Residency · Residency · Medicine-Pediatrics

Asthma Across the Lifespan

Overview

Asthma is the most common chronic disease of childhood and remains highly prevalent in adults. Pediatric asthma phenotypes (viral-induced wheeze, atopic asthma) differ from adult-onset asthma and asthma-COPD overlap. The Med-Peds physician must navigate different classification systems, stepwise therapy guidelines, and the expanding role of biologics while managing the unique challenges of adolescent asthma adherence.

Epidemiology

Pediatric prevalence: approximately 8% of US children; higher in Black and Puerto Rican children. Adult prevalence: approximately 8% of US adults. Childhood asthma is more common in boys; adult asthma is more common in women. Asthma is the leading cause of school absenteeism from chronic disease. Significant health disparities: Black children have 2x the prevalence, 4x the ED visit rate, and 8x the mortality rate compared to White children.

Asthma Phenotypes Across Ages

Pediatric Phenotypes

Viral-induced wheeze (transient early wheeze): most common in preschool children; triggered by viral URI (RSV, rhinovirus); often resolves by age 6; does not necessarily lead to persistent asthma. Atopic asthma: begins in early childhood; associated with eczema, food allergy, allergic rhinitis (atopic march); elevated IgE, eosinophilia, positive skin prick testing; likely to persist into adulthood. Exercise-induced bronchospasm: common in school-age children and adolescents; may be the only manifestation. Severe asthma: approximately 5% of pediatric asthma; often T2-high with eosinophilic inflammation; candidates for biologics.

Adult Phenotypes

Allergic (T2-high) asthma: continuation of childhood atopic asthma; eosinophilic, elevated FeNO, responds to ICS and biologics. Non-allergic (T2-low) asthma: adult-onset, often female, non-atopic, neutrophilic or paucigranulocytic; less responsive to ICS. Adult-onset eosinophilic asthma: late onset (>40), severe, often with nasal polyps and aspirin sensitivity (AERD/Samter triad) Obesity-related asthma: non-T2, mechanistic link through adipokines, airway compression, and systemic inflammation. Asthma-COPD overlap (ACO): features of both asthma and COPD; typically in patients >40 with smoking history and persistent airflow limitation plus reversibility; managed with ICS-containing regimens (never LAMA alone)

Diagnosis

Pediatric Diagnosis

In children <5: diagnosis is clinical; based on pattern of symptoms, response to bronchodilators, and exclusion of alternatives. Modified Asthma Predictive Index (mAPI): helps predict persistence of asthma in preschool wheezers. Positive mAPI: >=3 wheezing episodes/year PLUS 1 major criterion (parental asthma, eczema, aeroallergen sensitization) OR 2 minor criteria (food allergy, >=4% eosinophilia, wheeze without URI) In children >=5: spirometry with reversibility testing (>=12% and >=200 mL increase in FEV1 post-bronchodilator) Challenge testing: methacholine or exercise challenge if baseline spirometry is normal but clinical suspicion is high.

Adult Diagnosis

Spirometry: FEV1/FVC <0.70 with >=12% and >=200 mL reversibility post-bronchodilator. FeNO: >=25 ppb supports T2/eosinophilic inflammation (>=50 ppb highly suggestive) Methacholine challenge: PC20 <4 mg/mL diagnostic; useful when spirometry is normal. Peak flow variability: >20% diurnal variation supports diagnosis. Blood eosinophils: >=300 cells/mcL suggests T2-high phenotype; predicts biologic responsiveness.

Classification of Severity

NAEPP/EPR-3 Classification (Pediatric and Adult)

Intermittent: symptoms <=2 days/week, nighttime awakenings <=2x/month, SABA use <=2 days/week, no interference with activity, FEV1 >80%. Mild persistent: symptoms >2 days/week (not daily), nighttime 3-4x/month, minor limitation, FEV1 >=80%. Moderate persistent: daily symptoms, nighttime >1x/week, some limitation, FEV1 60-80%. Severe persistent: symptoms throughout the day, nighttime nightly, extreme limitation, FEV1 <60%.

Assessing Control (Ongoing)

ACT (Asthma Control Test): validated for ages >=12; score >=20 = well controlled. c-ACT (Childhood ACT): for ages 4-11. GINA assessment: symptom control (well controlled, partly controlled, uncontrolled) + risk factors for exacerbation.

