Wheezing in children

What is wheezing?

Wheezing is a high-pitched, whistling sound that occurs when smaller airways are narrowed by presence of any of the following:

• Bronchospasm.

• Swelling of the mucosal lining.

• Excessive amounts of secretions.

• An inhaled foreign body.

Epidemiology

• Wheezing in children is common throughout childhood. Half of children will have at least one episode of wheeze before their first birthday and a third will have recurrent episodes of wheeze up until the age of five.¹

• One study of preschool children found that the presence of both exercise-induced wheeze and a history of atopic disorders indicated a likelihood of 53.2% developing asthma.²

Causes of wheezing (aetiology)¹

The commonest causes of wheeze in children presenting to general practice are viral-induced wheeze and wheeze associated with atopy.

• Viral respiratory tract infections:

  • Bronchiolitis.

• Bacterial respiratory tract infections:

  • Protracted bacterial bronchitis.

• Atopy:

  • Asthma.

  • Hay fever.

• Immunological deficiencies:

  • Cystic fibrosis.

  • Primary ciliary dyskinesia.

  • Immunological defects.

• Recurrent aspiration:

  • GORD.

  • Disorders of swallowing.

• Perinatal disorders:

  • Bronchopulmonary dysplasia.

  • Chronic lung disease.

• Anatomical:

  • Tracheoesophageal fistula or malacia.

  • Airway compression.

• Other causes:

  • Foreign body aspiration.

  • Metabolic disease.

See also the separate Lower respiratory tract infection in children and Children with respiratory difficulties articles.

Presentation and management

Always consider the presence of any red flags indicating the need for urgent assessment and treatment - eg, poor feeding, cyanosis, respiratory distress, drowsiness or poor response to treatment. See also the separate Children with respiratory difficulties article.

There are two main forms of presentation depending upon onset and age:

• Acute onset of wheezing in an infant.

• Recurrent or persistent wheeze.

Wheezing starting perinatally suggests structural abnormalities. Clubbing occurs in chronic lung infection, congenital heart disease and (rarely) in uncomplicated asthma.

Allergic rhinitis, urticaria and eczema may suggest asthma or an allergic reaction. Nasal polyps are often found in allergic conditions.

Investigation of possible causes

Many children who are otherwise well but who have recurrent wheeze do not need further investigations. The majority will have viral associated wheeze which resolves in between episodes.

Some children do need further investigations which may include:

• CXR: can demonstrate the presence of pneumonia, foreign body, structural anomalies, an enlarged heart, masses and pulmonary infiltrates.

• Allergy testing. This may be advised where there are clear symptoms of an allergy to a specific substance. Generalised allergy testing should not be offered to a wheezy child without evidence of an allergy.

Referral for further investigations may be needed for rarer causes. If there is any suspicion of a significant underlying condition including cardiac causes, previously undiagnosed cystic fibrosis or an anatomical abnormality then an urgent paediatric referral is required

Management of wheezing in children¹³

No treatment has been shown to prevent progression of preschool wheeze to school-age asthma. Treatment of wheeze is therefore only directed towards current symptoms. In all but the most severe cases, episodic symptoms should be treated with episodic treatment. If prophylactic treatment is initiated, it should be discontinued at the end of a strictly defined time period because many respiratory symptoms remit spontaneously in preschool children.

There is no justification for the routine use of antibiotics in a wheezy child as most have a viral cause. The use of antibiotics in infancy may increase the risk of asthma. Where there is evidence of protracted bacterial bronchitis, antibiotics may be of benefit. Recent studies have suggested that 90% of these children have prolonged wheezing.

Wheeze in an otherwise well child does not necessarily need to be treated but where treatment is required, the following treatments may be used:

Bronchodilators:

Short-acting beta-2 agonists are the commonest treatment for acute episodes of wheeze, cough and shortness of breath. They have been shown to be the most effective treatments in children under the age of two. A metred-dose inhaler is the preferred mode of delivery. This should be used with a spacer. Children with significant wheeze should be admitted.

Inhaler steroids:

Inhaled steroids can be effective in children with recurrent wheeze.⁴

Systemic steroids:

A short course of oral steroids has been shown to be beneficial in wheezy children, particularly where the wheeze is associated with a viral upper respiratory tract infection. Recent studies have confirmed the benefits of oral steroids in wheezing pre-school children with reductions in early wheezing severity and reductions in length of hospital stay.⁵

Leukotriene modifiers:

Montelukast has been shown to be of benefit, particularly in a post-viral wheeze. However a meta-analysis showed no clear evidence of benefit; it found no reduction in the use of corticosteroids and found that both oral and inhaled corticosteroids were significantly more efficacious than montelukast.⁶ The potential neuropsychiatric side effects of montelukast need to be considered before prescribing but it remains part of the British Thoracic Society Guidelines and NICE guidelines for management of a wheezy child.⁷

Prognosis

The prognosis of wheezing in children depends on the underlying cause.