Bronchial Asthma Guidelines
Core Definition and Pathophysiology
Asthma is a chronic inflammatory disorder of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, bronchial hyperresponsiveness, and underlying inflammation involving mast cells, eosinophils, T lymphocytes, and epithelial cells 1. The inflammation causes recurrent episodes of coughing (particularly at night or early morning), wheezing, breathlessness, and chest tightness with widespread but variable airflow obstruction that is often reversible either spontaneously or with treatment 1.
Diagnostic Approach
Confirming the Diagnosis
All patients should undergo spirometry or peak expiratory flow testing to confirm variable airflow limitation 2. The diagnostic pathway includes:
- Bronchodilation test: FEV1 improvement ≥12% and ≥200 ml absolute change from baseline (excluding respiratory infections within past 4 weeks) 3
- Bronchial provocation test: Should be considered when FEV1 is ≥70% predicted (excluding respiratory infections within past 4 weeks) 3
- Peak expiratory flow variability: ≥20% increase from baseline when spirometry unavailable 3
Presumptive Diagnostic Pathway
When clinical symptoms suggest asthma but standard tests are unavailable or inconclusive, do not rely solely on cutoff values to exclude asthma 3. Initiate diagnostic anti-inflammatory therapy if any of these criteria are met:
- Positive PEF-based bronchodilation test (≥20% increase)
- FEV1 variability ≥12% and ≥200 ml between two prior tests
- Small airway dysfunction (2 of 3 parameters ≤65% predicted: MEF25, MEF50, MMEF) or FEV1 improvement ≥10% with FeNO ≥35 ppb when baseline FEV1 ≥80% predicted 3
Biomarkers for Assessment
- Induced sputum eosinophil: Gold standard for airway inflammation assessment, phenotype classification, and corticosteroid response prediction 3
- Peripheral blood eosinophil ≥150/μl: Identifies eosinophilic phenotype or type 2 inflammatory endotype and predicts biologic response 3
- FeNO testing: Useful for identifying type 2 inflammation and monitoring treatment response 3, 4
Classification Systems
Severity Classification
Classify asthma severity based on the treatment steps required to achieve control, not on pre-treatment status 3. Once optimal control is achieved:
| Severity | Treatment Step Required |
|---|---|
| Intermittent | Step 1 |
| Mild Persistent | Step 2 |
| Moderate Persistent | Step 3 or 4 |
| Severe Persistent | Step 5 or 6 |
Assessment Domains
Evaluate asthma using two key domains that may respond differentially to treatment 1:
Impairment domain - Current or recent:
- Frequency and intensity of symptoms
- SABA use for quick relief (goal: ≤2 days/week)
- Functional limitations
- Pulmonary function status
- Patient/family satisfaction with care
Risk domain - Future likelihood of:
- Asthma exacerbations requiring ED visits or hospitalizations
- Progressive decline in lung function (or reduced lung growth in children)
- Medication adverse effects
Type 2 vs Non-Type 2 Inflammation
Type 2 airway inflammation is characterized by elevated blood/sputum eosinophils, and/or elevated FeNO, and/or atopy or elevated total IgE 3. This predominates in severe asthma and predicts response to biologic therapies.
Non-type 2 inflammation should only be identified after excluding confounders such as infections and medications 3.
Stepwise Pharmacologic Management
Universal Principle: No SABA Monotherapy
All adults, adolescents, and most children with asthma must receive ICS-containing therapy to reduce the risk of severe exacerbations and should never be treated with SABA alone 5, 2.
