Treatment approaches: symptom-based treatment
The 2008 European Respiratory Society Task Force proposed dividing pre-school wheezers into EVW and “multiple trigger (MTW)” wheeze [3]. Both EVW and MTW were characterised by symptoms present only with a (usually clinically) diagnosed viral respiratory tract infection, but in MTW there were also symptoms between viral infections, triggered by, for example, exposure to allergens to which the child was sensitised, and excitement. It was made clear that EVW was not the same as transient wheeze, and could persist beyond school age, and MTW was not the same as persistent wheeze, and could be transient. Furthermore, it was clear that the pattern of wheeze could change spontaneously over time, and with treatment (MTW treated with ICS could present as EVW). MTW was often but not exclusively associated with atopic disease and allergen sensitisation, whereas EVW was usually not. Intermittent therapy was the recommendation for EVW, whereas children with MTW were considered for continuous ICS therapy. However, the obvious weaknesses of this approach are that there is heavy reliance on parental reporting of symptoms, and the underlying endotype was not even considered, let alone measured. The 2012 update [41] recognised the reliance on parental reporting and recommended that an N-of-1 trial of ICS was reasonable in EVW if symptoms were very severe or parental under-reporting of symptoms was suspected but discontinuing if there was no benefit. However, there was still no attempt to tailor treatment to underlying pathology, and it should also be said that just because symptoms are severe is not a reason to try a treatment which does not work! Proposed treatment algo rhythms have been published, but these remain symptom based [47].
However, when symptom pattern is compared to pathology, it was very clear that both EVW and MTW could have BAL eosinophilia or a normal BAL, and atopy was also not predictive of BAL findings [48]. This may reflect the difficulties of symptom perception and recall by parents. Whatever the reason, it became increasingly clear that history taking is an inadequate guide to treatment.