Chronic Lower Airway Disease
Asthma
A heterogeneous chronic respiratory disease characterized by variable symptoms and variable expiratory airflow limitation.
Clinical vignette
A child with recurrent cough and wheezing
An 8-year-old presents with cough, chest tightness, and wheezing after several days of rhinorrhea. He has nighttime cough twice weekly and develops similar symptoms with exercise. Examination reveals tachypnea, subcostal retractions, diffuse expiratory wheezing, and prolonged expiration.
Your first clinical task
Assess the severity of the current exacerbation while also recognizing the pattern of chronic asthma symptoms.
Anatomy localization
Asthma is a disease of the conducting airways
Asthma primarily affects the medium and small bronchi through inflammation, bronchial smooth muscle constriction, and mucus production resulting in variable airflow obstruction.
Structures involved
- • Medium and small bronchi
- • Bronchial smooth muscle
- • Airway mucosa
- • Goblet cells and mucus glands
Structures usually spared
- • Alveoli
- • Pleural space
- • Pulmonary vasculature
- • Lung parenchyma
Clinical implication
Because asthma affects the conducting airways rather than the alveoli, patients typically present with wheezing, prolonged expiration, chest tightness, and airflow obstruction rather than focal crackles or consolidation.
Pathophysiology
Inflammation plus reversible airway narrowing
Airway inflammation
Chronic inflammation makes the airways hyperresponsive to triggers.
Bronchoconstriction
Airway smooth muscle contracts, producing variable airflow obstruction.
Mucus production
Increased secretions further narrow the airway lumen.
Air trapping
Expiration becomes prolonged and incomplete, causing hyperinflation.
History and physical exam
Confirm the pattern and identify risk
History
- • Episodic wheeze, cough, dyspnea, or chest tightness
- • Nighttime or early-morning symptoms
- • Exercise, viral, allergen, smoke, or weather triggers
- • Prior emergency visits, hospitalization, or intubation
- • Controller adherence and inhaler technique
- • Atopy, eczema, allergic rhinitis, and family history
Physical exam
- • Respiratory rate and oxygen saturation
- • Retractions and accessory muscle use
- • Ability to speak, feed, or ambulate
- • Wheezing and prolonged expiration
- • Air entry, including a concerning silent chest
- • Mental status and signs of fatigue
Preschool wheeze
What does “reactive airway disease” actually mean?
Reactive airway disease (RAD) is a nonspecific clinical term, not a defined diagnosis. It is sometimes used when a young child has recurrent wheezing or apparent airway reactivity but the underlying diagnosis has not yet been established.
Viral-induced wheeze
Some preschool children wheeze primarily during viral respiratory illnesses and are well between episodes. Not every child with viral-associated wheezing will develop persistent asthma.
Increasingly suggestive of asthma
Recurrent episodes, symptoms between illnesses, multiple triggers, atopy, family history, and a reproducible response to asthma therapy increase confidence in the diagnosis.
Age alone does not determine the diagnosis. Preschool children can be diagnosed with asthma when the clinical pattern is convincing, even when they are too young to perform reliable spirometry.
Acute severity
How sick is the child right now?
Mild
Speaks normally, mild wheeze or retractions, good air movement.
Moderate
Increased work of breathing, more persistent wheeze, reduced activity or speech.
Severe
Marked retractions, difficulty speaking, poor air entry, agitation, or hypoxemia.
Impending respiratory failure
Fatigue, altered mental status, cyanosis, silent chest, or worsening despite treatment.
Interactive assessment
Assess acute asthma severity
Select the child's current findings to practice integrating the features that determine acute asthma severity.
Step 1 of 5
Work of breathing
Work of breathing
This educational tool does not replace your institution's pediatric asthma pathway or patient-specific clinical assessment.
Differential diagnosis
Not every wheezing child has asthma
Bronchiolitis
Usually a first episode in an infant with viral symptoms, crackles, and diffuse wheezing.
Foreign body aspiration
Abrupt onset, choking history, asymmetric air entry, or focal wheeze.
Pneumonia
Fever, focal crackles, focal decreased air entry, or toxic appearance.
Anaphylaxis
Acute respiratory symptoms with urticaria, angioedema, hypotension, or gastrointestinal symptoms.
Vocal cord dysfunction
Inspiratory symptoms, throat tightness, stridor, or poor response to asthma therapy.
Diagnostic workup
Confirm variable airflow obstruction and avoid unnecessary testing
Asthma is diagnosed by a characteristic pattern of variable respiratory symptoms together with objective evidence of variable expiratory airflow limitation when testing is feasible.