Treatment Tracks
The 2024 GINA strategy divides treatment into two tracks 5:
Track 1 (Preferred): As-needed low-dose ICS-formoterol as reliever Track 2: SABA as reliever with separate ICS inhaler
Step-by-Step Treatment Algorithm
Step 1 (Intermittent asthma):
- As-needed low-dose ICS-formoterol is the recommended treatment for patients with occasional transient daytime symptoms (<2 times/month, lasting hours), no nocturnal symptoms, no exacerbation risk, and FEV1 >80% predicted 3
Step 2 (Mild persistent):
- As-needed low-dose ICS-formoterol significantly reduces moderate-to-severe exacerbations compared with SABA monotherapy 3
- Alternative: Intermittent ICS administered at the same time as SABA to reduce symptom burden and minimize total ICS dose 4
Step 3 (Moderate persistent):
- ICS-LABA combination is equally preferred with increasing ICS dose alone for patients ≥5 years 1
- ICS-LABA demonstrates synergistic anti-inflammatory and anti-asthmatic effects, achieving efficacy equivalent to or better than doubling ICS dose, and improves adherence while reducing high-dose ICS-related adverse effects 3
Step 4 (Moderate-severe persistent):
- Preferred regimen is maintenance-and-reliever therapy (MART) with ICS-formoterol 2
- Triple combination inhalers (ICS-LABA-LAMA) can be prescribed to improve symptoms, lung function, and reduce exacerbations when asthma remains uncontrolled on medium- or high-dose ICS-LABA 3
- Patients with persistent symptoms despite correct inhalation technique and adherence should be referred to asthma specialists 3
Step 5-6 (Severe persistent):
- Continue high-dose ICS-LABA
- Add biologic therapy for severe type 2 asthma (see below)
- Low-dose OCS (≤7.5 mg/day prednisone equivalent) may be added as the last choice 3
ICS Safety Considerations
Long-term treatment with ICS at recommended clinical doses is safe 3. However, prolonged high-dose ICS therapy may lead to:
- Osteoporosis
- Suppression of hypothalamic-pituitary-adrenal axis
- Increased risk of pneumonia 3
Severe Asthma Management
Definition
Severe asthma is uncontrolled asthma despite 3 or more months of continuous standardized use of medium- or high-dose ICS-LABA, after treating comorbidities and avoiding environmental stimuli, or worsening after stepping down to lower dose ICS-LABA 3.
Biologic Therapies
Patients with severe type 2 asthma can be treated with biologic therapy 3:
- Anti-IgE monoclonal antibodies (omalizumab)
- Anti-IL-5 monoclonal antibodies (mepolizumab, reslizumab)
- Anti-IL-5Rα monoclonal antibodies (benralizumab)
- Anti-IL-4Rα monoclonal antibodies (dupilumab)
Those with good response to type 2-targeted biologic therapies can prioritize decreasing or stopping maintenance OCS therapy, but should not completely stop maintenance therapy with ICS-LABA 3.
Additional Severe Asthma Treatments
Add-on low-dose azithromycin therapy (250-500 mg/day, three times weekly for 26-48 weeks) may be prescribed for adult patients with persistent symptomatic asthma despite step 5 treatment to reduce exacerbations 3.
Bronchial thermoplasty is indicated for adult patients whose asthma remains uncontrolled despite optimized treatment and specialist referral, or for whom targeted biological therapy is not available or appropriate 3.
Immunotherapy
Subcutaneous immunotherapy in adults may reduce required ICS dosage and improve asthma-specific quality of life and lung function 3.
For house dust mite-sensitized adolescents or adults with FEV1 >70% predicted, HDM sublingual immunotherapy may be added to reduce symptoms and ICS dose if symptoms persist despite low-to-medium-dose ICS-containing therapy 3.
Managing Exacerbations
Home Management
Develop written asthma action plans instructing patients to 1:
- Recognize early signs, symptoms, and PEF measures indicating worsening
- Adjust medications (increase SABA and, in some cases, add oral systemic corticosteroids)
- Remove or withdraw from environmental factors contributing to exacerbation
- Monitor response and seek medical care if serious deterioration or lack of response
In early stages of mild-to-moderate exacerbations, when budesonide-formoterol is used as anti-inflammatory reliever, take 1-2 additional inhalations (160/4.5 μg strength), but daily dose should not exceed 8 inhalations 3.
Emergency Department Management
Assess initial severity by lung function measures and symptom/functional assessment 1:
- Supplemental oxygen
- Repetitive or continuous SABA
- Oral systemic corticosteroids
Consider adjunctive treatments (magnesium sulfate or heliox) in severe exacerbations (FEV1 or PEF <40% predicted) unresponsive to initial treatment 1.
At discharge, provide 1:
- Oral systemic corticosteroids
- Consider initiating ICS
- SABA medications
- Referral for follow-up care
- ED asthma discharge plan
- Review of inhaler technique and environmental control measures
Risk Factors for Asthma-Related Death
Critical risk factors requiring heightened vigilance 3:
- History requiring intubation and mechanical ventilation
- Hospitalization or emergency care visit for asthma in past year
- Currently using or recently ceased OCS
- No current ICS use
- Overuse of SABA (>1 canister salbutamol/month)
- Psychiatric illness or psychosocial problems, including sedative use
- Poor adherence
- Confirmed food allergy history
- Comorbidities including pneumonia, diabetes, and arrhythmias
Monitoring and Follow-Up
Initial Management Phase
Schedule follow-up visits every 2-4 weeks after initial therapy, then every 1-3 months if there is response 3. Regular training in correct inhaler technique is essential for optimal asthma control 3.
