Farmer's lung

This code represents an extrinsic allergic alveolitis, specifically hypersensitivity pneumonitis, caused by inhalation of thermophilic actinomycetes found in moldy hay or other agricultural products. It is an immune-mediated inflammatory lung disease resulting from repeated exposure to specific organic dusts.

Use this code when documentation clearly indicates a diagnosis of Farmer's lung, often presenting with symptoms like dyspnea, cough, fever, and chills following exposure to moldy organic materials. This diagnosis is typically supported by a history of agricultural exposure, clinical symptoms, imaging findings (e.g., ground-glass opacities, centrilobular nodules), and sometimes serologic tests for specific antibodies.

• Ensure documentation specifies "Farmer's lung" or clearly describes hypersensitivity pneumonitis due to moldy hay/agricultural dust.
• Differentiate from other forms of extrinsic allergic alveolitis; if the specific allergen is unknown or different, a more general code for hypersensitivity pneumonitis may be appropriate.
• Consider sequencing with codes for acute or chronic respiratory failure if present and treated.