Natural history of allergic diseases in children.

Questionnaire data from 1335 14-year-old children with a history of past or present asthma, allergic rhinitis or eczema were analysed regarding age at onset and cessation of symptoms. Incidence of asthma and eczema was highest during the first years of life. Early incidence of asthma was higher in boys than in girls but the sex ratio equalized gradually during childhood. Early incidence of eczema was equal between the sexes but the proportion of girls increased gradually with later age at onset. In 24% of the children more than one symptom was found. Cessation of symptoms was common in asthma (55%), in particular in those with early onset (74%), but less common in eczema (34%). Cessation of symptoms was less common in both diseases when associated with other allergic symptoms. Incidence of allergic rhinitis was fairly constant during childhood and cessation of symptoms was uncommon. A high risk of allergic airways disease was found after early eczema.