Hay fever, hygiene, and household size.

Abstract

Hay fever has been described as a "post industrial
\nrevolution epidemic,"' and successive morbidity
\nsurveys from British general practice suggest that its
\nprevalence has continued to increase over the past 30
\nyears.) Other evidence suggests a recent increase in the
\nprevalence of asthma2 and childhood eczema.3 This
\npaper suggests a possible explanation for these trends
\nover time.