Chapter 7 Allergic bronchopulmonary aspergillosis and other fungal diseases

Fungal spores are ubiquitously present in the air. Inhalation of these spores by humans causes disease in susceptible patients; most prevalent are invasive aspergillosis and allergic bronchopulmonary aspergillosis (ABPA). This chapter provides an overview of the pathogenecity, clinical appearance, diagnosis and treatment of ABPA. ABPA is a hypersensitivity lung disease limited to patients with asthma or cystic fibrosis (CF) with a prevalence of 1–2% and 2–15%, respectively within these groups. It is triggered by the exposure to Aspergillus fumigatus. Although it is not clear what initiates this hypersensitivity response, polymorphisms in genes that drive innate and adaptive immune mechanisms as well as loss-of-function mutations in the CF transmembrane conductance regulator (CFTR) are associated with ABPA development. The chronic inflammatory conditions in ABPA eventually result in airway remodelling and functional impairment. The diagnosis of ABPA is based both on clinical symptoms, laboratory testing and diagnostic imaging. Treatment consists of a two tiered approach, glucocorticoids to control immunological activity and antifungal agents to suppress fungal load.