Asthma Management Handbook

Considering further investigations in children


Consider allergy tests for children with recurrent wheezing when the results might guide you in (either of):

  • assessing the prognosis (e.g. in preschool children, the presence of allergies increases the probability that the child will have asthma at primary school age)
  • managing symptoms (e.g. advising parents about management if avoidable allergic triggers are identified).

Note: Allergy tests are not mandatory in the diagnostic investigation of asthma in children.

How this recommendation was developed


Based on clinical experience and expert opinion (informed by evidence, where available).

If the diagnosis is uncertain, consider arranging bronchial provocation (challenge) testing or cardiopulmonary exercise testing to exclude asthma.

How this recommendation was developed


Based on clinical experience and expert opinion (informed by evidence, where available).

Arrange chest X-ray if the child has unusual respiratory symptoms or if wheezing is localised. Routine chest X-ray is not otherwise recommended in the investigation of asthma symptoms in children.

How this recommendation was developed


Based on clinical experience and expert opinion (informed by evidence, where available).

Measurement of exhaled nitric oxide is not recommended as a diagnostic test for asthma in routine clinical practice.

How this recommendation was developed


Based on clinical experience and expert opinion (informed by evidence, where available), with particular reference to the following source(s):

  • Brand et al. 2008 1
  • Dweik et al. 2011 2

Routine microbiological investigations are not recommended in the investigation of symptoms that suggest asthma in preschool children.

How this recommendation was developed


Based on clinical experience and expert opinion (informed by evidence, where available), with particular reference to the following source(s):

  • Brand et al. 2008 1

Offer referral to a specialist for further assessment and investigation if the diagnosis is unclear or if a serious condition cannot be ruled out. 

How this recommendation was developed


Based on clinical experience and expert opinion (informed by evidence, where available).

More information

Relationship of allergies to asthma

A history of other atopic conditions (e.g. eczema and rhinitis) increases the probability of asthma in wheezing children.3

A family history of asthma or allergies in a first-degree relative is a risk factor for atopy and asthma in children.34 Maternal atopy is most strongly associated with childhood onset of asthma and for recurrent wheezing that persists throughout childhood.3

Allergy tests in children

Skin-prick testing

Allergy tests have a very limited role in the clinical investigation of asthma. They may be useful to guide management if the child is sensitised to aeroallergens that are avoidable (e.g. advise parents  against getting a cat if skin-prick testing has shown that the child is sensitised to cat allergens, or advise parents that there is no need to remove a family pet if the child is not sensitised).

Skin-prick testing is the recommended test for allergies in children.

Risk factors for anaphylaxis during skin prick testing are thought to include asthma (particularly uncontrolled or unstable asthma), age less than 6 months, and widespread atopic dermatitis in children.5 As a precaution, the Australasian Society of Clinical Immunology and Allergy (ASCIA) advises that skin prick testing should be performed only in specialist practices for children under 2 years and children with severe or unstable asthma.5 ASCIA’s manual on skin prick testing lists other risk factors.5

Total serum IgE testing

In children aged 0–5 years, total serum immunoglobulin E measurement is a poor predictor of allergies or asthma.1

Specific serum IgE testing

Among children aged 1–4 years attending primary care, those with raised specific IgE for inhaled allergens (e.g. house dust mite, cat dander) are two-to-three times more likely to have asthma at age 6 than non-sensitised children.1 Sensitisation to hen’s egg at the age of 1 year (specific IgE) is a strong predictor of allergic sensitisation to inhaled allergens at age 3 years.1

Bronchial provocation (challenge) tests in children

Clinical assessment is more sensitive for confirming the diagnosis of asthma than tests for airway hyperresponsiveness.

The main roles of bronchial provocation (challenge) tests of airway hyperresponsiveness (airway hyperreactivity) are to confirm or exclude asthma as the cause of current symptoms, including exercise-associated respiratory symptoms such as dyspnoea or noisy breathing. 67

Challenge tests are performed in accredited lung function testing laboratories. These tests are usually difficult to perform in children under 8 years of age because they involve repeated spirometry tests.

If challenge testing is needed, consider referring to a paediatric respiratory physician for investigation, or discussing with a paediatric respiratory physician before selecting which test to order.

Do not test during a respiratory infection, or initiate inhaled corticosteroid treatment a few weeks before challenge testing, because these could invalidate the result.

Bronchial provocation tests of airway hyperresponsiveness include:

  • exercise challenge test8
  • mannitol challenge test910
  • methacholine challenge test.11, 12
Roles of other lung function tests in diagnosing asthma in children

Peak expiratory flow meters in asthma diagnosis

Variability in lung function based on serial home measures of peak expiratory flow and FEV1 shows poor concordance with disease activity in children.3

Using a peak flow meter to measure peak expiratory flow in children does not reliably rule the diagnosis of asthma in or out.3

Newer tests under investigation

Impulse oscillometry, tests of specific airways resistance, and measurements of residual volume are being investigated for use in asthma diagnosis and management,13, 14 but their availability is mainly restricted to specialist and research centres.3

Cardiopulmonary exercise challenge test

Cardiopulmonary exercise (stress) testing may be appropriate to assess cardiopulmonary fitness and identify respiratory or cardiac limitation of exercise in children presenting with exercise associated respiratory symptoms such as dyspnoea or noisy breathing.

