Coexisting atopic conditions influence the likelihood of allergic bronchopulmonary aspergillosis in asthma

Background: The diagnosis of allergic bronchopulmonary aspergillosis (ABPA) in asthma is often made in patients with total serum IgE levels greater than 1,000 IU/mL in conjunction with evidence of Aspergillus sensitization. The specificity of total serum IgE for the diagnosis of ABPA is low even when combined with serum Aspergillus specific IgE. Objective: To determine the prevalence of ABPA and to identify alternative clinical predictors for ABPA among asthmatic patients with a total serum IgE level greater than 1,000 IU/ml. Methods: This study was conducted in a tertiary hospital in Melbourne, Australia, with a large asthma and allergy service. Patients with asthma and total serum IgE levels greater than 1,000 IU/ml from January 1, 2005, through December 31, 2014, were included. Patients were considered to have concomitant allergic conditions if they had atopic eczema, allergic rhinitis, or both. The diagnosis of ABPA was based on the managing physician's documented diagnosis and referenced to criteria proposed by the International Society for Human and Fungal Mycology. Results: The prevalence of ABPA in our cohort was 15.8%. Older age, elevated total serum IgE level, reduced lung function, and the absence of other concomitant allergic conditions increased the risk of ABPA. After multivariate logistic regression, patients without concomitant allergic conditions had an odds ratio of 4.4 (95% confidence interval, 1.9-10.1; P = .001) for ABPA when compared with patients with allergic conditions. Conclusion: The absence of atopic eczema and allergic rhinitis in these patients increases the likelihood of ABPA. Eliciting an accurate allergy history may be a useful bedside clinical tool when considering the diagnosis of ABPA.