Using Tests in Preschool Children With Wheeze to Determine the Need for Inhaled Corticosteroid Therapy.

Peripheral blood eosinophil count will be measured from a finger prick blood sample, using the Haemocue machine, allowing a result in approximately 2 minutes. The test will allow to assess the presence or not of eosinophilia and if it can predict future wheezing exacerbations and response to inhaled corticosteroids (ICS).

Skin prick tests will be performed to: (a) house dust mite, (b) grass pollen, (c) tree pollen, (d) cat hair, (e) dog hair, as well as normal saline and histamine which will act as negative and positive controls respectively. In addition, skin prick tests will allow the assessment of which aeroallergen is the most useful predictor of outcomes in preschool children.

The child will breathe normally into a sample bag that will be collected for later analysis of FeNO levels. The test will be performed twice.