(See also Overview of Environmental Pulmonary Disease.)
Byssinosis occurs almost entirely in workers who contact unprocessed, raw cotton, especially those who are exposed to open bales or who work in cotton spinning or in the carding room. Byssinosis can occur after acute exposure but usually occurs in workers with a history of chronic exposure of a least 10 years.
Evidence suggests that the cause is bacterial endotoxin in the cotton dust. The endotoxin leads to bronchoconstriction, chronic bronchitis, and gradual decreases in pulmonary function, particularly in genetically susceptible people. Prolonged exposure to cotton dust was once thought to cause emphysema, a theory now disproved.
Symptoms are chest tightness and dyspnea that lessen with repeated exposure. Symptoms develop on the first day of work after a weekend or vacation and diminish or disappear by the end of the week. With repeated exposure over a period of years, chest tightness tends to return and persist through midweek and occasionally to the end of the week or as long as the person continues to work. This typical temporal pattern distinguishes byssinosis from asthma.
Signs of acute exposure are tachypnea and wheezing. Patients with more chronic exposure may have crackles.
Diagnosis of byssinosis is based on history of exposure to raw cotton and pulmonary function tests that show typical airflow obstruction and a reduction in vital capacity, especially if measured at the start and end of a first work shift. Hyperresponsiveness to methacholine is also often observed.
Surveillance measures, including symptom reporting and spirometry in textile workers, can aid in early detection.
Treatment of byssinosis includes avoidance or reduction of exposure and use of asthma drugs.
Use of personal protection and adherence to environmental hygiene is critical to the prevention of byssinosis (1).