How do I manage wheezing that occurs during a viral respiratory infection in adults, children, and infants, with or without a history of asthma or chronic obstructive pulmonary disease?

Management of Wheezing During Viral Respiratory Infections

The management of viral-associated wheezing depends critically on distinguishing between two fundamentally different pathologies: viral bronchitis/bronchiolitis (neutrophil-dominated airway secretions) versus viral-triggered asthma exacerbation (bronchoconstriction), with the former requiring only supportive care while the latter benefits from bronchodilators and corticosteroids. 1

Step 1: Differentiate the Underlying Pathology

In Infants and Young Children (<2 years)

Viral bronchiolitis is the primary diagnosis when you observe:

• Preceding upper respiratory symptoms (runny nose) followed by lower airway signs 2
• Expiratory wheeze and/or crackles on auscultation 2
• Tachypnea and increased work of breathing 2
• Age <2 years with first or second episode 2

This is NOT asthma - it represents neutrophil-dominated inflammation with airway secretions ("snotty lung"), not bronchoconstriction. 1

In Children >1 Year and Adults

Consider viral-triggered asthma exacerbation when:

• Recurrent episodes of wheezing beyond the first year of life (these are NOT bronchiolitis) 2
• At least 2 of the following: wheezing, prolonged expiration, smoking history, or allergy symptoms 3, 4
• Previous diagnosis of asthma or positive asthma predictive index 3
• Viral infections trigger 50-85% of asthma exacerbations 3, 5

Key distinction: Bronchoconstriction responds to bronchodilators and steroids; airway secretions do not. 1

Step 2: Risk Stratification

High-Risk Features Requiring Close Monitoring or Hospitalization

In infants/children:

• Age <12 weeks 2
• Prematurity, especially <32 weeks gestation 2
• Hemodynamically significant cardiopulmonary disease 2
• Chronic lung disease of prematurity 2
• Immunodeficiency 2
• Moderate-to-severe respiratory distress 2
• Apnea 2
• Inability to feed or dehydration 2

In adults:

• Age >75 years with fever 6
• Cardiac failure, insulin-dependent diabetes, or serious neurological disorder 6

Step 3: Treatment Based on Pathology

For Viral Bronchiolitis (Infants/Young Children)

Supportive care ONLY - no medications are indicated: 2

• Nasal suctioning to clear secretions 2
• Positioning with head of bed elevated 2
• Adequate hydration 2
• Supplemental oxygen only if SpO2 <90% 2

Do NOT use:

• Bronchodilators (ineffective for secretion-based obstruction) 2
• Corticosteroids (no benefit) 2
• Antibiotics (viral illness) 2

Natural history: Self-limited, resolves in 8-15 days; 90% cough-free by day 21. 2

For Viral-Triggered Asthma Exacerbation

Standard asthma exacerbation management:

• Short-acting beta-agonists for bronchoconstriction 3
• Systemic corticosteroids to restore bronchodilator responsiveness 3, 1
• Consider initiating or stepping up inhaled corticosteroids for long-term control 3

For children with recurrent viral-triggered wheezing AND positive asthma predictive index (parental asthma, atopic dermatitis, or aeroallergen sensitization): 3

• Initiate daily inhaled corticosteroids 3
• Consider seasonal prophylaxis during high-risk periods (viral seasons) 3

Step 4: Rule Out Pneumonia

Obtain chest X-ray if any of the following are present: 4

• New focal chest signs on auscultation 4
• Dyspnea or tachypnea 4
• Pulse >100 bpm 4
• Fever persisting >4 days 4
• Dull percussion note or pleural rub 4

Use CRP to refine suspicion: CRP <20 mg/L makes pneumonia unlikely; CRP >100 mg/L makes it likely. 4

Step 5: Assess for Undiagnosed Chronic Airway Disease

Consider lung function testing in adults/older children with: 3

• At least 2 of: wheezing, prolonged expiration, smoking history, allergy symptoms 3, 4
• Up to 45% of patients with acute cough >2 weeks have undiagnosed asthma or COPD 3, 6

Common Pitfalls to Avoid

Do not treat viral bronchiolitis as asthma - the pathology is fundamentally different (secretions vs. bronchoconstriction), and asthma medications provide no benefit. 1

Do not assume all wheezing in young children is bronchiolitis - children with recurrent episodes after age 1 year likely have asthma and should be treated accordingly. 2

Do not continue "asthma medications" for persistent cough after bronchiolitis unless there is additional evidence of true asthma (positive predictive index, response to therapy). 2

Do not prescribe antibiotics reflexively - viral respiratory infections do not benefit from antibiotics and contribute to resistance. 6

Reassess if cough persists >3-4 weeks - this warrants evaluation for alternative diagnoses including pertussis, atypical bacteria, protracted bacterial bronchitis, or true asthma. 2, 6