Table 1

 Characteristics of study subjects

NO, nitric oxide.
No subjects required treatment with inhaled corticosteroids before the pollen season.
Mean (range) age (years)11.2 (7–16)
Mean (range) duration of asthma (years)4.2 (1–12)
Mean (range) duration of rhinoconjunctivitis (years)4.2 (1–12)
    Phleum pratense 44 (100%)
    Tree pollens11 (25%)
    House dust mite14 (32%)
Mean (range) dose of inhaled steroids during previous summer (μg beclomethasone equivalent)325 (0–800)
No (%) requiring long acting antihistamine41 (93%)
No (%) requiring long active topical nasal steroids21 (48%)
Median (range) number of pre-season exhaled NO readings5.0 (1–9)
Median (range) number of pollen season exhaled NO readings2 (1–3)