Recent epidemiologic evidence has challenged the paradigm suggesting a direct causal relationship between allergic sensitization and asthma.

We sought to investigate the role of a familial predisposition for asthma in the development of atopy in children.

Subjects were participants in the Tucson Children's Respiratory Study. Skin tests to aeroallergens were performed in parents and in children at ages 6, 11, and 16 years. Parents were considered asthmatic if they reported physician-confirmed asthma. Parents were divided into 4 phenotypes on the basis of skin sensitization (Skt+ or Skt−) and asthma status (As+ or As−): Skt−/As−, Skt−/As+, Skt+/As−, and Skt+/As+.

Children's allergic sensitization differed among parental phenotypes at all ages (P < .0001). Children in the Skt+/As− and Skt+/As+ groups were significantly more likely to be allergic than children in the Skt−/As− group at all ages. Among children with allergic parents, those with at least one parent with asthma were significantly more likely to have positive skin test responses than those with nonasthmatic parents at age 6 years (52.4% vs 37.4%, P < .005) and 11 years (70.1% vs 55.6%, P < .005) but not at age 16 years (82.3% vs 75.1%, P = .180). Results were independent of wheezing in the child and of the characteristics of atopy in parents. The Skt−/As+ group had too few subjects for meaningful comparisons.

Among children of atopic parents, parental asthma is a risk factor for allergic sensitization in early childhood. The strong association between allergic sensitization and asthma is at least in part explained by an increased susceptibility to allergen sensitization in subjects predisposed to asthma.