Environmental challenge: An effective approach for diagnosis and remediation of exacerbations of hypersensitivity pneumonitis

To the Editor: An environmental avoidance challenge procedure, which may take several weeks for a response, is a critical tool in evaluating idiopathic interstitial lung disease to establish a diagnosis of hypersensitivity pneumonitis, identify a causative environment, and determine effective remediation. A "musty" smell, indicative of volatile organic compounds probably produced by molds, was noted throughout the residence by the patient and others; however, no mold growth was visualized.