Hypersensitivity pneumonitis is known by many different names, most of which reflect the occupation or allergen most closely related to symptoms. Examples include:

• Farmer’s lung disease. From exposure to bacteria in moldy hay.
  
  
• Pigeon breeder’s disease. From exposure to protein particles in bird droppings.
  
  
• Mushroom worker’s disease. From exposure to moldy compost.
  
  
• Cheese worker’s lung. From cheese mold.
  
  
• Malt worker’s lung. From moldy malt.
  
  
• Paprika splitter’s lung. From paprika dust.
  
  
• Chemical worker’s lung. From the manufacture of plastics, polyurethane foam and rubber.
  
  
• Mollusk shell hypersensitivity. From shell dust.
  
  
• Sauna taker’s disease. From exposure to mold in wet containers.
  
  
• Bagassosis. From exposure to moldy sugar cane.

There are several conditions triggered by inhalation of organic agents that feature symptoms similar to those of hypersensitivity pneumonitis. They include:

• Inhalation fever. Symptoms include fever, chills, headaches and myalgias (muscle pain or tenderness). However, significant pulmonary impairment is not present.
  
  
• Organic dust toxic syndrome. Results from exposure to airborne particles contaminated with toxin-producing fungi (mycotoxins). Symptoms include fever, chills and myalgias. This differs from hypersensitivity pneumonitis in that sensitization does not need to occur prior to a reaction.
  
  
• Chronic bronchitis. Often the result of chronic obstructive pulmonary disease (COPD), the most common respiratory disorder among those who work in agriculture.