[Epidemiologic studies about the allergic diseases (author's transl)].

Three large epidemiological studies in Birmingham over a period of 20 years showed a significant increase in the prevalence of asthma in children. Children of immigrants from the West India and Asia had a low prevalence if born abroad, but as high a prevalence as European Children if born in England. The age of onset of asthma and eczema is earlier than that of maximum appearance of skin reactions to common allergens. Among atopic children, 35% have raised levels of IgG4. These children respond poorly to cromoglycate and usually need steroids. Those with eczema have high levels of both IgG4 and IgE. Asthmatic children are more frequently born between May and October compared with the general population. This excess of birth of asthmatic children in Summer is due to mite sensitive children. The excess of births in Summer is not related to hay fever or to pollen sensitivity.