Stepwise Therapy

GINA 2023 Updates (Adults and Adolescents >=12)

Track 1 (Preferred): ICS-formoterol as both maintenance and reliever (MART strategy) Step 1: as-needed low-dose ICS-formoterol. Step 2: low-dose ICS-formoterol maintenance + as-needed. Step 3: medium-dose ICS-formoterol maintenance + as-needed. Step 4: add-on LAMA (tiotropium); refer for phenotyping. Step 5: add-on biologic (based on phenotype); refer to specialist. Track 2 (Alternative): ICS-LABA with SABA reliever. Key change: GINA no longer recommends SABA-only treatment at any step; all patients should receive ICS (even if as-needed)

Pediatric Stepwise (NAEPP/EPR-4 2020 Focused Updates + GINA)

Ages 0-4: Step 1: as-needed SABA; Step 2: low-dose ICS daily; Step 3: medium-dose ICS; Step 4: medium-dose ICS + LABA or montelukast; referral; Ages 5-11: Step 1: as-needed SABA (GINA prefers as-needed ICS-SABA); Step 2: low-dose ICS daily; Step 3: low-dose ICS-LABA OR medium-dose ICS; Step 4: medium-dose ICS-LABA; Step 5: high-dose ICS-LABA; consider biologic, oral steroids; Ages >=12: follow adult GINA guidelines.

Key Medications

ICS: budesonide, fluticasone propionate, mometasone, beclomethasone. Growth suppression: small effect (~0.5-1 cm reduction in final adult height with low-dose ICS); benefits outweigh risks. LABA: formoterol (fast-onset, used in MART), salmeterol; NEVER use LABA alone without ICS (FDA black box, SMART trial) LTRA: montelukast; FDA black box warning for neuropsychiatric events (2020); use only if benefits outweigh risks. LAMA: tiotropium; add-on at Step 4-5; approved for ages >=6. SABA: albuterol (salbutamol); rescue therapy; overuse (>2 canisters/year) indicates poor control. Systemic corticosteroids: prednisone/prednisolone burst for exacerbations (1-2 mg/kg/day in children, 40-60 mg/day in adults, 3-5 days)

Biologic Therapies

Indications

Severe persistent asthma uncontrolled on Step 4-5 therapy. Phenotype-guided selection based on biomarkers (eosinophils, IgE, FeNO)

Available Biologics

Impact of Biologics

50-70% reduction in exacerbations; Oral corticosteroid sparing; Improved lung function and quality of life; Whether early biologic use in children alters disease natural history remains an open question.

Acute Asthma Exacerbation Management

Pediatric ED Management

Albuterol nebulization: 2.5-5 mg q20min x 3 doses, then q1-4h; or continuous nebulization (10-20 mg/hr) for severe. Ipratropium bromide: 0.25-0.5 mg nebulized q20min x 3 doses (first hour only, for moderate-severe) Systemic corticosteroids: dexamethasone 0.6 mg/kg (max 16 mg) x 1-2 doses increasingly preferred over 5-day prednisone burst (equivalent efficacy, better adherence) Magnesium sulfate: 25-75 mg/kg IV (max 2 g) for severe exacerbation not responding to initial therapy. IV terbutaline: for impending respiratory failure. Heliox: 70:30 or 80:20 helium-oxygen mixture to reduce airway resistance (limited evidence)

Adult ED Management

Albuterol MDI (4-8 puffs q20min) or nebulization (2.5-5 mg q20min) Ipratropium 0.5 mg nebulized q20min x 3 doses. Systemic corticosteroids: prednisone 40-60 mg PO or methylprednisolone 125 mg IV. Magnesium sulfate: 2 g IV over 20 minutes for severe exacerbation. BiPAP for impending respiratory failure. Intubation: ketamine as induction agent (bronchodilator properties); low respiratory rate, prolonged expiratory time on ventilator settings.

Asthma in Adolescents: Unique Challenges

Adherence is lowest in the adolescent age group. Common barriers: denial of disease, peer pressure, forgetfulness, steroid fears. Transition from parent-managed to self-managed care. Vaping and marijuana use exacerbate asthma. Exercise-related symptoms may limit sports participation (but exercise should be encouraged with proper pretreatment) Confidential assessment of adherence, substance use, and psychosocial factors.

