A study of Western Red Cedar sensitivity: workers' allergy reactions and symptoms.

In 154 individuals who work with Western Red Cedar in Japanese wooden frame factories a high incidence (24.7%) of bronchial asthma was observed. A positive intradermal test was found in 89% of the asthmatics and in 56% of all. A highly positive inhalation test was obtained only in the asthmatic group. It is suggested that other symptoms in addition to bronchial asthma might be caused by Western Red Cedar because of the frequency of positive skin reactions to the Western Red Cedar antigen.