Markers of oxidative stress are increased in exhaled breath condensates of children with atopic dermatitis.

Background  Airway inflammation may be present in subjects affected by atopic dermatitis (AD) but still without asthma symptoms. Exhaled breath condensate (EBC) reflects the composition of bronchoalveolar extracellular lining fluid that contains a large number of mediators of airway inflammation and oxidative damage. Objectives  We assessed inflammatory markers in the EBC of patients with AD. Fifty-six children (34 girls and 22 boys) were enrolled: 33 affected by AD and 23 healthy controls. Methods  EBC was collected using a condenser device. We measured EBC pH and concentrations of leukotriene B4 (LTB4), 8-isoprostane, H(2) O(2) , malondialdehyde and 4-hydroxynoneal. Respiratory resistance was also evaluated. Results  EBC pH in patients with AD was significantly lower than in healthy children, median (range) being 8·02 (7·94-8·12) in AD vs. 8·11 (8·05-8·16) (P = 0·02). The values of exhaled 8-isoprostane and LTB4 were significantly increased in subjects with AD compared with normal controls (P < 0·01 and P < 0·001, respectively). There was increased 4-hydroxynoneal in patients with AD but this did not reach statistical significance. Evaluating respiratory resistance, no bronchoreversibility was demonstrated in the children with AD. Conclusions  pH, LTB4 and 8-isoprostane in EBC could be sensitive markers of airway inflammation in children with AD. Prospective studies would be of interest to evaluate if airway inflammation, not yet clinically evident, could predict the development of asthma later in life in children with AD.