Merck Manual

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What Causes Hypersensitivity Pneumonitis?

What Causes Hypersensitivity Pneumonitis?


Source of Dust Particles or Antigens



Bird fancier's lung, pigeon breeder's lung, hen worker's lung

Dusts consisting of droppings from parakeets, pigeons, and chickens

Cheese washer's lung

Cheese mold

Chemical worker's lung

Chemicals used in manufacturing polyurethane foam, molding, insulation, synthetic rubber, and packaging materials

Coffee worker's lung

Unroasted coffee beans

Cork worker's lung (suberosis)

Moldy cork

Farmer's lung

Moldy hay

Hot tub lung

Bacteria-contaminated hot tubs and therapy pools

Humidifier lung

Humidifiers and air conditioners

Maple bark stripper's lung

Infected maple bark

Malt worker's lung

Moldy barley or malt

Miller's lung

Weevil-infested wheat flour

Mushroom worker's lung

Mushroom compost


Moldy sawdust from redwoods

Woodworker's lung

Wood dust