms, triggers, atopy and family history. Ask about smoking and vaping, occupational exposure and features pointing to other diagnoses. Physical examination may be normal between episodes, so a normal chest examination does not exclude asthma. If the person is acutely unwell, treat the acute clinical problem first and complete objective testing when it is safe and interpretable.

Objective testing in adults

For adults with a history suggestive of asthma, the joint guideline recommends an objective sequence beginning with blood eosinophils or fractional exhaled nitric oxide where available. A raised eosinophil count above the laboratory reference range or FeNO at or above the guideline threshold can support the diagnosis. If these do not confirm asthma, bronchodilator reversibility with spirometry is used. A meaningful rise in FEV1 after bronchodilator supports variable airflow obstruction.

If spirometry is unavailable or delayed, structured peak-expiratory-flow monitoring twice daily for two weeks can demonstrate significant variability. When the diagnosis remains uncertain despite these assessments, bronchial challenge testing may be considered through specialist services. Test interpretation should account for prior inhaled corticosteroid exposure because anti-inflammatory treatment can make FeNO and spirometry appear more normal. The diagnostic record should state which objective evidence supported the final diagnosis.

Assessing control and modifiable causes of poor control

Control should be assessed at each review. Useful domains include current symptoms, night waking, activity limitation, reliever use, time off work, oral corticosteroid courses, emergency attendance and hospital admission. Validated symptom questionnaires such as the Asthma Control Test can provide a reproducible measure but should sit alongside clinical assessment. Routine peak-flow diaries are not required for every stable adult unless there is a person-specific reason or they form part of an action plan.

Before escalating medication, actively look for reasons why apparently severe asthma is not controlled. Confirm the diagnosis, inspect inhaler technique, assess adherence, review smoking or vaping, occupational and environmental exposures, seasonal factors, comorbidity and psychosocial influences. Poor technique and inconsistent use can mimic pharmacological treatment failure. Where available, FeNO and eosinophils may help identify persistent type 2 inflammation or poor adherence and can inform specialist referral.

Inhaled corticosteroid-containing treatment

A major principle of the current guideline is that short-acting beta2 agonist treatment should not be prescribed as stand-alone asthma therapy. Adults and young people with asthma should have inhaled corticosteroid-containing treatment because this addresses airway inflammation and reduces exacerbation risk. The preferred pathway for many people aged 12 and over uses an ICS/formoterol combination as anti-inflammatory reliever therapy, with maintenance-and-reliever therapy introduced when control requires regular maintenance treatment.

MART simplifies treatment by using an ICS/formoterol inhaler for both maintenance and symptom relief at the relevant treatment steps. Device choice, licensed regimen, dose and maximum daily use must be checked against the current guideline and product information. If asthma remains uncontrolled on an appropriate MART regimen despite good adherence and technique, reassess inflammatory markers where available and consider specialist referral or add-on treatment according to the pathway. Escalation should be reviewed after an appropriate interval rather than continued without evidence of benefit.

Self-management, action plans and risk reduction

Every person with asthma benefits from understanding how to recognise deterioration and what action to take. A personalised written asthma action plan should connect symptoms, reliever use and any agreed peak-flow thresholds with clear treatment and escalation instructions. Education should cover inhaler technique, adherence, trigger management and how to obtain urgent help. The plan needs review when treatment changes, after an exacerbation and when the patient’s circumstances alter.

Risk is not captured by daily symptom burden alone. A person with infrequent symptoms can still experience a serious exacerbation. Previous hospitalisation, repeated oral corticosteroid courses, excessive reliever use, poor adherence to anti-inflammatory therapy, smoking, psychosocial complexity and comorbidity are important warning features. Prescription records can reveal reliever overuse or poor preventer collection that is not apparent from a brief consultation. Higher-risk patients benefit from proactive follow-up rather than routine annual review alone.

Occupational asthma, pregnancy and referral

Adult-onset asthma or deterioration associated with work should trigger questions about whether symptoms improve away from the workplace, including weekends and holidays. Suspected occupational asthma should be referred promptly because delay can worsen long-term outcome and employment consequences can be substantial. Objective work-related monitoring may be required through specialist services.

Pregnancy should prompt continuation of effective asthma control rather than unnecessary withdrawal of treatment. Poorly controlled asthma itself carries maternal and fetal risk, so medicines are reviewed using the guideline and pregnancy-specific prescribing information. Refer for specialist assessment when the diagnosis remains uncertain, symptoms are uncontrolled despite appropriate therapy and adherence, severe exacerbations recur, inflammatory markers suggest potential biological treatment eligibility, or an alternative or complicating diagnosis is suspected.

Practice points and limitations

The central practice messages are to confirm asthma objectively where possible, avoid SABA-only prescribing, use ICS-containing therapy, check technique and adherence before escalating, and provide a written self-management plan. Documenting the objective basis of diagnosis is particularly valuable because it prevents future clinicians from treating an unverified label as established fact.

This resource addresses chronic adult asthma management and does not cover the detailed treatment of an acute severe asthma attack or specialist severe-asthma biologic pathways. Individual inhalers differ in licence, dose and device technique, so the current NG245 algorithms, product characteristics and local formulary should be consulted when prescribing.

Review quality, inhaler technique and treatment de-escalation

A high-quality asthma review is more than a symptom check. Ask the patient to demonstrate inhaler technique with the device they actually use, because technique errors differ between pressurised metered-dose inhalers, dry-powder devices and soft-mist devices. Check whether a spacer is indicated and whether the patient can generate the inspiratory flow needed for their device. Technique should be revisited after a device change, after an exacerbation and when control deteriorates without an obvious cause.

Prescription history can reveal clinically important patterns. Frequent reliever collection, repeated oral corticosteroid courses or long gaps in anti-inflammatory treatment suggest increased risk even when the patient describes current symptoms as mild. Explore practical barriers such as cost in non-NHS settings, work patterns, health literacy, concerns about corticosteroids and difficulty coordinating doses. A collaborative plan that addresses the reason for poor adherence is more likely to succeed than simply increasing the prescribed step.

When asthma has been stable for a sustained period, consider whether maintenance therapy can be reduced in line with the guideline. De-escalation should be planned, with a clear baseline assessment and follow-up rather than a sudden withdrawal of anti-inflammatory treatment. Review should also confirm vaccination status where relevant, smoking cessation support, occupational exposure and the continuing accuracy of the diagnosis. A patient whose symptoms no longer fit asthma may need reassessment rather than indefinite escalation or continuation of treatment based on an old label.

Comorbid conditions can materially influence both symptoms and control. Rhinitis, gastro-oesophageal reflux, obesity, dysfunctional breathing, inducible laryngeal obstruction, anxiety and cardiac disease may contribute to breathlessness or cough. Their presence does not exclude asthma, but treating the airway alone may leave the patient symptomatic. When objective asthma markers are reassuring yet symptoms remain prominent, reconsider the differential diagnosis and the contribution of comorbidity before escalating corticosteroid exposure. This protects patients from unnecessary treatment while keeping attention on the true cause of persistent limitation.