Hypersensitivity Pneumonitis

Patient Guideline Summary

Publication Date: April 13, 2021

Last Updated: March 3, 2023

Objective

This patient summary means to discuss key recommendations from the American College of Chest Physicians for hypersensitivity pneumonitis.

Overview

Hypersensitivity pneumonitis is an allergic reaction to airborne irritants.

Some of the most common causes are bacteria, molds, animals, and industrial chemicals.

Symptoms include breathing difficulty and coughing.

This patient summary focuses on the diagnosis of hypersensitivity pneumonitis.

Diagnosis

The top priority is identifying the irritating agents by an intensive review of exposures related to symptoms.
- For workplace symptoms, an occupational medicine specialist will be helpful.
- For other locations an environmental hygienist is useful.
Imaging studies – high-resolution computed tomography (HRCT) – will be needed to determine if the lungs are fibrotic.
HRCT and symptom response to medical treatment will aid in the diagnosis.
Bronchoscopy, lung biopsy, and laboratory testing may be needed as well.
A complete diagnosis depends not only on the above findings but also on individual patient experience with irritant control and a discussion among the treatment team.

Abbreviations

HRCT: High-resolution Computed Tomography

Source Citation

Fernández Pérez ER, Travis WD, Lynch DA, Brown KK, Johannson KA, Selman M, Ryu JH, Wells AU, Tony Huang YC, Pereira CAC, Scholand MB, Villar A, Inase N, Evans RB, Mette SA, Frazer-Green L. Diagnosis and Evaluation of Hypersensitivity Pneumonitis: CHEST Guideline and Expert Panel Report. Chest. 2021 Aug;160(2):e97-e156. doi: 10.1016/j.chest.2021.03.066. Epub 2021 Apr 20. PMID: 33861992.

Disclaimer

The information in this patient summary should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.