Allergic bronchopulmonary aspergillosis

Abstract

Allergic bronchopulmonary aspergillosis (ABPA) is an immunological pulmonary disorder caused by hypersensitivity reactions mounted against Aspergillus fumigatus, which colonize the tracheobronchial tree of patients with asthma and cystic fibrosis. The most common presentation is with poorly controlled asthma. Other common manifestations include fever, hemoptysis, fleeting pulmonary opacities, and bronchiectasis. The disorder has a global presence and is especially prevalent in the Indian subcontinent. There are an estimated five million cases globally with 1.4 million cases in India alone. While the community prevalence of ABPA remains unclear, the prevalence of ABPA in clinics is about 13% and 9% in asthma and cystic fibrosis, respectively. The pathogenesis of ABPA is not completely understood, but there is a hyper-Th2 response in a genetically predisposed host. The most sensitive and specific investigations in the diagnosis of ABPA are A. fumigatus-specific IgE and identification of high-attenuation mucus on computed tomography, respectively. As the disease can remain surprisingly quiescent, all asthmatic patients should be screened for ABPA using A. fumigatus-specific IgE. The new criteria laid down by the ABPA working group of the International Society for Human and Animal Mycology are likely to help clinicians in making an accurate diagnosis. The treatment of ABPA includes the use of glucocorticoids to control the immune hyperreactivity and antifungal triazoles to attenuate the fungal burden in the airways. Early diagnosis and treatment can prevent the progression of bronchiectasis, a manifestation of irreversible airway damage.