Is the prevalence of atopy increasing?

There is controversy about whether allergic disease has increased in recent decades. This study compared the prevalence of atopy, as shown by allergy skin prick testing among adults in 1988 (n = 74) with a similar study carried out in 1974 (n = 1359). Both study groups were drawn from the general population in south west London, but the 1988 sample specifically excluded people with rhinitis. The proportion of subjects with at least one positive reaction to a panel of three common allergens increased significantly from 23% in 1974 to 46% in 1988 (P less than 0.01). If allowance was made for the exclusion of rhinitis subjects from the 1988 sample, the current prevalence of atopy may be higher still. The increase in prevalence was significant in older subjects (aged 55-59 years) and women but not in other age groups or in men. This small study raises the possibility that atopy has increased in prevalence in the UK over recent decades and additional studies are needed to evaluate the validity of this hypothesis.