Initial evaluation
- • Detailed symptom and trigger history
- • Prior exacerbations and response to treatment
- • Physical examination and oxygen saturation
- • Assessment of atopy and relevant comorbidities
- • Review of inhaler technique and medication adherence
Objective lung-function testing
- • Perform spirometry with bronchodilator testing when the child is developmentally able
- • Look for reduced expiratory airflow before treatment
- • Repeat testing after an inhaled bronchodilator
- • Improvement in airflow supports variable, reversible obstruction
- • Normal spirometry between episodes does not completely exclude asthma
When the diagnosis remains uncertain
Additional options
- • Repeat spirometry during symptoms
- • Serial peak expiratory flow measurements
- • Exercise or bronchoprovocation testing
- • Specialist-directed allergy evaluation
Fractional exhaled nitric oxide
FeNO may support the diagnosis of type 2 airway inflammation when asthma remains uncertain, but it should be interpreted as an adjunct rather than used alone to diagnose or exclude asthma.
Avoid routinely in a typical exacerbation
- • Chest radiograph
- • CBC or inflammatory markers
- • Respiratory viral testing
- • Blood cultures
- • Arterial or venous blood gas
- • CT imaging
Consider targeted testing when
- • Findings are focal or markedly asymmetric
- • Foreign body aspiration is possible
- • Pneumonia or pneumothorax is suspected
- • The diagnosis is uncertain or the course is atypical
- • The child fails to improve as expected
- • Respiratory failure or another complication is suspected
Severe-asthma warning
A normal or rising carbon dioxide level may be ominous
Early in an asthma exacerbation, children commonly hyperventilate and lower their carbon dioxide level. In a child with severe distress, a normalizing or rising carbon dioxide level may indicate worsening fatigue and inadequate ventilation.
Decreasing wheeze with worsening air movement may represent a silent chest—not clinical improvement.
Management overview
Treat bronchoconstriction and inflammation
Short-acting bronchodilator
Administer inhaled albuterol for acute bronchoconstriction.
Systemic corticosteroid
Use early for moderate or severe exacerbations or incomplete response to initial bronchodilator therapy.
Oxygen
Provide supplemental oxygen when hypoxemia is present.
Escalation
Consider repeated or continuous bronchodilator therapy, ipratropium, magnesium, and higher-level respiratory support according to severity and local pathway.
Chronic-care principle
Asthma management should include an inhaled corticosteroid-containing strategy, assessment of symptom control and future risk, inhaler technique, adherence, trigger reduction, and a written asthma action plan.
Chronic management
Control today, reduce risk tomorrow
Long-term asthma management goes beyond treating acute wheezing. Assess current symptom control and future exacerbation risk, select an age-appropriate ICS-containing treatment strategy, address modifiable factors, and reassess the response over time.
Asthma control and asthma severity are different
Control
Describes how well symptoms are currently controlled and the patient's risk of future exacerbations or other adverse outcomes.
Severity
Is assessed retrospectively by the level of treatment required to achieve and maintain good asthma control.
Stepwise controller therapy
Match treatment to age, control, and risk
Asthma treatment differs by age. Select an age group to review the general stepwise approach, then reassess response and adjust treatment over time.
CHILDREN 6–11 YEARS
Stepwise ICS-containing treatment
STEP 1
Symptoms 2 days per week or less
Use an ICS-containing anti-inflammatory reliever strategy rather than relying on SABA alone.
STEP 2
Symptoms about 3–4 days per week
Daily low-dose inhaled corticosteroid therapy is a standard controller strategy, paired with an appropriate anti-inflammatory reliever plan.
STEP 3
Symptoms most days or nighttime waking
Options include low-dose ICS-LABA, medium-dose ICS, or low-dose maintenance-and-reliever therapy (MART) with ICS-formoterol.
STEP 4
Persistent symptoms or high-risk features
Escalate ICS-containing treatment according to the current age-specific pathway and consider specialist involvement when asthma remains poorly controlled despite optimized treatment.
STEP 5
Persistent uncontrolled asthma
Refer for expert assessment, confirm the diagnosis and modifiable factors, characterize the asthma phenotype, and consider advanced add-on treatment when appropriate.
Treatment choices vary by age, available inhaler formulations, local pathways, and patient-specific factors. Use current pediatric asthma guidance when selecting a specific medication and dose.
Asthma action plan
Every patient needs a plan for what happens next
A written asthma action plan helps patients and caregivers recognize worsening asthma, understand which medications to use, and know when to seek medical care. Review and update the plan as treatment and asthma control change.
Green zone
Doing well
No significant asthma symptoms, normal activity, and no nighttime awakening from asthma.
Follow the prescribed everyday controller and reliever strategy.
Yellow zone
Asthma is worsening
Increasing cough, wheeze, chest tightness, nighttime symptoms, or limitation of usual activity may signal worsening asthma.
Follow the patient-specific reliever and escalation instructions in the written action plan.
Red zone
Medical alert
Severe breathlessness, difficulty speaking or walking, cyanosis, markedly reduced air movement, or inadequate response to reliever therapy are concerning findings.
Follow the emergency instructions in the action plan and seek urgent medical care.
