CLINICAL ACTIONS:

Asthma is a common lung disorder characterized by chronic airway inflammation, which causes the bronchi to swell and narrow the airways (bronchospasm), causing reversible, recurrent airway obstruction. Patients can experience episodic exacerbations (or attacks) that can be severe and even life-threatening. History and physical are important, not only for making the diagnosis, but also to help guide classification which is essential for the management plan. Spirometry should be used in all patients >5 years of age to confirm the diagnosis. Type 2 asthma is characterized by eosinophic and/or allergic inflammation and is sometimes treated differently.

History: Key Elements

• Wheezing
• Cough
• Shortness of breath
• Difficulty breathing
• Chest tightness
• All symptoms but especially coughing are often associated with:
  • Timing: at night or on waking, sometimes with menstrual cycle
  • Exercise
  • Laughing/crying
  • Smoke
  • Allergens (mold, animal fur, pollen)
  • Extreme heat/cold
  • Viral infections
• Symptoms may interfere with normal activities
• Symptoms typically variable over time and in intensity
• More difficult to diagnose with patients already on inhaled corticosteroid (ICS) treatment

Physical Exam

• Auscultation: Listen for the following:
  • Expiratory wheezing (though in extreme causes this might be absent due to severely reduced airflow)
  • Note crackles and inspiratory wheezing are not features of asthma
  • Normal exam (often)
• Other clinical findings: Include assessment of the following
  • ENT: Ears, nose, throat for swelling, drainage due to allergy and/or inflammation
  • Chest: Hyper expansion of thorax (especially children)
  • Skin and eyes: Atopic dermatitis | Eczema | Evidence of allergic condition

Chronic Airways Assessment Test (CAAT)

The CAAT is a standardized patient-centered 8-item tool, which can be used to assess symptoms of both asthma and COPD.

Types of Asthma

• Type 2 asthma
  • Often begins in childhood | associated with history of allergic diseases or eczema | eosinophilic airway inflammation | responds well to ICS treatment
• Non-allergic asthma
  • Reduced short-term response to ICS
• Cough variant asthma and cough predominant asthma
  • Cough may the only reported symptom | possible now airflow limitation without provocation | ICS treatment is effective
• Adult-onset (late-onset) asthma
  • More common in women | usually non-allergic | requires higher doses of ICS
• Asthma with persistent airflow limitation
  • Thought to be due to airway wall remodeling
• Asthma with obesity
  • Little eosinophilic airway inflammation but prominent respiratory symptoms

Diagnostic Tests

Spirometry

• Test used for both diagnosis and monitoring
• Normal FEV1 score: ≥80 % of predicted value
• FEV₁ < 60% identifies patients at risk of asthma exacerbations, independent of symptom levels
  • Tests the forced expiratory volume of air that can be exhaled during forced breath
    • FEV₁ (forced expiratory volume): Volume exhaled in the first second
    • FVC (forced vital capacity): Total volume exhaled after a deep breath
    • FEV₁/FVC ratio: When FEV1 <80% of FVC, suspicious for obstructive rather than restrictive lung disease (more likely to decrease proportionally)
    • If FEV₁ increases ≥12% and ≥200 mL from baseline after bronchodilator indicative of reversible airway obstruction 
• FEV6 (volume after 6 seconds) can be considered rather than FVC in adults for whom full exhalation may take several seconds and be associated with light-headedness
• Contraindications to spirometry include: unstable cardiac disease or recent MI | aneurysms | recent thoracic or abdominal surgery | active viral infection | unexplained hypertension

Bronchial Provocation Tests

• Assess airway hyperresponsiveness with a challenge agent
  • Methacholine | histamine | exercise | eucapnic voluntary hyperventilation | inhaled mannitol
• Moderate sensitivity for diagnosis

