What is the workup for Allergic Bronchopulmonary Aspergillosis (ABPA)?

From the Guidelines

The workup for Allergic Bronchopulmonary Aspergillosis (ABPA) should begin with A. fumigatus-specific IgE levels, followed by serum total IgE measurement if the result is ≥0.35 kUA·L−1, and then other tests such as A. fumigatus-specific IgG, peripheral blood eosinophil count, chest CT, and lung function tests to characterize the disease 1. The diagnostic algorithm for ABPA involves several steps, including measuring A. fumigatus-specific IgE levels and serum total IgE, which should be ≥500 IU·mL−1 to suspect ABPA 1. Some key points to consider in the workup include:

• Measuring A. fumigatus-specific IgE levels as the initial step
• Obtaining serum total IgE levels if A. fumigatus-specific IgE is ≥0.35 kUA·L−1
• Performing other tests such as A. fumigatus-specific IgG, peripheral blood eosinophil count, chest CT, and lung function tests to characterize the disease
• Considering the presence of high-attenuation mucus (HAM) on chest CT as pathognomonic for ABPA, even if some other criteria are missing 1
• Using a comprehensive approach to diagnose ABPA, as no single test is diagnostic, and early diagnosis is crucial to prevent irreversible lung damage from chronic inflammation 1. It is essential to follow a step-by-step approach to diagnose ABPA, as outlined in the revised ISHAM-ABPA working group clinical practice guidelines 1.

From the Research

ABPA Workup

• The workup for Allergic Bronchopulmonary Aspergillosis (ABPA) involves considering the disease in patients with asthma or cystic fibrosis, and a positive skin test result for Aspergillus, and/or recurrent infiltrates on radiographs 2.
• Diagnostic criteria for ABPA are regularly revised and are mainly based on the elevation of total and specific IgE against Aspergillus fumigatus and the presence of suggestive CT abnormalities such as mucoid impaction and consolidations 3.
• The differential diagnosis for ABPA in patients with asthma includes diseases such as chronic eosinophilic pneumonia, Churg-Strauss syndrome, drug-induced pulmonary infiltrates, infection with a parasite, asthma with atelectasis, and lymphoma 2.

Diagnosis and Treatment

• Early diagnosis of ABPA allows treatment at an initial stage, preventing recurrence of exacerbations and long-term complications, mainly represented by bronchiectasis 3.
• Treatment of ABPA includes eviction of mold and pharmacological therapy, with exacerbations treated in first line with a moderate dose of oral corticosteroids 3.
• Azole antifungal agents represent an alternative for the treatment of exacerbations and are the preferential strategy to reduce the future risk of exacerbations and for corticosteroids sparing 3.
• Asthma biologics, such as omalizumab, may be of interest in treating ABPA, particularly in cases resistant to treatment with antiasthmatic drugs and antifungal agents 4.

Management and Complications

• The management of ABPA aims to avoid complications while limiting the side effects of systemic drugs, which remains a major challenge 3.
• Bronchiectasis is an irreversible complication of ABPA, and preventing it is a key goal of treatment 2, 5.
• Several drugs, including new antifungals and asthma biologics, are currently being tested and may be useful in the future management of ABPA 3.