Pediatric Hypersensitivity Pneumonitis: Clinicopathologic Characteristics of Two Cases with Fungal Triggers.

Background: Hypersensitivity pneumonitis (HP) infrequently presents in childhood. Asthma or a pneumonia-like clinical presentation may lead to diagnostic delay, especially in children. Case Report: We present two cases of HP, a 6-year-old (Case 1) male and a 5-year-old (Case 2) female. Both cases had a negative infectious work-up and patchy ground glass lung opacities on chest computed tomography. Lung biopsies demonstrated lymphocytic bronchiolitis with granulomatous interstitial and peribronchial inflammation. Serology demonstrated elevated immunoglobulin precipitins toward Thermoactinomyces and Aspergillus species in Case 1 and Aspergillus fumigatus in Case 2. Both patients received steroid therapy and had symptom resolution. Conclusions: A diagnosis of HP should be considered in pediatric lung biopsies with granulomatous interstitial and peribronchial inflammation, if infectious etiologies are excluded. Integration of clinical, radiological, and laboratory findings can facilitate a timely diagnosis.