Testing for tree pollen hypersensitivity typically involves the use of several trees. Identifying patterns of cross hypersensitivity to tree pollens could reduce the number of trees used for testing. Sycamore is a common component of a regional tree pollen extract mixture used for allergy testing and treatment. The objective of this study was to investigate the cross-sensitivity and prevalence of sycamore pollen hypersensitivity in relation to hypersensitivity towards other tree pollens in the New York City area.

More than 380 patients predominantly with allergic rhinitis were serologically tested for IgE toward the prevalent tree pollens of the New York City area over the years from 1999 through 2003. Specific tree pollens that were examined included oak (Quercus alba), birch (Betula verrucosa), maple (Acer negundo), hickory (Carya pecan), ash (Fraxinus americana). and sycamore (Acer pseudoplatanus). Statistical analysis of the levels of hypersensitivity was performed to identify correlations and grouping factors for sycamore in relationship to the other trees.

Sycamore specific IgE was less prevalent than the other trees. In factor analysis, sycamore showed strong loadings in a factor which was dominated by maple, ash, and hickory. This factor was distinct from a second factor which loaded high with oak and birch. Strongest correlations were observed between sycamore and hickory. No sycamore allergic patients were identified who did not show hypersensitivity towards the other trees tested for.

Sycamore pollen hypersensitivity is not important in identifying tree pollen allergic patients in the New York City area.