Nejm 1995;333:107

Cause:Cotton dust bacterial endotoxin in byssinosis (Nejm 1987;317:805), hemp and flax dust, redwood sawdust, isocyanates, castor bean dust, etc. Occupational airborne exposures in factories that process raw products

Pathophys:Acute pulmonary bronchoconstriction starts on 1st workday of the week; later in the disease course, sx’s persist further into the week. Occupational asthma is in contrast to allergic alveolitis caused by actinomycetes and rarely other fungi where predominant inflammation is in alveoli; mill fever may be a variant of allergic alveolitis; nylon flock workers lung (Ann IM 1998;129:261)

Very common, esp in cotton mill carding rooms where 70% of all workers will react within 1 yr of employment, 40-50% develop sx

Sx:Tight chest, dyspnea, cough for a day or 2 after a weekend off or other rest. Fever with mill fever

Si:Decreased ventilation capacity during the workday

Progressive bronchospasm may lead to irreversible obstruction

Pulmonary hypertension; severe COPD, even if leave work (Ann IM 1982;97:645)

Lab: PFTs:Decreased FEV₁/FVC

Xray:Chest often normal, or shows hyperinflation

Rx: Prevent by improving dust removal. Pre- and post-Monday work FEV₁ checks of sx, inhaled bronchodilators; avoid dust