Evolution of asthma through childhood.

The greatest incidence of childhood asthma is among males under 5 years, with decreasing numbers of new cases with age. Many young children wheeze, but remission is common especially in non-atopic children without a family history of allergy or asthma, whose wheezing relates more to infections and environmental tobacco smoke exposure. The prognosis of childhood asthma is best established from population studies, in which some two-thirds of wheezy children become symptom-free as adults, whereas follow-up studies of wheezing children seen in office or specialty clinic practice, who generally have more severe asthma, show a much greater likelihood (60-80%) of persistence of asthma into adulthood. Factors predisposing to persistence of childhood asthma include a positive family history, development of atopy, environmental exposures to allergens and cigarette smoke, markers of severity of childhood asthma, and female gender.