Horse chestnut (Aesculus hippocastanum) pollen: a frequent cause of allergic sensitization in urban children

We investigated the incidence of allergic sensitization and the risk factors underlying sensitization in 214 urban children exposed to horse chestnut pollen. By means of the Phadezym RAST, we found IgE specific to horse chestnut pollen in 12.6% of the urban children, whereas it occurred in only 1.9% of control subjects recruited from a rural area. Reports of allergic symptoms in spring during the horse chestnut pollen load coincided with the presence of specific IgE in 5.1% of the urban group as against 1.4% of that recruited from the rural area. Environmental factors other than those related to urban living and higher horse chestnut pollen counts had no significant impact on allergic sensitization. Increased total IgE levels (> 100 kU/1), however, and the sensitization to pollen of other species significantly raised the odds for sensitization to chestnut pollen. They were highest in highly atopic children with sensitization to pollen, especially to that of plane trees (OR = 73.9). These results suggest the relevance of horse chestnut pollen because of the high allergic sensitization rate among urban children, and they should also be borne in mind when it comes to the planting of trees in urban areas.