Unspecified allergic alveolitis and pneumonitis

This code signifies an inflammatory condition of the alveoli and bronchioles in the lungs, triggered by an allergic reaction, where the specific allergen or type of alveolitis is not identified. It represents a general diagnosis of hypersensitivity pneumonitis without further specification of its cause.

This code is appropriate when a patient presents with symptoms and signs consistent with allergic alveolitis or pneumonitis, but diagnostic workup has not pinpointed the specific antigen or the physician has documented "allergic alveolitis, unspecified." It should be used when documentation lacks the detail to assign a more specific code from the 495 category.

• Avoid using this code if the specific type of allergic alveolitis (e.g., farmer's lung, bird fancier's lung) is documented.
• Review documentation for any mention of causative agents or specific forms of hypersensitivity pneumonitis before assigning this unspecified code.
• Consider if additional codes are needed to describe symptoms or complications associated with the condition.