<image>A stepwise therapy diagram comparing GINA 2023 adult/adolescent recommendations (Track 1 with ICS-formoterol MART approach at each step) with the pediatric stepwise approach for ages 0-4 and 5-11. Each step shows the preferred controller and reliever medications, with connecting arrows indicating step-up and step-down decisions based on symptom control and exacerbation risk. Biologic therapy options are displayed at Steps 4-5 with biomarker-based selection criteria shown in a decision box.</image>

<image>A phenotype classification wheel for asthma across the lifespan. The wheel is divided into segments representing different phenotypes: viral-induced wheeze (preschool, shown resolving by age 6), atopic/T2-high asthma (childhood through adulthood, largest segment), adult-onset eosinophilic asthma (late onset with nasal polyps), obesity-related asthma (T2-low), and asthma-COPD overlap (older adults). Each segment shows characteristic biomarkers (IgE, eosinophils, FeNO, neutrophils), typical patient demographics, and preferred treatment approach including specific biologic targets.</image>

<image>An acute asthma exacerbation management flowchart comparing pediatric and adult protocols side by side. Both start with severity assessment (mild/moderate/severe/life-threatening), then show parallel treatment pathways with age-appropriate dosing for albuterol, ipratropium, systemic steroids (highlighting dexamethasone single-dose option in pediatrics), and magnesium sulfate. Disposition decision points show PEF/FEV1 thresholds for discharge versus admission. Red flags for intubation are listed at the bottom with age-specific ventilator considerations.</image>

Clinical Pearls

GINA no longer recommends SABA-only treatment at any step -- even mild intermittent asthma should include ICS (at least as-needed ICS-formoterol) The SMART trial showed LABA monotherapy increased asthma deaths -- NEVER prescribe a LABA without an ICS. Montelukast carries an FDA black box warning for neuropsychiatric events (mood changes, suicidality) -- discuss risks and benefits, especially in children. Dexamethasone 0.6 mg/kg x 1-2 doses is increasingly replacing 5-day prednisone bursts for pediatric asthma exacerbations with equivalent efficacy and better adherence. Low-dose ICS causes approximately 0.5-1 cm reduction in final adult height -- this is clinically insignificant compared to the benefits of asthma control. Albuterol overuse (>2 canisters/year) is a marker of uncontrolled asthma and increased exacerbation risk -- not a solution. In adolescents, always ask about vaping and marijuana use as triggers for asthma exacerbation. Biologic selection should be guided by phenotype and biomarkers -- there is no one-size-fits-all approach.

References

• Global Initiative for Asthma (GINA). Global Strategy for Asthma Management and Prevention. 2023 Update.
• Expert Panel Working Group. 2020 Focused Updates to the Asthma Management Guidelines. J Allergy Clin Immunol. 2020;146(6):1217-1270.
• Castro M, Corren J, Pavord ID, et al. Dupilumab efficacy and safety in moderate-to-severe uncontrolled asthma. N Engl J Med. 2018;378(26):2486-2496.
• Chipps BE, Lanier B, Milgrom H, et al. Omalizumab in children with uncontrolled allergic asthma. J Allergy Clin Immunol. 2017;139(5):1431-1439.
• Kelly HW, Sternberg AL, Lescher R, et al. Effect of inhaled glucocorticoids in childhood on adult height. N Engl J Med. 2012;367(10):904-912.
• Keeney GE, Gray MP, Morrison AK, et al. Dexamethasone for acute asthma exacerbations in children: a meta-analysis. Pediatrics. 2014;133(3):493-499.

How to think about this

Asthma is a heterogeneous disease that evolves across the lifespan. As medicine-pediatrics physicians, you will encounter patients with asthma from infancy through geriatrics, each with unique diagnostic considerations, phenotypic presentations, and therapeutic approaches. The key is to recognize that what works for a 5-year-old with viral-induced wheeze may be very different from what is needed for a 50-year-old with adult-onset eosinophilic asthma. Focus on understanding the core principles of diagnosis (clinical history, spirometry with reversibility), classification (severity and control), and stepwise management, while appreciating the nuances that age and phenotype bring. Always remember the importance of patient education, adherence, and addressing health disparities in asthma care.

Check yourself with 2 bullets.

• Why is it inappropriate to prescribe a short-acting beta-agonist (SABA) alone for asthma, even for mild intermittent symptoms?
• What are two common phenotypic differences in asthma presentation between preschool children and adults over 40?

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