Professor Craig Mellis - Respiratory Paediatrician, The New Children's Hospital

The joys of parenthood can be easily dampened by the sound of a child who wheezes and coughs.

While concerned parents, particularly those with a family history of asthma, are quick to seek help, the challenge for us as practitioners is to differentiate between a cough and a wheeze while also taking into account a child's age. This, along with a good measure of caution, should lead to a more accurate diagnosis.

While it is a concern that there is still a small percentage of children with asthma who remain undiagnosed, it is of greater concern that, through professional zeal, a large number of children are being inappropriately labelled as having asthma.

Distinguishing a bronchitic cough from asthma

A child with recurring coughing illnesses, or one prolonged coughing illness, in the absence of wheeze or shortness of breath, is more likely to have infective bronchitis, or one of various winter viruses, as opposed to asthma. In such cases the child will not respond to asthma medication and the cough will persist. Unfortunately, this can lead to some children being put on increasing doses of treatment. In many children, the cough will go away in due course. If this outcome is incorrectly interpreted as a response to the medication it may in turn result in children being kept on medication they don't really need.

Diagnosing asthma in a child who does wheeze, but is less than twelve months old, should be done with great caution as the wheeze is more likely to be due to RSV bronchiolitis or anatomically small airways. In some infants the small airways are small enough to simply result in turbulent airflow (and wheeze) which will go away as the child grows.

While wheeze is less of a differentiator in the first year of life, diagnosis is easier once children are over two years of age, where persistent or recurrent wheeze points in the direction of asthma. Taking a 'wait and see' approach is the best option to avoid misdiagnosis in the under twos, when the presence of wheeze in this age group is most likely to be due to illnesses other than asthma.

'Treating' parental concerns

Once the question of whether a child has asthma or not is answered, the next area of concern for parents is treatment. By ensuring greater accuracy when diagnosing children we can help lessen the largely unfounded concerns of many parents about the side effects of long term usage of some treatments, particularly inhaled corticosteroids.

Inhaled corticosteroids can only be detrimental to children who don't need them, that is, children who are misdiagnosed as having asthma or those with mild asthma.

In children with genuine persistent asthma, and some with frequent episodic asthma, the risks involved from undertreatment are far greater than the treatment itself. For example, not being able to sleep because of undermanaged asthma interferes with a child's ability to concentrate and learn at school; persistent airway obstruction can lead to chronic lung damage; and not being able to participate in sport has both physical and psychological effects on a child.

While most parents concerned about inhaled corticosteriods are afraid of the drug's effect on a child's growth, children who need inhaled corticosteroids but who are not being treated with them, are more likely to be underweight, shorter, and have delayed puberty due to the effects of their asthma. Inhaled steroids were introduced twenty years ago at a time when children were undertreated or were on prednisone (an oral steroid) and growth suppression was common. Interestingly, these same children experienced a prompt return to normal growth patterns when placed on inhaled corticosteroids.

To use an analogy, it is virtually impossible for someone to become addicted to morphine if it is given to them when they have severe pain as the pain 'consumes' the drug. However, if given in the absence of severe pain, addiction is rapid. In the same way, inhaled corticosteriods appear to be poorly absorbed into the body ('consumed' in the airway) of a person who needs it to control their asthma.

When speaking to parents of children who need inhaled corticosteriods, it is important to emphasise that the growth suppressant effect of the disease is far greater than the potential for growth suppression from treatment. A child whose asthma is well controlled by inhaled corticosteroids will experience normal growth patterns.

Guidelines for good management

The asthma management guidelines are the result of years of clinical research and practice and for this reason all physicians should refer to them to determine the right medication for their asthma patients. While new treatments for asthma should always be considered, physicians should be wary about changing a stable patient's asthma plan.

A new class of drugs, known as leukotriene antagonists (LTAs) will soon be available in Australia. As they are in the form of a tablet they will no doubt appeal to consumers. However, the fact that they are systemic raises concerns about possible side effects and drug interactions, particularly with commonly used drugs like antihistamines and antibiotics. These side effects, even if they are remote (e.g one in 1000) will not necessarily be picked up in clinical trials and thus the ultimate role of these drugs will remain uncertain until more widely used.

From the little paediatric research currently available, which compares the drugs to placebo, the children most likely to benefit from LTAs are those with mild (frequent episodic) asthma who are on non-steroidal anti-inflammatory preventive medication such as Intal or Tilade. However the relative lack of good evidence at present suggests that if children are doing well on these non-systemic drugs then they should stay on them. These patients will not be able to 'do away' with puffers as they will still need to use a beta agonist aerosol. On this basis, it is highly unlikely that LTAs will replace inhaled corticosteroids in the treatment of children with persistent asthma.

As with any chronic disease in children, it is important for physicians to err on the side of caution before labelling a child asthmatic and then working through any concerns parents may have about the type or length of treatment recommended. While we continue to research preventative measures for asthma, it is important to get children stabilised on the right medication plan to ensure their asthma fits into, rather than takes over, their lives.

Content Updated July, 2001