Differential diagnosis of byssinosis by blood histamine and pulmonary function test: a review and an appraisal.

A study was conducted on byssinotic (N = 8) and nonbyssinotic (N = 16) mill workers exposed to cotton dust and on controls (N = 15) from a cotton dust-free zone. They were examined for chest tightness and breathlessness during successive days from Mondays to Fridays. In addition to monitoring the workers only on Mondays after shift work, their blood histamine levels and pulmonary function tests such as FEV1, PEFR, and FEF25-75% (PEFR represents airflow of larger airways, FEF25-75% reflects airflow in smaller airways, and FEV1 represents airflow in both central and peripheral airways) were screened, but Monday data were only counted to appraise a contrast between these two parameters. The results showed that the histamine levels were significantly higher in the cotton dust-exposed workers in association with significantly decreased FEV1, PEFR, and FEF25-75%, indicating bronchoconstriction of the central, larger, and peripheral airways. Histamine can cause a severe constriction of the central as well as peripheral airways in cotton dust-exposed workers, enabling a paradoxical effect for a differential diagnosis of byssinosis.