Allergic extrinsic alveolitis

This is a hypersensitivity reaction within the lungs to an inhaled organic dust. The best example of this condition is Farmer's lung, caused by spores of thermophilic actinomycetes. Other examples of this condition include:

• an allergic extrinsic alveolitis in grain handlers, due to dust derived from the grain weevil Sitophilus granarius
  
  
• bird fancier's lung results from the allergic response to avian antigens e.g. dust from feathers and faeces
  
  
• mushroom worker's lung is an allergic response to thermophilic actinomycetes spores in mould
  
  
• maltworker's lung - Aspergillus clavatus spores