How to Diagnose Allergic Bronchopulmonary Aspergillosis

Abstract

An immunologically mediated lung disease, allergic bronchopulmonary aspergillosis (ABPA) is predominantly found in patients with asthma and cystic fibrosis (CF). This indolent entity is diagnosed by a set of well established criteria that have unfolded over time. Other than demonstration of central bronchiectasis (CB) with normal tapering bronchi, which is regarded as a key component for the diagnosis of ABPA in patients without CF, we still do not have a single test that could clinch the diagnosis. Of late, ABPA has also been observed in patients without asthma. The Cystic Fibrosis Foundation ABPA Consensus Conference, in 2001, proposed diagnostic as well as screening criteria for ABPA in CF. Radiologic findings have always been crucial to the diagnosis and monitoring of ABPA. Although not pathognomonic, “transient pulmonary infiltrates”, also known as “fleeting shadows”, are characteristically seen, and often provide the first clue in Aspergillus sensitised asthmatics. Identification of CB on computed tomography is recognised as a hallmark and, when present, the patient is labelled as ABPA-CB. Those fulfilling all the serologic diagnostic criteria except presence of CB are categorised as ABPA-S. During the last decade or so, recombinant Aspergillus fumigatus allergens have been developed for skin testing and serodiagnosis, especially in those with CF. In essence, this potentially destructive lung disease must be sought for in asthma and CF patients with a positive skin prick test to Aspergillus antigens.