What is Allergic Bronchopulmonary Aspergillosis (ABPA) and its management?

From the Guidelines

Allergic Bronchopulmonary Aspergillosis (ABPA) is a hypersensitivity reaction to Aspergillus fungi that primarily affects people with asthma or cystic fibrosis, and its management involves a two-pronged approach: controlling inflammation and reducing fungal burden, with oral corticosteroids and antifungal medications like itraconazole being the cornerstone of therapy.

Definition and Diagnosis

ABPA is characterized by a hypersensitivity reaction to Aspergillus fungi, leading to inflammation and damage in the lungs. The diagnosis of ABPA involves demonstrating fungal sensitization, serum total IgE ≥500 IU·mL−1, and two of the following: fungal-specific IgG, peripheral blood eosinophilia, or suggestive imaging 1.

Management

The management of ABPA involves controlling inflammation and reducing fungal burden.

• Oral corticosteroids, typically prednisolone, are recommended as the initial therapy for acute ABPA, with a dose of 0.5 mg/kg/day for 2 weeks, followed by gradual tapering over 2-3 months 1.
• Itraconazole is recommended as a steroid-sparing agent for patients dependent on oral corticosteroids, with a dose of 200 mg twice daily for 16-24 weeks 1.
• Voriconazole may be considered as an alternative antifungal medication, although its use as first-line therapy is limited due to concerns about patient tolerance and interactions with prednisolone 1.
• Biological agents, such as omalizumab, may be considered for steroid-dependent patients, although there is limited evidence to support their use as first-line therapy 1.

Monitoring and Follow-up

Regular monitoring of patients with ABPA includes pulmonary function tests, chest imaging, and serum IgE levels every 6-8 weeks during treatment 1.

• Patients with chronic Pseudomonas aeruginosa, non-tuberculous mycobacteria (NTM), or methicillin-resistant Staphylococcus aureus (MRSA) colonization, deteriorating bronchiectasis, or recurrent exacerbations should be followed up in secondary care 1.
• Environmental modifications to reduce Aspergillus exposure, such as avoiding compost, construction sites, and using HEPA filters, are also important in the management of ABPA [@Example@].

Quality of Life and Morbidity

The goal of ABPA treatment is to prevent permanent lung damage from repeated inflammatory episodes, which can lead to bronchiectasis and fibrosis if inadequately managed.

• Optimizing management of underlying conditions, such as asthma or cystic fibrosis, is crucial in improving quality of life and reducing morbidity.
• Regular monitoring and follow-up are essential in preventing exacerbations and reducing the risk of long-term complications.

Overall, the management of ABPA requires a comprehensive approach that involves controlling inflammation, reducing fungal burden, and optimizing management of underlying conditions, with the goal of improving quality of life and reducing morbidity.

From the Research

Definition and Characteristics of ABPA

• Allergic bronchopulmonary aspergillosis (ABPA) is a complex hypersensitivity reaction to airway colonization by Aspergillus fumigatus in patients with asthma and cystic fibrosis 2, 3.
• ABPA is characterized by an immunologic reaction to the antigens of noninvasive Aspergillus fumigatus, which colonizes the bronchial lumen of affected individuals 2.
• The disorder usually complicates the course of patients with asthma and cystic fibrosis, presenting with chronic cough, wheezing, and dyspnea due to uncontrolled asthma 3, 4.

Diagnosis of ABPA

• Criteria for diagnosis of ABPA include episodic bronchial obstruction, peripheral blood eosinophilia, immediate cutaneous reactivity to A. fumigatus, precipitating serum antibodies to A. fumigatus, elevated total serum IgE, history of pulmonary infiltrates, elevated serum IgE and serum IgG to A. fumigatus, and proximal bronchiectasis 2.
• The definitive diagnosis of ABPA requires a combination of clinical, radiological, and immunological findings 3.
• New diagnosis and staging criteria for ABPA have been proposed by the International Society for Human and Animal Mycology (ISHAM) working group on ABPA complicating asthma 5.

Management and Treatment of ABPA

• The management of ABPA aims to reduce symptoms, prevent disease progression, and minimize the future risk of exacerbations 3.
• The treatment approach involves systemic glucocorticoids or antifungal agents to suppress the inflammatory response or fungal growth and prevent exacerbations 3, 4.
• Oral prednisone is the most effective treatment for ABPA, with a recommended dose of 0.5 mg/kg/day for 14 days, on alternate days for three months, and tapering by 5 mg every two weeks for an additional three months 2.
• Itraconazole can be used as a steroid-sparing agent, and optimized asthma therapy is also essential for primary therapy 5, 6.
• Biological agents may be used in patients with severe disease or glucocorticoid dependence 3.
• The proposed treatment scheme for CF-related ABPA, including oral prednisone for 18 days together with itraconazole therapy for at least 12 months, is effective in preserving lung function capacity over years in affected individuals without the known glucocorticoid-associated side effects 6.