Clinical manifestations of Japanese cedar pollinosis: an epidemiological study.

In an investigation of the clinical features of Japanese cedar pollinosis in Toyama Prefecture, Central Japan, an epidemiological study was carried out in 1991 by means of questionnaires. There were 1,720 female and 1,163 male patients, a total of 2,883 patients. In both female and male patients, the highest incidence was found in those in their thirties. The most frequent onset was 19th March 1991, when the maximum number of air-borne pollen was detected and also the highest temperature in March was recorded. The 236 patients in the children's group ranged in age from 5 to 15 years, and the number of male children was greater than that of female. The number of patients tended to increase only gradually up to the age of 11 years, and then rapidly from 12 to 15 years of age. The greatest number of patients developed symptoms at the age of 10 years. HD-RAST positivity was definitely higher in the children group than in the adult group. No significant association was found between the age of development of symptoms and HD-RAST positivity.

[Characteristics of pollen scattering from male sugi flowers in relation to occurring of symptoms in Japanese cedar pollenosis patients].

Generally, airborne scattering of sugi (Cryptomeria japonica D. Don) pollen begins to be observed coincidentally with the flowering of the male sugi flowers between February and April. However the male sugi flowers disperse a certain amount of pollen in early January, only small levels of which can be detected with a Durham's sampler. In some Japanese cedar pollinosis patients, allergic symptoms have been reported to occur in early January. Among 1,366 Japanese cedar pollinosis patients studied, 265 have experienced allergic symptoms before the first day of pollen scattering as determined with a Durham's sampler. Accordingly, it is suggested that substantial amounts of sugi pollen are scattered from early January, and that clinical symptoms can be induced in highly sensitive Japanese cedar pollinosis patients from early January, even before the flowering of sugi.

[Relationships between the pollen productions in sugi (Cryptomeria japonica D. Don) forests and the patterns of atmospheric scattering pollens in Toyama Prefecture--the example of Toyama Prefecture in 1990].

We investigated the geographical distribution of sugi (Cryptomeria Japonica D. Don) forests and the male flower-setting conditions of them in Toyama prefecture. The relationships between our findings and the atmospheric pollen scattering patterns were also studied. The results were as follows. 1. Atmospheric pollen counts and their scattering patterns were fairly easily explained by the geographical distribution of 30-year old sugi forests, the male flower-setting conditions and the first day pollen was scattered in those forests. 2. Total atmospheric counts and maximum sugi pollen peaks were significantly affected by the proximity of sugi forests at altitudes of less than 200 meter. 3. In the atmospheric pollen survey, the detected pollen counts decreased according to the distance between the observation sites and the sugi forests. And few pollen grains were observed from natural sugi forests growing at distances of 20 km to 30 km from the observation sites.