Further investigations in children: 0–5 years

In preschool children, further investigations (other than allergy tests) are not necessary and are generally not helpful.1

Investigations in a preschool child may be justified in any of the following circumstances:1

  • symptoms are present from birth
  • airway obstruction is abnormally severe
  • recovery is very slow or incomplete (resulting in prolonged or repeated hospital admission in the first few years of life)
  • episodes continue in the absence of a viral infection
  • when parents are very anxious.
Further investigations in children

Microbiological investigation

Microbiological investigations are not routinely recommended in children because the result does not alter management decisions, even though respiratory viruses can be identified.1

However, it may be useful to identify the virus in atypical cases (e.g. children with severe viral infections or Mycoplasma infections).

Chest X-ray and other imaging technologies

Chest X-ray should be ordered when a child’s symptoms and signs suggest an alternative diagnosis that can be identified or ruled out by X-ray.

A chest X-ray will neither establish nor rule out a diagnosis of asthma.1

Exhaled nitric oxide testing

The exhaled nitric oxide test is not currently available as a standard clinical test and is mainly a research tool at present. Exhaled nitric oxide can be measured in unsedated children from the age of 3–4 years.3 Standardised reference values are available for children aged 4 years and older.1

Specialised investigations in children

Induced sputum

The sputum test for airway inflammation is not used in clinical practice.

Higher sputum eosinophil counts are associated with more marked airways obstruction and reversibility, greater asthma severity and atopy. In children with newly diagnosed mild asthma, sputum eosinophilia is present and declines with inhaled steroid treatment.3

The use of induced sputum test in the investigation of wheezing syndromes in preschool children has not been studied.1

Sputum induction is feasible in most school-aged children, but it is technically demanding and time consuming, and at present remains a research tool.3

White cell count

Blood eosinophilia in children aged 0–5 is a poor predictor of later asthma when used alone.

In children aged over 5 years, the presence of eosinophilia (≥ 4%) increases the probability that wheeze is due to asthma.3

Blood eosinophil testing is a component of the Asthma Predictive Index.15 However, this test is not routinely recommended because the Asthma Predictive Index has only limited clinical value in predicting whether a wheezing preschool child will have asthma at school age.1, 16

Invasive tests

Airway wall biopsy and bronchoalveolar lavage are invasive investigations. These should only be used in unusual cases, and must be performed in specialised centres.1



  1. Brand PL, Baraldi E, Bisgaard H, et al. Definition, assessment and treatment of wheezing disorders in preschool children: an evidence-based approach. Eur Respir J. 2008; 32: 1096-1110. Available from:
  2. Dweik RA, Boggs PB, Erzurum SC, et al. An Official ATS Clinical Practice Guideline: Interpretation of Exhaled Nitric Oxide Levels (FeNO) for Clinical Applications. Am J Respir Crit Care Med. 2011; 184: 602-615. Available from:
  3. British Thoracic Society (BTS), Scottish Intercollegiate Guidelines Network (SIGN). British Guideline on the Management of Asthma. A national clinical guideline. BTS, SIGN, Edinburgh, 2012. Available from:
  4. Global Initiative for Asthma (GINA). Global strategy for the diagnosis and management of asthma in children 5 years and younger. GINA, 2009. Available from:
  5. Australasian Society of Clinical Immunology and Allergy (ASCIA), Skin Prick Testing Working Party. Skin prick testing for the diagnosis of allergic disease: A manual for practitioners. ASCIA, Sydney, 2013. Available from:
  6. Anderson SD. Bronchial challenge tests: usefulness, availability and challenges. Breathe. 2011; 8: 53-60. Available from:
  7. Cockcroft DW. Direct challenge tests: airway hyperresponsiveness in asthma: its measurement and clinical significance. Chest. 2010; 138(2 Suppl): 18S-24S. Available from:
  8. Anderson SD, Pearlman DS, Rundell KW, et al. Reproducibility of the airway response to an exercise protocol standardized for intensity, duration, and inspired air conditions, in subjects with symptoms suggestive of asthma. Respir Res. 2010; Sept 1: 120. Available from:
  9. Barben J, Roberts M, Chew N, et al. Repeatability of bronchial responsiveness to mannitol dry powder in children with asthma. Pediatr Pulmonol. 2003; 36: 490-4. Available from:
  10. Kersten ET, Driessen JM, van der Berg JD, Thio BJ. Mannitol and exercise challenge tests in asthmatic children. Pediatr Pulmonol. 2009; 44: 655-661. Available from:
  11. Liem JJ, Kozyrskyj AL, Cockroft DW, Becker AB. Diagnosing asthma in children: what is the role for methacholine bronchoprovocation testing?. Pediatr Pulmonol. 2008; 43: 481-9. Available from:
  12. Carlsten C, Dimich-Ward H, Ferguson A, et al. Airway hyperresponsiveness to methacholine in 7-year-old children: sensitivity and specificity for pediatric allergist-diagnosed asthma. Pediatr Pulmonol. 2011; 46: 175-178. Available from:
  13. Child F. The measurement of airways resistance using the interrupter technique (Rint). Paediatr Respir Rev. 2005; 6: 273-7. Available from:
  14. Oostveen E, MacLeod D, Lorino H, et al. The forced oscillation technique in clinical practice: methodology, recommendations and future developments. Eur Respir J Supplement. 2003; 22: 1026-41. Available from:
  15. Castro-Rodriguez JA. The Asthma Predictive Index: a very useful tool for predicting asthma in young children. J Allergy Clin Immunol. 2010; 126: 212-216. Available from:
  16. Savenije OE, Kerkhof M, Koppelman GH, Postma DS. Predicting who will have asthma at school age among preschool children. J Allergy Clin Immunol. 2012; 130: 325-331. Available from: