Updates in Hypersensitivity Pneumonitis: A Narrative Review

Abstract

Purpose of Review Hypersensitivity pneumonitis (HP) is an immune-mediated disease triggered by a known or unknown antigen. While reversible in the early stages of disease, progression toward irreversible pulmonary fibrosis may occur. This narrative review summarizes recent publications highlighting a methodical approach toward the diagnosis, classification, and management of fibrotic and nonfibrotic HP. Recent Findings Establishing the diagnosis of HP is often challenging given its variable clinical course, extensive inciting agents, and overlapping features with other interstitial lung diseases. Recently, HP has been re-classified into nonfibrotic and fibrotic subtypes based on radiographic and histopathological features. Chronic fibrotic HP is associated with significant functional impairment and increased mortality. In addition to antigen avoidance, immunosuppression is the cornerstone of management in nonfibrotic HP. Antifibrotic agents have emerged as a therapeutic option in halting the progression of chronic fibrotic HP. Summary The combination of clinical, radiographical, and histopathological data will assist in increasing the diagnostic certainty of HP. The new dichotomization of HP is thought to provide better prognostication for patients. This review provides clinicians with a current and evidence-based approach toward the management of patients with HP.

Prevalence of hypersensitive pneumonitis specific IgG antibodies in the Indian population: A retrospective study

“…In the United States, HP accounts for less than 2% of ILD cases, with an annual occurrence of approximately 30 cases per 100,000 individuals. 3 Notably, data from the interstitial lung disease-India registry indicates a substantial prevalence of 47.3% for HP within the spectrum of interstitial lung diseases. 4 Historically, HP classification comprised acute, subacute, or chronic forms.…”