Diagnosis of Hypersensitivity Pneumonitis in Adults

Publication Date: August 1, 2020

Key Points

Key Points

  • Hypersensitivity pneumonitis (HP) must be considered in the differential diagnosis for patients with newly identified interstitial lung disease (ILD).
  • This guideline committee categorized HP into two clinical phenotypes—nonfibrotic and fibrotic HP—and made separate recommendations for each.

For patients with clinical and radiographic manifestations suggestive of nonfibrotic HP (i.e., patients without radiological and/or histopathological evidence of fibrosis), the guideline committee:
  • makes no recommendation or suggestion for or against the use of a questionnaire to identify potential HP inciting agents and sources. Instead, the guideline committee recommends development and validation of a questionnaire.Remark: Pending the availability of a validated questionnaire, the guideline committee advocates that clinicians take a thorough history to identify potential exposures and sources in the patient's environment that are known to be associated with HP.
suggests performing serum IgG testing that targets potential antigens associated with HP. (S, VL)
620
recommends obtaining bronchoalveolar lavage (BAL) fluid for lymphocyte cellular analysis. (C, VL)
620
suggests transbronchial forceps lung biopsy. (S, VL)
620
makes no recommendation or suggestion for or against transbronchial lung cryobiopsy.
suggests surgical lung biopsy only when all other diagnostic testing has not yielded a diagnosis. (S, VL)
620

For patients with clinical and radiographic manifestations suggestive of fibrotic HP (i.e., patients with radiological and/or histopathological evidence of fibrosis), the guideline committee:
  • makes no recommendation or suggestion for or against the use of a questionnaire to identify potential HP inciting agents and sources. Instead, the guideline committee recommends development and validation of a questionnaire.
    Remark: Pending the availability of a validated questionnaire, the guideline committee advocates that clinicians take a thorough history to identify potential exposures and sources in the patient’s environment that are known to be associated with HP.
suggests performing serum IgG testing that targets potential antigens associated with HP. (S, VL)
620
suggests performing serum IgG testing that targets potential antigens associated with HP. (S, VL)
620
makes no recommendation or suggestion for or against transbronchial forceps lung biopsy.
suggests transbronchial lung cryobiopsy. (S, VL)
620
suggests surgical lung biopsy; this recommendation is intended to apply when all other diagnostic testing has not yielded a diagnosis. (S, VL)
620

Diagnosis

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...r patients with newly identified ILD wh...


...h newly identified ILD whose differential...


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...1. Sources of Antigens Known to C...


...2. Recommended Chest HRCT Scannin...


.... Radiological Terms for Heterogenous Lung A...


...st HRCT Scan Features of the Nonfibrotic...


...Typical hypersensitivity pneumonitis (HP)” an...

...c typical HP pattern is characteriz...

...e 5. Chest HRCT Scan Features of the...

...Three-density Pattern

...n computed tomography (A) inspiratory and (B)...

...opathological Criteria for the Diagnos...

...Surgical Lung biopsy Specimen from a...

...ation photomicrograph showing preservation...

...(A–C) Poorly Formed Granulomas Charac...

...cation photomicrograph illustrating isolate...

...icrographs of Surgical Lung Biopsy Specimens...

...A) Scanning magnification view showing multipl...

...persensitivity Pneumonitis Diagnosis Base...

...Diagnostic Evaluation of Possible Hypersensitivity...