Allergic Bronchopulmonary Mycosis due to fungi other than Aspergillus

Abstract

Allergic bronchopulmonary mycosis (ABPM) is a clinical syndrome associated with immune sensitivity to various fungi that colonize the airways. Early diagnosis and treatment with systemic corticosteroids is the key in preventing the progression of the disease to irreversible lung fibrosis. Although Aspergillus has progressively gained recognition as a causative agent in past few decades, other fungi, that have been reported to cause ABPM, are not yet widely evaluated. We studied hundred and two patients with asthma for occurrence of ABPM. Patients were tested for cutaneous hypersensitivity and serum precipitin to 12 common fungal antigens. The positive cases were further evaluated for ABPM using standard criteria. Out of 102 asthma patients screened, 18 patients had either skin prick test (SPT) and/or serum precipitin positive. While 14 patients were SPT positive for one or more fungal antigen, two patients were serum precipitin positive for one or more fungi. Two patients had both serum precipitin positive as well as SPT positive. Six (5.8%) patients were diagnosed as ABPM as they fulfilled the criteria. Three of these were because of Aspergillus sp. Two were because of fungi other than Aspergillus namely Schizophyllum and Curvularia. One patient had ABPM because of both Aspergillus and Curvularia. In our study absolute eosinophil count (AEC), total IgE, serum precipitin and SPT had sensitivity of 100%, 100% 50% and 83.3% respectively for diagnosing ABPM. The specificity of these tests was 44.79%, 64.58% 98.96% and 88.54% respectively. Specfic IgE was positive in 50% of patients with either serum precipitin or SPT positivity. SPT or serum precipitin followed by specific IgE had sensitivity of 100% and specificity of 96.88% for diagnosing ABPM. SPT alone followed by Specific IgE had a sensitivity of 83.33% and specificity of 96.88% for diagnosing ABPM. We found that fungi other than Aspergillus such as schizophyllum, and curvularia, can be implicated in ABPM. Multiple fungal agents may be responsible for ABPM in an individual. There is a subset of patients of BA who have fungal sensitization but do not fulfil the criteria for ABPM. SPT was the single most sensitive and specific test, AEC >350 and total IgE more than 417IU were most sensitive tests and SPT followed by specific IgE was most effective strategy for diagnosing ABPM.