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Allergic Bronchopulmonary Aspergillosis (ABPA)

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Allergic Bronchopulmonary Aspergillosis (ABPA)

Allergic bronchopulmonary aspergillosis (ABPA) is an allergic hypersensitivity reaction to Aspergillus fumigatus colonizing the airways, occurring mainly in patients with asthma or cystic fibrosis.

Also called

Allergic pulmonary aspergillosis (less commonly used)

ICD-10

B44.81

Specialty

Pulmonology

Onset

Chronic

Reviewed

July 2026

On This Page

Overview

  • ABPA results from an exaggerated immune response to Aspergillus fumigatus, leading to:

    • Airway inflammation
    • Mucus plugging
    • Recurrent pulmonary infiltrates
    • Bronchiectasis

    Untreated disease may cause progressive lung damage and permanent bronchiectasis.

Etiology & Risk Factors

-Cause

An exaggerated immune hypersensitivity reaction to Aspergillus fumigatus colonizing the airways.

-Risk Factors

  • Asthma (most common)

  • Cystic fibrosis

  • Atopy

  • Elevated IgE levels

  • Recurrent exposure to Aspergillus spores

Important Note

ABPA is an allergic reaction to Aspergillus—not an invasive fungal infection.

Pathophysiology

Airway colonization by Aspergillus fumigatus
⬇
Type I and Type III hypersensitivity reactions
⬇
IgE production + Eosinophilic inflammation
⬇
Airway edema + Mucus plugging
⬇
Recurrent airway inflammation
⬇
Central bronchiectasis
⬇
Progressive lung damage if untreated

-Key Concept

Repeated allergic inflammation causes irreversible bronchiectasis if untreated.

Clinical Presentation

Symptoms

  • Wheezing

  • Cough

  • Dyspnea

  • Thick brown mucus plugs

  • Fever (occasionally)

  • Chest tightness

  • Recurrent asthma exacerbations

  • Hemoptysis

Signs

    • Wheezing

    • Crackles

    • Reduced air entry during exacerbations

History Taking

    • Ask about:

      • History of asthma?
      • Cystic fibrosis?
      • Frequent asthma exacerbations?
      • Wheezing?
      • Dyspnea?
      • Productive cough?
      • Brown mucus plugs?
      • Hemoptysis?
      • Previous pulmonary infiltrates?

Physical Examination

-General Examination

Look for:

  • Wheezing
  • Tachypnea
  • Respiratory distress
  • Reduced oxygen saturation (severe disease)

-Chest Examination

May show:

  • Wheezing
  • Crackles
  • Reduced air entry

Important Note

Physical examination findings are often similar to an asthma exacerbation.

Investigations of Allergic Bronchopulmonary Aspergillosis (ABPA)

-Blood Tests

  • Total serum IgE (markedly elevated)
  • Peripheral eosinophil count
  • Aspergillus-specific IgE
  • Aspergillus-specific IgG

-Skin Testing

  • Immediate hypersensitivity skin test to Aspergillus

-Chest Imaging

Chest X-ray

May show:

  • Transient pulmonary infiltrates
  • Mucus plugging

-High-Resolution CT (HRCT)

May show:

  • Central bronchiectasis
  • Mucus plugging
  • Finger-in-glove opacities

-Pulmonary Function Tests

Usually show:

    • Obstructive pattern

Diagnosis of Allergic Bronchopulmonary Aspergillosis (ABPA)

-Diagnosis is based on:

1. Predisposing Condition

  • Asthma
  • Cystic fibrosis

2. Immunologic Evidence

  • Elevated total IgE
  • Positive Aspergillus-specific IgE or skin test

3. Supportive Findings

    • Peripheral eosinophilia
    • Central bronchiectasis
    • Pulmonary infiltrates
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Related Topics

Management of Allergic Bronchopulmonary Aspergillosis (ABPA)

-Main Goals

  • Control allergic inflammation

  • Prevent lung damage

  • Reduce exacerbations

  • Preserve lung function

Corticosteroids

Oral corticosteroids are the main treatment.

Antifungal Therapy

May include:

  • Itraconazole

  • Voriconazole (selected patients)

Used to reduce the fungal burden and decrease antigen exposure.

-Asthma Management

  • Inhaled corticosteroids

  • Bronchodilators

  • Standard asthma treatment

-Biologic Therapy

May be considered in selected refractory patients.

Complications of Allergic Bronchopulmonary Aspergillosis (ABPA)

  • Central bronchiectasis
  • Pulmonary fibrosis
  • Chronic respiratory failure
  • Recurrent exacerbations
  • Permanent lung damage
  • Reduced lung function

Prognosis of Allergic Bronchopulmonary Aspergillosis (ABPA)

  • Early diagnosis and treatment usually lead to good outcomes.
  • Recurrent untreated disease may result in irreversible bronchiectasis and fibrosis.
  • Prognosis depends on:
    • Disease severity
    • Frequency of exacerbations
    • Treatment adherence
    • Presence of established bronchiectasis

Key Points / Clinical Pearls of Allergic Bronchopulmonary Aspergillosis (ABPA)

  • ABPA is an allergic reaction to Aspergillus fumigatus, not an invasive fungal infection.
  • It occurs mainly in patients with asthma or cystic fibrosis.
  • Poorly controlled asthma with eosinophilia should raise suspicion of ABPA.
  • Markedly elevated total IgE is a key laboratory finding.
  • Central bronchiectasis is the classic HRCT finding.
  • Systemic corticosteroids are the main treatment.
  • Antifungal therapy may reduce fungal burden in selected patients.
  • Early treatment helps prevent irreversible lung damage.
  • National Center for Biotechnology Information (NIH). Allergic Bronchopulmonary Aspergillosis, StatPearls.
  • Agarwal R, Sehgal IS, Muthu V, et al; ISHAM-ABPA Working Group. Revised ISHAM-ABPA Working Group Clinical Practice Guidelines for Diagnosing, Classifying and Treating Allergic Bronchopulmonary Aspergillosis/Mycoses. Eur Respir J. 2024;63:2400061. doi: 10.1183/13993003.00061-2024.
  • Patterson K, Strek ME. Allergic Bronchopulmonary Aspergillosis. Proc Am Thorac Soc. 2010. PMID: 20463254.
  • Shah A, Panjabi C. Allergic Bronchopulmonary Aspergillosis: A Perplexing Clinical Entity. Allergy Asthma Immunol Res. 2016. PMC4809788.
  • MedlinePlus, National Library of Medicine (NIH). Aspergillosis: Medical Encyclopedia.