Home environmental fungal exposure in patients with Hypersensitivity Pneumonitis – pilot analysis

Abstract

Introduction: Identification and exposure avoidance of the causal antigen are essential for hypersensitivity pneumonitis (HP) diagnosis and management. We hypothesized that mold exposure could explain the relatively high prevalence of this disease in our region.

Aims: To evaluate the mycological exposure in the home environment of patients with HP.

Methods: A thorough home environment evaluation of patients with a recent HP diagnosis was performed by a trained public health researcher, including collection of air samples using a single-stage microbiologic air impactor with malt extract agar plates. Upon incubation, fungal colony quantification and microscopic identification were performed. Data was expressed in total and specific colony forming units per cubic meter (CFU/m3).

Results: Seventeen patients were recruited, with a median age 65 years (min-max, 31-80), 9 (52.9%) were male. Most patients (82.3%, n=14) had fibrotic HP.

A total of 11 houses had signs of infiltrations, mold, or wall discoloration, however 45.5% (n=5) failed to report it to the doctor at the first hospital visit.

The air sample was collected in the bedroom of all patients (n=17).

Seventeen different fungal species were identified with Cladosporium and Penicillium spp as the most prevalent.

A total of 12 patients (70.6%) had either toxic levels of specific fungus or indoor superior to outdoor CFU/m3. From these, the mean indoor fungal concentration was 715 CFU/m3 and outdoor was 421 CFU/m3.

Conclusions: We found a high prevalence of elevated fungal concentration in HP patient’s household. Identification of potential antigens within the exposure environment is crucial to understand the immunological response.