Allergy Tests

• Particularly helpful for patients with atopy when allergic asthma is suspected
• Tests below can be helpful but only history can confirm is a specific trigger is related to asthma symptoms
  • Skin pricking test – Inexpensive and highly sensitive
  • Serum IgE measurement

Fractional Exhaled Nitric Oxide (FeNO)

• Measures the nitric oxide, a byproduct of inflammation, in exhaled breath
• Elevated FeNO supports diagnosis of asthma
• Low FeNO does NOT rule it out because not elevated in some asthma phenotypes (neutrophilic asthma | asthma with obesity)
• Can be elevated in non-asthma conditions as well (eosinophilic bronchitis | atopy | allergic rhinitis | atopic dermatitis)
• FeNO >50 ppb supports diagnosis of Type 2 asthma
• May be useful in diagnosing, managing and predicting future exacerbations in some types of asthma
• May be used as an adjunct to the evaluation process or when spirometry is unavailable

Blood eosinophil count

• Elevated level can support Type 2 asthma
• Low levels do not rule out asthma
• Blood eosinophils can be elevated in many non-asthma conditions
• May be falsely low if patient is using corticosteroids

Imaging

• Not routinely used to diagnose asthma but can assess for comorbid conditions or alternative diagnoses
• CT of the lungs can identify: bronchiectasis | emphysema | lung nodules | airway wall thickening | lung distention
• Important for assessment of other causes of respiratory disease, or other causes of exacerbation and/or worsening symptoms (e.g., pneumonia | foreign body in airways)

SYNOPSIS:

While targeted questions and examination are helpful, a good overall history and physical remain important to identify co-morbidities (e.g., sinusitis, rhinitis, GERD, other respiratory disorders, obstructive sleep apnea). It is also important to remain cognizant that multiple external factors can trigger an attack, including respiratory infections, smoking, allergies, exposure to cold or humid air, pollution, exercise, severe emotional and/or physical stress. Spirometry is currently the primary diagnostic tool for asthma.

KEY POINTS:

Severity of Asthma

• Asthma severity is determined by the following
  • Reported symptoms over the previous two to four weeks
  • Standardized questionnaires – e.g., the Asthma Control Test
    • Provides numerical score to determine if the symptoms are well controlled
• Current level of lung function: Peak expiratory flow rate (PEFR) | FEV₁ | FEV₁/FVC
• Number of exacerbations requiring oral glucocorticoids in the previous year

Types of Asthma

The historic categories of “intermittent,” “mild persistent,” moderate persistent,” and “severe persistent” are no longer being used. Instead, GINA recommends assessing asthma severity based on symptom control and risk of adverse outcomes.

Mild Asthma

• Defined as asthma that is well controlled with low-intensity treatment (as needed low dose ICS-formoterol OR low-dose ICS plus as-needed SABA)
• The historic distinction between mild intermittent and mild persistent are no longer considered useful. GINA recommends against prescribing SABA-only (e.g. albuterol) treatment.
• Prescribe a combined ICS-formoterol inhaler as-needed for patients with mild symptoms instead. Evidence shows reductions in exacerbations with this treatment.
• Avoid reliance on SABA as main asthma treatment

Moderate Asthma

• Defined as asthma that is well controlled with low- or medium-dose maintenance ICS-LABA

Severe Asthma

• Defined as asthma that requires high-dose maintenance ICS-LABA OR remains uncontrolled despite this treatment.

When to refer to pulmonologist and/or allergist/ immunologist 

• Difficulty confirming the diagnosis
• Suspected occupational asthma requiring confirmatory testing
• Persistent or severely uncontrolled asthma or frequent exacerbations
• History of near-fatal asthma exacerbation (ICU admission or mechanical ventilation) at any time in the past
• Evidence, or risk of, significant treatment side effects or need for long-tern corticosteroid use

Learn More – Primary Sources

GINA: Global Strategy for Asthma Management and Prevention (2026)

US DOH: Focused Updates to the Asthma Management Guidelines (2020)

ATS: Asthma Center