Prognostic indicators in extrinsic allergic alveolitis

Background: Extrinsic allergic alveolitis belongs among the most often diagnosed interstitial lung diseases. However, little data concerning the impact of antigen-type, presentation of disease and treatment, on the patient ś prognosis, is available. Methods: Thirty eight patients were enrolled in a retrospective study. Data collected between January 2007 and December 2010 were analyzed. Patients were divided, at the time of diagnosis, into subacute and chronic extrinsic allergic alveolitis (EAA) groups according to their clinical presentation. One year after diagnosis, baseline lung function tests and treatment data were evaluated. Using high resolution computed tomography (HRCT), interstitial and alveolar changes were characterized with the help of a scoring system. Results: We found no effects linked to the nature of the inhaled antigen or the treatment modality on lung functions 12 months after EAA diagnosis. Patients with subacute EAA had significantly better lung function tests after one year than patients with chronic EAA. Patients with chronic EAA had significantly higher HRCT interstitial scores than the subacute group (1.1 ± 1.2 vs. 2.9 ± 0.9). Correlations between HRCT interstitial scores and changes in lung functions were observed. Conclusions: Only the clinical pattern of EAA and HRCT interstitial scores correlated with lung functions at the one year follow up.