Before the patient leaves
Make sure the patient and caregiver understand the written plan, can demonstrate correct inhaler and spacer technique, know which medications are controllers and relievers, and understand when and where to seek additional care.
Severe asthma & biologic therapy
Advanced: phenotype-directed therapy for selected patients with severe asthma.
Severe asthma & biologic therapy
Advanced: phenotype-directed therapy for selected patients with severe asthma.
Severe asthma & biologic therapy
Treat the phenotype, not just the symptoms
Biologic therapy is reserved for selected patients with severe asthma that remains uncontrolled despite optimized standard therapy. Before labeling asthma as severe, confirm the diagnosis and address adherence, inhaler technique, medication access, environmental exposures, and comorbidities.
IgE
Allergic asthma
Omalizumab targets IgE and may be considered in eligible patients with severe allergic asthma.
IL-5 pathway
Eosinophilic asthma
Mepolizumab targets IL-5 and may be considered in eligible patients with severe eosinophilic asthma.
IL-4 / IL-13 pathway
Type 2 asthma
Dupilumab blocks IL-4 receptor alpha signaling and may be considered in eligible patients with severe eosinophilic or Type 2 asthma.
The clinical reasoning sequence
Uncontrolled asthma does not automatically mean severe asthma. First confirm the diagnosis and optimize conventional treatment. If asthma remains uncontrolled, specialist evaluation can identify the inflammatory phenotype and determine whether targeted add-on therapy is appropriate.
Biologic eligibility depends on age, asthma phenotype, biomarkers, exacerbation history, previous treatment, regulatory approval, and payer-specific criteria. Selection should be individualized with specialist involvement.
Disposition
Reassess the response—not just the initial appearance
Disposition depends on the child's clinical response after initial treatment, oxygen requirement, work of breathing, air movement, ability to speak or feed, prior high-risk history, and the safety of outpatient follow-up.
Consider discharge
- • Symptoms and work of breathing are substantially improved
- • Air movement is good without concerning fatigue
- • Oxygenation is stable on room air
- • Bronchodilator treatments can be spaced appropriately
- • The child can speak, drink, and ambulate near baseline
- • Caregivers understand treatment and return precautions
- • Reliable follow-up and access to medications are available
Consider hospital admission
- • Persistent moderate or severe respiratory distress
- • Continued oxygen requirement or recurrent hypoxemia
- • Need for frequent or continuous bronchodilator therapy
- • Incomplete or short-lived response to initial treatment
- • Poor oral intake, dehydration, or inability to manage at home
- • High-risk history or significant comorbidity
- • Unsafe social situation or unreliable follow-up
Escalate to intensive care
- • Worsening despite aggressive initial therapy
- • Markedly reduced air movement or silent chest
- • Exhaustion, confusion, drowsiness, or agitation
- • Persistent or worsening hypoxemia
- • Rising carbon dioxide or evidence of ventilatory failure
- • Need for advanced or rapidly escalating respiratory support
- • Concern for impending respiratory arrest
Discharge bundle
Stabilization is only half of the job
Confirm an inhaled corticosteroid-containing treatment plan
Provide an appropriate reliever plan
Complete the prescribed systemic corticosteroid course when indicated
Demonstrate inhaler and spacer technique
Review triggers, adherence, and barriers to obtaining medication
Provide a written asthma action plan
Give clear return precautions
Arrange timely outpatient follow-up
High-risk history
Prior intensive-care admission, previous intubation, recent emergency visits or systemic corticosteroid courses, poor controller adherence, medication-access barriers, and psychosocial concerns should lower the threshold for observation, admission, or specialist involvement.
Exact admission, oxygen, and bronchodilator-spacing criteria vary by institution. Apply the local pediatric asthma pathway when making clinical decisions.
Clinical pearls
High-yield asthma takeaways
Wheezing intensity does not equal disease severity
A silent chest is an emergency
Treat before ordering routine tests
Look beyond the current exacerbation
Inhaler technique is part of the treatment
Asthma control and asthma severity are not the same
Every child needs a plan after stabilization
Do not miss
Less wheezing can mean less airflow.
Always interpret wheezing together with air entry, respiratory effort, speech, oxygenation, fatigue, and mental status.
Knowledge check
Test your asthma reasoning
Question 1
A 9-year-old with known asthma presents with diffuse wheezing, moderate intercostal retractions, difficulty speaking in full sentences, and an oxygen saturation of 91%. What is the most appropriate initial treatment?
Anki Deck
Asthma
Reinforce the highest-yield concepts from this module with 16 spaced-repetition cards.
Requires Anki. Deck content is intended for educational review and should be used alongside the full PediAtlas module.
Evidence Base
Clinical References
Global Strategy for Asthma Management and Prevention, 2026.
2020 Focused Updates to the Asthma Management Guidelines.
Educational Disclaimer
PediAtlas is intended for medical education and should not replace institutional guidelines, local protocols, patient-specific assessment, or clinical judgment.