Neonatal birch‐pollen contact and subsequent allergy to birch pollen

Abstract

It is shown by regression analysis that the risk of immediate hypersensitivity to birch pollen, as measured by a skin test, is positively correlated with the quantity of birch male flowers and the number of non-rainy days in the first birch flowering season (May) met in infancy. The risk is also dependent on the month of birth, with maximal risk associated with birth between Feb.-April. Early pollen contacts, particularly during the first 6 mo. of life, apparently increase the risk of pollen allergy for a period of 20 yr. Elimination of early birch pollen contacts could reduce the prevalence of immediate hypersensitivity to birch by 28% in the 0-19 yr age group.