Asthma in children ≤ 5 years of age

Asthma is a respiratory disease that is characterized by chronic airway inflammation and commonly develops in childhood. In children ≤ 5 years of age, risk factors for asthma and asthma triggers are similar to older children and adults, but the diagnosis is based on clinical evaluation and does not include diagnostic studies (e.g., pulmonary function testing). A clinical diagnosis is made in children ≤ 5 years with all of the following: recurrent episodes of acute wheezing, alternative causes have been reasonably excluded, and there is a documented positive clinical response to pharmacological asthma treatment. Management of acute exacerbations is based on exacerbation severity and includes inhaled short-acting beta agonists (SABAs) with or without inhaled ipratropium bromide and systemic corticosteroids. Maintenance management follows a stepwise approach aimed at improving symptoms and quality of life while minimizing exacerbations and adverse effects of treatment. Pharmacological treatment typically includes as-needed SABAs for acute symptoms and inhaled corticosteroids (ICS) for more frequent symptoms. Long-term management should include regular follow-ups, a written asthma action plan, monitoring of response to pharmacological treatment, and adjustments as indicated.

• Prevalence in children 0–4 years of age: ∼ 2% ^[1]
• Children < 18 years of age: ♂ > ♀ ^[1]

Epidemiological data on children < 5 years of age with asthma are limited because the condition has been poorly defined in this age group. ^[2]

Epidemiological data refers to the US, unless otherwise specified.

Risk factors for developing asthma ^[3][4][5]

• Personal and/or family history of atopy, e.g.:
  • Atopic dermatitis
  • Allergic rhinitis and nasal polyps
  • Asthma
• Preterm birth and/or low birth weight
• Environmental exposures, e.g.:
  • Mold
  • Air pollution, including second-hand smoke exposure
  • Respiratory infections (e.g., bronchiolitis) in early childhood

Risk factors for asthma exacerbations in children ≤ 5 years ^[3]

• ≥ 1 acute wheezing episode in the preceding 12 months that required any of the following:
  • An emergency department visit
  • Hospitalization
  • A course of oral corticosteroids
• Uncontrolled asthma symptoms
• Inconsistent or incorrect use of ICS and/or medication device
• Exposure to asthma triggers
• Approaching seasons when asthma flare-ups occur
• Outdoor pollution
• Psychosocial or socioeconomic difficulties

Clinical features of asthma ^[3]

• Intermittent acute respiratory symptoms
  • End-expiratory wheezes with prolonged expiration
  • Dyspnea
  • Heavy or rapid breathing
• Nighttime or activity-associated dry cough or wheeze
• Features of common comorbid conditions (e.g., allergic rhinitis, atopic dermatitis)
• Lower level of physical activity compared to children of the same age

Clinical features of asthma exacerbations ^[3][6][7]

• Exposure to a known asthma trigger (e.g., URTI, exercise)
• Progressive increase in or development of asthma-related respiratory symptoms, e.g.:
  • Cough and/or wheezing
  • Decreased air entry
  • Dyspnea
  • Increased work of breathing (e.g., tachypnea, retractions, accessory muscle use)
  • Hypoxia, possibly with cyanosis
• Tachycardia
• Decreased oral intake
• Mental status changes: agitation, confusion, drowsiness
• For additional clinical features, see "Management of acute asthma exacerbations in children ≤ 5 years."

Clinical diagnosis of asthma in children ≤ 5 years ^[3]

Diagnose asthma if all 3 of the following criteria are met, and suspect asthma if 1–2 criteria are met. ^[3]

• Recurrent acute wheezing episodes
  • ≥ 2 acute wheezing episodes in the last 12 months ^[3]
  • OR ≥ 1 acute wheezing episode in combination with interval asthma symptoms ^[3]
• Exclusion of alternative causes of symptoms
• Symptom improvement with a pharmacological trial
  • SABA trial: acute symptom resolution following administration of an inhaled SABA ^[3]
  • ICS trial: reduction in interval and/or acute symptoms after 2–3 months of scheduled ICS ^[3]

Diagnose asthma in children ≤ 5 years if they have recurrent acute wheezing episodes, respond to asthma medications, and there is no alternative cause of the symptoms. ^[3]

Imaging, laboratory testing, and procedures are not typically required. ^[3][6]

Diagnostics ^[3][6]

Diagnostic testing is not routinely recommended. The following tests are not used to diagnose asthma, but they may exclude alternative diagnoses or guide management.

• Chest X-ray ^[8][9]
  • Indications: See "CXR in children with wheezing."
  • May identify alternative diagnoses or acute complications in patients with severe and/or atypical symptoms
  • Findings in acute exacerbation: nonspecific pulmonary hyperinflation and/or peribronchial cuffing ^[10]
• Allergy testing: skin prick test or allergen-specific IgE for suspected allergic triggers that will change management ^[6]

Pulmonary function testing and fractional exhaled nitric oxide are not used to diagnose asthma in children < 5 years. ^[3][6]

Do not routinely order chest x-ray for the diagnosis of asthma or for acute asthma exacerbations. ^[8][9]

Other causes of pediatric wheezing ^[3]

• Virus-induced wheezing
  • Recurrent wheezing with viral infections in children < 6 years of age
  • Management
    • Tailored to the patient and episode severity
    • Therapies include bronchodilators and inhaled corticosteroids.
• Vascular ring
• See also "Causes of wheezing in all ages" and "Causes of wheezing in children."

Other causes of cough in children ^[3][11]

The following conditions may also cause a subacute or chronic cough in children:

• URTI
• Allergic rhinitis
• Gastroesophageal reflux in children
• Infections (e.g., pertussis, persistent bacterial bronchitis, tuberculosis)
• Congenital immunodeficiency disorders
• Primary ciliary dyskinesia

The differential diagnoses listed here are not exhaustive.

