Between 1992 and 2000 allergy skin prick tests (SPT) were performed on 2,124 children suspected of having respiratory allergic diseases. Previous studies showed that grass pollen was the most frequent allergen (32.8%), while ragweed allergy occurred in 24% of children.

In this study children who produced a positive reaction to tree or weed pollen mixtures were investigated by SPT to other aero-allergen pollens (Bencard allergens), including tree pollens (471 children) and weed pollens (476 children). 22% of the tested children reacted to at least one tree pollen.

Between 1992 and 2000 the frequency of reactivity to ash pollen increased from 3% to 11%, and to birch pollen, from 3.6% to 10.7%. In 2000, all trees produced a positive skin reaction in at least 7% of the 2,124 children. The prevalence of allergy to maize and rye was constant (13.7%) during the investigated years, whereas reactivity increased from 6% to 16%, almost always (254 cases) associated with ragweed allergy. 22% of the investigated children were allergic to at least one tree pollen, most commonly ash (11%) and birch (10.7%).

The clinical importance of tree pollen allergy in Hungary is less than in northern Europe, but weed allergy is rapidly increasing related to mugwort and ragweed.