Provocation tests in extrinsic allergic alveolitis in mushroom workers.

The clinical diagnosis of extrinsic allergic alveolitis can be supported by a positive provocation test. Twenty-eight common mushroom (Agaricus bisporus) workers, 4 oyster mushroom (Pleurotus ostreatus) workers and 6 Shii Take mushroom (Lentinus edodes) workers, whose medical history indicated a possible extrinsic allergic alveolitis, were examined. The provocation test consisted of a control day, an exposure day, and half a day of follow-up observation. On the control and exposure days, the body temperature, leucocyte count and lung function were measured every 2 h. The chest X-ray and arterial blood gas sample were taken once. The exposure consisted of a 1-h presence on the common mushroom farm in spawning conditions or inhaling a suspension of spores of Pleurotus or Shii-Take in the laboratory. Eighteen of the 28 people employed on the common mushroom farm, all 4 Pleurotus workers and 4 of the 6 Shii-Take workers were diagnosed as having extrinsic allergic alveolitis, according to the following criteria: a positive history and 2 or more of the following findings: increase in leucocyte count, rise in temperature and decrease in inspiratory vital capacity (IVC) and total lung capacity (TLC).