Epidemiology of the allergic diseases: are they really on the increase?

Epidemiological studies on representative populations clearly demonstrate a significant general increase of atopic diseases during the last decades, mainly for pollinosis. For the manifestation of an atopic disease both allergen exposure, which leads to specific IgE antibody formation, and the presence of additional realization factors are required. The nature of the latter is still partially unknown. Careful interpretations of clinical and experimental observations show that besides indoor and outdoor pollution, increased exposure to allergens through changes in human way of living is an important cofactor responsible for the increased incidence of atopic diseases.