Farmer's lung

Farmer's lung
Classification and external resources
Specialty
ICD-10	J67.0
ICD-9-CM	495.0
DiseasesDB	29636
eMedicine	med/771
Patient UK	Farmer's lung
MeSH	D005203

Farmer's lung (not to be confused with silo-filler's disease) is a hypersensitivity pneumonitis induced by the inhalation of biologic dusts coming from hay dust or mold spores or other agricultural products. It results in a type III hypersensitivity inflammatory response and can progress to become a chronic condition which is considered potentially dangerous. While inhaled allergens often provoke the creation of IgE antibodies that circulate in the bloodstream, these types of immune response are most often initiated by exposure to thermophilic actinomycetes (most commonly Saccharopolyspora rectivirgula), which generates IgG-type antibodies. Following a subsequent exposure, IgG antibodies combine with the inhaled allergen to form immune complexes in the walls of the alveoli in the lungs. This causes fluid, protein, and cells to accumulate in the alveolar wall which slows blood-gas interchange and compromises the function of the lung.

Epidemiology

Farmers lung is estimated to occur in up to 30 per 1000 farmers in general, and 42 in 100,000 dairy farmers.