Practical approach to managing exercise-induced asthma in children and adults

with asthma made worse by exercise, which is a common phenomenon. However, true exercise-induced asthma, where symptoms only occur in response to physical activity, is relatively uncommon. The mistake to make in this consultation would be to concentrate exclusively on the exercise-induced symptoms whereas, in reality, the situation encompasses many of the important general themes that are current in asthma care across most societies. Firstly, this is a call to return to the basics of asthma management. If her asthma hasn’t been reviewed for 18 months, then she had a diagnosis made when she was no older than 81/2 years of age. Although there is published evidence that spirometry can be accurately assessed from age 5 years onward, in real-life practice objective measurement of lung function using spirometry or peak expiratory flow (PEF) monitoring is difficult in young children. It is worth reviewing how the diagnosis was made – whether she had a positive response to treatment that was sustained over time, and whether withdrawal of her inhaled corticosteroid (ICS) led to a return of symptoms. In addition, family and personal history of atopy, and the presence of characteristic diurnal symptoms, any deterioration in response to viral, irritant or allergic triggers, and the presence of high pitched rhonchi (or wheeze) on auscultation whilst symptomatic would be useful pointers to a diagnosis of asthma. In addition to reviewing the diagnosis, this consultation is an opportunity to check both her concordance with therapy (cross referencing her statements with her prescription records) and her inhaler technique. The clinical difficulty now is that our patient is established on regular ICS therapy, making it much more difficult to demonstrate obstructive lung function or diurnal variation, or indeed a fall in PEF in response to triggers. Nonetheless, she should be taught how to use a PEF meter, checking her technique and her understanding of how to document the result, and she should be asked to keep a record for a minimum of two weeks, including not only morning and evening pre-bronchodilator recordings, but also any recordings when symptomatic, particularly relating to exercise. Ideally we should obtain a post-bronchodilator (20-30 minutes) reading following on from an exercise-induced fall in value. A change of 12% would be significant, although it is worth noting that a failure to bronchodilate does not exclude asthma. Another way of establishing exercise-induced symptoms and bronchoconstriction would be to arrange a supervised exercise session (for example in the surgery or pulmonary function laboratory), using either a simple step, or the more complex incremental shuttle walk/run. Ideally, this should take place in a safe environment, where a deterioration in the girl’s condition can be monitored and treated. Breathing cold air (never difficult to arrange in the North East of Scotland! ) is likely to result in even more effective bronchoconstriction. Ninety percent of people with asthma are affected by exercise, and exercise induces asthma symptoms in 35-45% of people with allergic rhinitis. Even when these two patient groups are excluded, however, there is still a 3-10% incidence of exercise-induced asthma in the general population. This distinction is important when it comes to treatment. In a true case of isolated exercise-induced asthma, it is reasonable to prescribe only a short acting β2-agonist, taken (where possible) in anticipation of the event, or to relieve symptoms. Where more conventional asthma is being triggered by exercise, a formal assessment of asthma control using a validated tool such as the Children’s Asthma Control Test will help guide treatment choices. Exercise bronchodilation can then be superimposed onto this regime. In our patient, there may be a role for giving her a long-acting