Summary
Definition
History and exam
Key diagnostic factors
- exposure to avian protein antigen, especially excrement
- mould in work environment
- occupational exposure to chemicals
- dyspnoea
- cough
Other diagnostic factors
- fever/chills
- malaise
- weight loss/anorexia
- bibasilar rales
- diffuse rales
- clubbing
Risk factors
- smoking
- viral infection
- exposure to avian protein antigen
- exposure to mould antigen
- exposure to bacterial antigen
- exposure to diisocyanate (e.g., epoxy resin)
- exposure to acid anhydride antigen (e.g., paint refinisher)
- exposure to metalworking fluid
- use of certain drugs
- use of e-cigarettes
- ayurvedic medicine
Diagnostic investigations
1st investigations to order
- chest x-ray
- high-resolution CT chest
- serum antigen-specific IgG or IgA
- pulmonary function tests
- diffusing lung capacity of carbon monoxide
Treatment algorithm
Contributors
Authors
Leslie Grammer, MD
Professor
Northwestern University Feinberg School of Medicine
Director
Ernest S. Bazley Asthma and Allergy Center
Clinic Practice Director
Allergy-Immunology
Northwestern Medical Faculty Foundation
Chicago
IL
Disclosures
LG declares that she has no competing interests.
Peer reviewers
Maximiliano Tamae-Kakazu, MD, FCCP
Associate Professor of Medicine
Program Director, Pulmonary and Critical Care Medicine Fellowship
Research Director, Pulmonary and Critical Care Medicine
Corewell Health West - Michigan State University College of Human Medicine
East Lansing
MI
Disclosures
MTK received fees from InflaRx as a consultant to participate in a COVID-19 pneumonia Advisory Board. MTK received fees from Pfizer as a consultant to participate in a healthcare disparities in primary immunodeficiencies advisory board. MTK received fees from Regeneron as consultant on the pathophysiology of asthma and need of education in fellowship programs advisory board in January 2022. All the honoraria have been donated to the Corewell Health Foundation.
Toby M. Maher, MB, MSc, PhD, MRCP
Consultant Respiratory Physician
Interstitial Lung Disease Unit
Royal Brompton Hospital
London
UK
Disclosures
TMM has received consultancy fees from GSK, Actelion, and Philips Respironics. He has received lecture fees from Astra Zeneca and holds an unrestricted industry-academic grant from GSK.
Peer reviewer acknowledgements
BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.
Disclosures
Peer reviewer affiliations and disclosures pertain to the time of the review.
References
Key articles
Raghu G, Remy-Jardin M, Ryerson CJ, et al. Diagnosis of hypersensitivity pneumonitis in adults. An Official ATS/JRS/ALAT clinical practice guideline. Am J Respir Crit Care Med. 2020 Aug 1;202(3):e36-69.Full text Abstract
Quirce S, Vandenplas O, Campo P, et al. Occupational hypersensitivity pneumonitis: an EAACI position paper. Allergy. 2016 Jun;71(6):765-79.Full text Abstract
Fernández Pérez ER, Travis WD, Lynch DA, et al. Diagnosis and evaluation of hypersensitivity pneumonitis: CHEST guideline and expert panel report. Chest. 2021 Aug;160(2):e97-156.Full text Abstract
Reference articles
A full list of sources referenced in this topic is available here.
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