Effects of histamine aerosol in byssinotic subjects.

The changes in symptoms and lung function tests of 26 cotton cardroom workers were investigated before and after inhalation of histamine aerosols. Three subjects with no chest symptoms and 11 with uncomplicated byssinosis showed no evidence of any pulmonary reaction, but 12 bronchitic byssinotic subjects showed evidence of the pulmonary hypersensitivity found in patients with chronic bronchitis alone. These findings cast doubt on the possible role of non-antigenic histamine liberators in the mechanism of production of `return-to-work' tightness in byssinosis.