Asthma in Preschool Children: Difficult to Diagnose and Difficult to Treat.

It is important to diagnose and manage asthma correctly in preschool children. It is unfortunately also very difficult to diagnose and manage asthma correctly in preschool children.

Asthma results from episodes of narrowing of the airways in the chest. These episodes are usually associated with chest tightness, breathlessness, wheezing and cough. Wheezing occurs commonly in young children and it is not unique to asthma. Up to 50% of all children will suffer from at least one episode of airway narrowing and wheeze before they turn 5 years old. There are many reasons why preschool children may suffer from a wheezy chest. All preschool wheeze is not asthma and wheeze therefore poses frequent diagnostic and management challenges to doctors and to parents.

True asthma often begins in early life.  It is the most common chronic childhood disease. Uncontrolled asthma can contribute significantly to the suffering of young children. It can also be very well controlled if it is correctly diagnosed and managed. The challenge to doctors is to be skilled at correctly selecting the asthmatic child from the population of preschool wheezy children, and to then offer effective management.

When is it asthma?

Asthma is caused by chronic inflammation of the airway. The inflammation makes the airway overly sensitive, or hyperresponsive, to various triggers that again lead to asthma attacks. Lung function tests are used to detect airway hyperresponsiveness in older people. Young children cannot perform these tests. To document airway inflammation requires invasive techniques that are seldom practical to perform. The symptoms of asthma in young children vary a lot and can easily be confused with the symptoms of other lung diseases. Doctors are therefore forced to embark on a process of “adding evidence” to “build” a diagnosis, often over time, in order to come to a reasonable conclusion. The diagnosis of asthma in preschool children must be based on a combination of findings and not on a single test or episode. Different features in the disease history, clinical examination and some special tests can be helpful in adding evidence to a correct diagnosis of preschool asthma.

History-taking is the most valuable diagnostic instrument. Recurrent episodes of wheeze are the most common symptom associated with preschool asthma. Wheeze is unfortunately one of a number of many types of noisy breathing. It is often misunderstood by parents and by healthcare workers. Proper history-taking should confirm true wheeze as a presenting symptom. History-taking should also focus on the time and pattern of the wheeze episodes. Episodes of wheeze that presents, or persists, after the age of 3 years will favour asthma as the more likely diagnosis. The onset of wheeze at a younger age, and especially in babies, should warn against other possible reasons for the wheeze. Asthma occurs more commonly in children with a family history of allergy. The presence of allergy, especially at a young age, will increase the likelihood of asthma. History-taking should further aim at identifying possible asthma trigger factors. Common airway virus infections, like the common cold, may trigger acute asthma episodes in asthmatic children. They are on the other hand also often the reason why a younger child may wheeze without being asthmatic. It is therefore helpful to specifically determine if wheeze symptoms are also present in the absence of airway infections. Exercise-induced wheeze or cough, and wheeze or cough at night, in the absence of an airway infection, adds evidence to a likely asthma diagnosis. Wheeze that responds to inhaled bronchodilator therapy will further support possible airway hyperresponsiveness and an asthma diagnosis.

The clinical examination does not always offer much help in diagnosing preschool asthma. It can be of value if the clinical features of airway narrowing are present at the time when you visit the doctor, and especially if these signs improve after the administration of inhaled bronchodilator therapy. The presence features of allergic disease, like allergic rhinitis and allergic eczema, also add support to an asthma diagnosis. The true value of a proper clinical examination often lies in making sure that other illnesses are not causing the wheezy episodes.

No special test can diagnose asthma with certainty in preschool children. Patients with suspected asthma, and especially when long term asthma treatment is considered, should be tested for allergy. Skin prick tests are preferred to blood tests when looking for allergic sensitisation. Other special tests remain a matter of clinical judgement by the doctor and are aimed at excluding other reasons of preschool wheeze. Such tests are justified when symptoms are present from birth or infancy, are abnormally severe with slow or incomplete recovery, leads to repeated and prolonged hospital admission, continue in the absence of viral airway infections and in cases when parents are very anxious.

A therapeutic trial of asthma medication may provide guidance to the presence of asthma. The trial should include inhaled cortisone (ICS) and the as needed inhalation of bronchodilators for 8-12 weeks. A marked improvement during the treatment, and again deterioration when it is stopped after 8-12 weeks, will add support to an asthma diagnosis. The use of ICS should be terminated if a clear response to treatment is not demonstrated.

There are different types of asthma in preschool children

Several types of wheeze and asthma have been recognised in preschool children. It is important to identify the type of asthma that a young child may suffer from. The different types may require different treatment combinations and some types also outgrow sooner than others.

Treating asthma in preschool children.

Asthmatic children and their care-givers should receive a comprehensive treatment plan. May aspects like the use of medication, environment control, education and emergency management should be discussed.

Medicine remains the cornerstone of treatment. Cough syrups, antihistamines, syrups that reduce mucus production and syrups that open the airway are seldom of any value.  Inhaled medications are the most effective. Different delivery devices, or spacers, are used in combination with asthma sprays or pumps to ensure the effective delivery of the medication to the lungs. These spacers must always be used. The most effective spacer, that meets the patient’s needs, must be selected for every individual patient.  It does not help to take the correct medication if it is not also correctly administered. The use of asthma pumps and spacers offer various advantages over nebuliser treatment. The initial dosing and combination of medications will depend on the severity of asthma at the time of the diagnosis and on the type of asthma that the child suffers from.

Asthma is a chronic disease. The level of asthma control, with appropriate adjustment of treatment levels, must be done on a regular basis in order to find the lowest medication doses that effectively control the asthma symptoms. Asthmatic children should visit their doctor at least three times a year. Children often outgrow their asthma and a failure to adhere to regular follow-up visits often leaves children on treatment for longer than needed. 

It is difficult to correctly diagnose and effectively treat asthma in preschool children. A correct diagnoses and an effective treatment plan offers high reward for the children and their parents.


Dr André van Niekerk.

Paediatrician and Paediatric Pulmonologist.

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