General principles of asthma management ^[3][6]

• Initate prompt management of acute asthma exacerbations in children ≤ 5 years.
• Use appropriate devices to administer inhaled medications.
  • Preferred: an MDI with a spacer and either a facemask or a mouthpiece
    • < 4 years: spacer with facemask ^[3]
    • 4–5 years: spacer with mouthpiece ^[3]
  • Alternative: nebulizers (if caregivers cannot properly use a spacer)
• Educate patients and caregivers on the following:
  • Proper use of inhalers and devices
  • The chronic nature of asthma and the need for ongoing maintenance management
• Provide a written asthma action plan (see “Tips and links” for examples) to optimize adherence.
• Assess for indications for specialist referral.

Indications for specialist referral ^[3][6][7]

In addition to diagnostic uncertainty, refer patients with any of the following:

• Features suggestive of other causes of wheezing, e.g.: ^[3][6]
  • Symptoms not preceded by common asthma triggers
  • Failure to thrive
  • Onset of symptoms in the neonatal period
  • Respiratory symptoms accompanied by vomiting
  • Persistent wheeze or frequent stridor
  • Poor response to pharmacological treatment for asthma
  • Focal signs of pulmonary or cardiac disease (e.g., digital clubbing)
  • Baseline hypoxia (i.e., SpO₂ < 95%) ^[3]
• Features of or risk factors for severe or poorly controlled asthma ^[6][7]
  • Need for one or both of the following higher maintenance steps to control symptoms:
    • Step 4 management based on GINA severity ^[3]
    • Step 3 management based on NAEPP severity ^[6][7]
  • Nonpreferred or advanced treatments are being considered.
  • Risk factors for life-threatening asthma
  • Need for additional asthma education
• Treatment-related adverse effects (e.g., adverse effects of glucocorticoid therapy)

The following content is for children ≤ 5 years of age. For older individuals, see "Severity of asthma exacerbations in individuals > 5 years" and "Management of acute asthma exacerbations in individuals > 5 years."

Approach ^[3][6][7]

• Initiate prompt management (e.g., advanced airway management, pharmacological treatment) based on exacerbation severity.
• To guide disposition and treatment decisions, consider using severity assessment tools that have been validated for children, e.g.:
  • Pediatric Respiratory Assessment Measure (PRAM)
  • Pediatric Asthma Severity Score (PASS)
• If the response to initial management is insufficient, escalate management to the next severity level.
• Determine disposition (e.g., hospitalization, ICU) based on severity and response to treatment.

Management of exacerbations by severity ^[3][6][7]

Regardless of severity, consider closer observation and/or hospital admission for individuals with risk factors for life-threatening asthma. ^[3]

Emergency department or outpatient discharge criteria ^[3][6][7]

• Mild or moderate exacerbation with:
  • Sustained symptom resolution for 1–2 hours ^[3]
  • Caregiver who is able to observe the patient and complete treatment at home
  • No barriers to follow-up with primary care provider within 1–3 days ^[3]
• Caregivers have received education on:
  • Medication technique
  • Early signs of an asthma exacerbation
  • Asthma action plan

The goals of maintenance management include improving symptoms and quality of life while minimizing exacerbations and treatment-related adverse effects. Guideline recommendations from GINA and NAEPP are presented below. ^{[3] [6][7]}

Approach ^[3][6][7]

• Determine the initial asthma disease severity classification.
• Initiate stepwise asthma treatment based on severity. ^[3][6][7]
• Provide ongoing maintenance management with follow-up visits at least every 3–6 months.
• Ensure the asthma action plan is updated and a written copy is provided to the caregiver.

Oral bronchodilators are not recommended for asthma treatment because they take longer to achieve symptom control and have more adverse effects than inhaled medications. ^[3]

Nebulizers are an alternative for children if caregivers are unable to demonstrate proper use of a spacer. ^[3]

Initial maintenance management of asthma in children ≤ 5 years ^[3][6][7]

For children who are 5 years or older, see "Classification of asthma severity in individuals > 5 years of age," "Pharmacological treatment for asthma in individuals 6–11 years," and "Pharmacological treatment for asthma in individuals ≥ 12 years."

GINA asthma severity and management ^[3]

NAEPP initial asthma severity and management ^[6][7]

Initial severity is based on symptoms in individuals who are not receiving asthma maintenance therapy.

Ongoing maintenance management ^[3][6]

Maintenance follow-up visits

• Routine follow-ups every 3–6 months to address the following: ^[3]
  • Pediatric growth parameters (particularly linear growth) at least yearly
  • Control of asthma symptoms
  • Risk factors for asthma exacerbations in children ≤ 5 years
  • Medication use: adherence, administration technique
  • Review of adjunctive therapy for asthma (e.g., avoidance of triggers, recommended immunizations)
  • Adverse effects of treatment (e.g., adverse effects of glucocorticoid therapy)
• Following dose adjustments (i.e., step-up or step-down): Reassess within 3–6 weeks. ^[3][6]

Both ICS and poorly controlled asthma can affect growth; monitor children's height at least annually. ^[3]

Management based on asthma control ^[3][6][7]

• Assessment of asthma control is based on:
  • Daytime and nighttime symptoms occurring in the preceding 2–4 weeks ^{[3] [7]}
  • Frequency of asthma exacerbations in the preceding year
• Consider using severity assessment tools validated in young children. ^[3][12][13]

A quick evaluation for inadequate asthma control is the "Rule of Twos®": rescue inhaler use > 2 times/week, nighttime waking from asthma symptoms > 2 times/month, and the need for rescue inhaler refills > 2 times/year. ^[14]