B44.81 Allergic bronchopulmonary aspergillosis

Name of the Condition

• Allergic bronchopulmonary aspergillosis

Summary

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity reaction to Aspergillus species, most commonly Aspergillus fumigatus, in the airways. It primarily affects individuals with underlying asthma or cystic fibrosis, leading to bronchial inflammation, mucus plugging, and potential lung damage. The condition is characterized by recurrent exacerbations and may progress to bronchiectasis if untreated.

Causes

ABPA is caused by an allergic response to inhaled Aspergillus spores. In susceptible hosts, the fungus colonizes the bronchial mucosa, triggering a type I and III hypersensitivity reaction. This results in eosinophilic inflammation, bronchial wall damage, and excessive mucus production. The immune response to fungal antigens drives the clinical manifestations, rather than direct tissue invasion.

Risk Factors

• Pre-existing asthma or cystic fibrosis.
• Chronic lung diseases with bronchial inflammation.
• Environmental exposure to high Aspergillus spore concentrations.
• Genetic predisposition to allergic responses.
• Prior respiratory infections or bronchial damage.

Symptoms

• Recurrent wheezing, cough, and shortness of breath.
• Expectoration of brownish mucus plugs or sputum.
• Low-grade fever or malaise during exacerbations.
• Chest tightness or localized pain.
• Progressive dyspnea in advanced cases.

Diagnosis

Diagnosis involves a combination of clinical, radiological, and laboratory findings. Key criteria include asthma or cystic fibrosis, elevated total serum IgE, positive Aspergillus skin test or specific IgE, and radiographic evidence of transient pulmonary infiltrates or bronchiectasis. Sputum cultures may show Aspergillus colonization, and pulmonary function tests often reveal obstructive patterns. Imaging may demonstrate central bronchiectasis or mucoid impaction.

Treatment Options

Treatment focuses on reducing inflammation and managing allergic responses. Corticosteroids (e.g., prednisone) are first-line for acute exacerbations, often followed by long-term azole antifungals (e.g., itraconazole) to suppress fungal growth. Inhaled corticosteroids and bronchodilators help control underlying asthma. Regular monitoring of IgE levels and lung function guides therapy adjustments.

Prognosis and Follow-Up

With appropriate treatment, most patients achieve symptom control and prevent progression. However, relapses are common, requiring ongoing management. Long-term follow-up includes periodic IgE monitoring, lung function testing, and imaging to detect bronchiectasis or fibrosis. Adherence to therapy and avoidance of triggers improve outcomes.

Complications

• Bronchiectasis and irreversible lung damage.
• Recurrent respiratory infections.
• Asthma exacerbations or loss of lung function.
• Systemic steroid side effects with prolonged use.
• Rare progression to chronic pulmonary aspergillosis.

Lifestyle & Prevention

• Minimize exposure to moldy environments or construction sites.
• Use air purifiers with HEPA filters in high-risk areas.
• Maintain optimal asthma or cystic fibrosis management.
• Avoid smoking and secondhand smoke.
• Follow vaccination schedules to prevent respiratory infections.

When to Seek Professional Help

Seek care if experiencing worsening wheezing, persistent cough, fever, or increased sputum production. Prompt evaluation is critical for acute exacerbations or signs of respiratory decline. Emergency care is needed for severe dyspnea, hemoptysis, or signs of respiratory failure.

Tips for Medical Coders

Document the underlying condition (e.g., asthma, cystic fibrosis) and confirm ABPA diagnosis via clinical criteria (e.g., elevated IgE, radiographic findings). Ensure specificity of Aspergillus involvement and exclude invasive disease. Code B44.81 is appropriate for allergic bronchopulmonary aspergillosis; verify no concurrent invasive infection to avoid miscoding.