Table of contents
Allergic bronchopulmonary aspergillosis
Background
Overview
Definition
ABPA is a hypersensitivity reaction to the opportunistic mold Aspergillus, most commonly Aspergillus fumigatus.
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Pathophysiology
The pathophysiology of ABPA involves a dominant Th2 immune response to antigens derived from Aspergillus fumigatus. The disease is characterized by marked local and systemic eosinophilia, an adaptive immune response with elevated levels of Aspergillus fumigatus-specific IgG, IgA, and IgE antibodies, and a profound nonspecific IL-4-dependent elevation in total IgE.
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Epidemiology
The prevalence of ABPA is estimated at around 2.5% in adult patients with asthma. The incidence of ABPA in Spain is estimated at 126 per 100,000 person-years.
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Risk factors
The main risk factors for developing ABPA are having asthma or cystic fibrosis. Less common risk factors include other lung diseases associated with immunocompromise, such as tuberculosis, chronic granulomatous disease, and hyper-IgE syndrome.
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Disease course
Clinically, ABPA manifests with recurring episodes of asthma, pulmonary infiltrates, and central bronchiectasis. It may progress to fibrosis if not properly managed.
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Prognosis and risk of recurrence
The prognosis of ABPA is largely dependent on the severity of the disease and the patient's response to treatment. While some patients may experience a complete resolution of symptoms with appropriate treatment, others may have recurrent exacerbations or progress to more severe forms of the disease.
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Guidelines
Key sources
The following summarized guidelines for the evaluation and management of allergic bronchopulmonary aspergillosis are prepared by our editorial team based on guidelines from the Infectious Diseases Society of America (IDSA 2016) and the American Thoracic Society (ATS 2011).
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Diagnostic investigations
Medical management
Antifungal therapy
As per IDSA 2016 guidelines:
Consider initiating oral itraconazole with therapeutic drug monitoring in symptomatic patients with asthma and bronchiectasis or mucoid impaction despite oral or ICS therapy.
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Consider initiating oral itraconazole in patients with cystic fibrosis experiencing frequent exacerbations and/or falling FEV1 to minimize corticosteroid use with therapeutic drug monitoring. Consider initiating other mold-active azole therapies if therapeutic levels cannot be achieved.
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More topics in this section
Corticosteroids
Bronchodilators
Leukotriene antagonists
Follow-up and surveillance
Laboratory and imaging monitoring: as per ATS 2011 guidelines, obtain regular monitoring of serum IgE levels, serial monitoring of pulmonary function tests, and chest imaging in all patients with ABPA. Adjust the corticosteroid dosing when imaging evidence, such as infiltrates, mucoid impaction, fibrosis, or worsening bronchiectasis, is present.
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