The clinical spectrum of humidifier disease in synthetic fiber plants.

In a synthetic fiber production site with recirculating cold water humidification systems and small-size-particle (> 0.1 mu < 1 mu) oil mist exposure, humidifier disease was diagnosed in several workers. The patients could be divided into three groups illustrating the clinical spectrum of humidifier disease: humidifier fever (toxic inhalation fever) (12 patients): an asthma-like syndrome (8 patients); and allergic alveolitis (4 patients). Natural challenge at the work place, monitored by parameters such as peak-flow, spirometry, blood leucocyte count, and body temperature, provided important diagnostic information. In patients with chronic allergic alveolitis, a gradual recovery during an exposure-free period indicated a work-related causation, more than changes during challenge in normal work. In some patients, the fungus Sporothrix schenckii, hitherto unknown as a sensitizer, may have been at least one of the causative antigens. Measured levels of viable fungi (< or = 100 CFU/m3) and endotoxin (64 pg/m3) in air samples were much lower than those at which health effects usually are reported. Small-size-particle oil mist exposure may have underestimated the exposure to microorganisms, but otherwise an adjuvant role to this type of co-exposure might also be postulated. In contrast to allergic alveolitis, the asthma-like syndrome appeared to be more common in patients with a history of atopy and of smoking.