Ongoing Assessment
Assess severity to initiate therapy; assess control to adjust therapy 1. Once therapy is initiated, emphasis shifts to assessing asthma control to guide decisions to maintain or adjust therapy (step up if necessary, step down if possible) 1.
Instruct patients to monitor asthma control in an ongoing manner 1. Either symptom or peak flow monitoring is appropriate for most patients; evidence suggests benefits are similar 1.
Provocative Testing for Monitoring
Provocative dose causing 20% decrease in FEV1 in bronchial provocation test may reflect airway hyperresponsiveness and may be used in disease monitoring and therapeutic evaluation 3.
Psychosocial Assessment
Patients should undergo psychosocial assessment (anxiety/depression scales) and evaluation for comorbidities if they suffer from dyspnea/chest tightness after routine therapy with normalized lung function, peripheral blood eosinophil, and FeNO simultaneously 3.
Special Situations
Exercise-Induced Bronchospasm
Treatment strategies to prevent EIB 1:
- Long-term control therapy
- Pretreatment before exercise with SABA, LTRAs, cromolyn or nedocromil
- Warm-up period or mask/scarf over mouth for cold-induced EIB
- Frequent or chronic use of LABA for pretreatment is discouraged because it may disguise poorly controlled persistent asthma 1
Pregnancy
Monitor asthma control during all prenatal visits 1. Asthma worsens in 1/3 of women during pregnancy and improves in 1/3; medications should be adjusted accordingly.
It is safer to be treated with asthma medications than to have poorly controlled asthma 1. Maintaining lung function is important to ensure oxygen supply to the fetus.
- Albuterol is the preferred SABA 1
- ICS is the preferred long-term control medication (budesonide is preferred because more data are available during pregnancy) 1
Surgery
Assess asthma control before surgery 1. If lung function is not well controlled, provide medications to improve lung function; a short course of oral systemic corticosteroids may be necessary.
For patients receiving oral systemic corticosteroids during the month before surgery, and for selected patients on high-dose ICS, give 100 mg hydrocortisone intravenously during the surgical period; reduce the dose rapidly within 24 hours after surgery 1.
Atypical Asthma Phenotypes
Cough Variant Asthma
Treatment principles are the same as typical asthma, and most patients respond to ICS or ICS-LABA 3. ICS-LABA is recommended as first choice and should be used for more than 8 weeks 3.
For CVA patients with poor therapeutic response and severe airway inflammation, consider adding leukotriene receptor antagonist therapy or short-term use of OCS (10-20 mg/day, 3-5 days) 3.
Asthma Associated with Fungal Sensitization
Antifungal drugs can reduce airway inflammation and reduce systemic corticosteroid dose by minimizing fungal colonization and burden 3.
Anti-IgE, anti-IL-5, anti-IL-5Rα, anti-IL-4Rα monoclonal antibodies can reduce exacerbations, improve asthma control and lung function, and improve quality of life 3.
Aspirin-Induced Asthma
The most effective prevention is to avoid reapplication of aspirin 3. Desensitization therapy may be considered in AIA patients who require high-dose ICS to control symptoms, or who have failed to improve nasal inflammation and polyposis with conventional treatment, or who require aspirin for other diseases 3.
Asthma-COPD Overlap
Consider ACO diagnosis in patients with asthma who have 3:
- Persistent airflow limitation (FEV1/FVC <70% after bronchodilator)
- History of exposure to noxious gases or substances (smoking ≥10 pack-years)
- Emphysema on high-resolution CT
- Decreased diffusion capacity after 3-6 months of standardized treatment
Clinical Remission
After biologic therapy or other anti-asthma therapy, patients who achieve ≥1 year of symptom-free status, no exacerbation, normal/near-normal lung function, and no need for OCS may be considered to have achieved "clinical remission" 3.
Key Implementation Points
Treatment should be individualized through assessment, adjustment, and review 2. Asthma treatment is not "one size fits all" 2.
When developing control goals with patients, consider the health care system, availability of medications, cultural differences, and personal preferences 3.
All patients should have a written asthma action plan 5, and management should be tailored to help reduce serious exacerbations, fatalities, and hospitalizations 5.