[Local differences of oral allergy syndrome with pollinosis--a comparison between Hanshinkan and Higashiharima in south Hyogo].

BACKGROUND

A number of cases of oral allergy syndrome (OAS) to fruits with birch pollinosis have been described. The antigen of Alnus sieboldiana (alder) trees which are massively planted on Rokko Mountain appeared to be highly similar to birch pollen.

METHODS

We took the medical history of pollinosis and OAS, measured pollen-specific IgE (CAP-RAST) and performed prick tests of causative fruits to the outpatients of the two hospitals in different areas.

RESULTS

In Hanshinkan district, at the foot of Rokko Mountain, we experienced 9 cases of OAS among 377 outpatients. All 9 cases had alder specific-IgE. The prevalence rate of OAS was 11.0% in the alder specific-IgE-positive patients and 0% in the alder specific-IgE-negative patients in the area. On the other hand, in Higashiharima district where less alder trees exist and further from Rokko Mountain, 19 OAS patients were documented among 2000 outpatients. Six of the 19 patients with OAS did not have alder specific-IgE. The prevalence rate of OAS was 6.8% in the alder specific-IgE-positive patients and 11.8% in the mugwort specific-IgE-positive patients in the area.

CONCLUSIONS

In Hanshinkan, alder pollinosis seems to be most important for the cross reactivity to the OAS. In Higashiharima, mugwort pollinosis may be more important than alder pollinosis for the cross reactivity to the OAS.