Objective: Hypersensitivity pneumonitis (HP) comprises a large group of diseases that occur secondary to inhalation of a variety of antigens. This report describes a little-known cause of HP, previously unreported in the English literature.
Methods: Five patients (three women) with a mean age of 41 years who fulfilled the criteria for HP due to exposure to dry sausage dust were studied. The clinical findings, immunologic testing, results of the specific inhalation challenge, and follow-up are described.
Results: Three patients developed an acute form of disease and two patients a subacute form. A diffuse micronodular centrolobular pattern was seen on high-resolution computer tomography scanning of four patients. A restrictive pattern was identified on pulmonary function testing of four patients and decreased lung diffusion of carbon monoxide (DLCO) among three. In bronchoalveolar lavage specimens from three patients, lymphocytosis was 17%, 40%, and 40%, with a CD4/CD8 ratio of <0.6. Specific immunoglobin G (IgG) antibodies to Penicillium frequentans and Aspergillus fumigatus were positive for three patients. Performed on three patients, the specific inhalation challenge was positive for dry sausage dust extract in two cases and Penicillium frequentans in the third. Resolution of clinical, radiologic, spirometry, and DLCO alterations occurred among the three patients who avoided exposure following the diagnosis.
Conclusions: A short patient series affected by a little-known cause of occupational HP is described. Penicillium frequentans may be the causative agent in some cases, but other fungi were found that could also be implicated in the etiology of this disease.