Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity lung disease driven by an exaggerated Th2 immune response to Aspergillus fumigatus colonizing the airways of patients with asthma or cystic fibrosis. Systematic review estimates show ABPA in approximately 2.5% of adults with asthma and 7-9% of patients with cystic fibrosis, with a global burden of roughly 4-5 million cases.
Allergic bronchopulmonary aspergillosis (ICD-10: B44.81) is a hypersensitivity lung disease caused by an exuberant Th2 immune response to Aspergillus fumigatus that colonizes the airways without invading tissue. The condition develops in genetically and immunologically susceptible patients, predominantly those with poorly controlled atopic asthma or cystic fibrosis. Inhaled Aspergillus conidia germinate in the bronchial mucus of these patients; chronic antigen presentation drives IL-4, IL-5, and IL-13 production, with B-cell IgE class switching, eosinophilic airway inflammation, mucus impaction, central bronchiectasis, and eventually fibrosis. ISHAM 2024 consensus criteria require asthma or cystic fibrosis, Aspergillus-specific IgE above 0.35 kUA/L (or positive skin prick test), and total IgE above 500 IU/mL (often >1,000 IU/mL), together with at least two of: positive Aspergillus IgG/precipitins, blood eosinophils above 500 cells/µL, and chest imaging compatible with ABPA (transient infiltrates, mucus plugging, or central bronchiectasis).
key facts
Prevalence
Approximately 2.5% of adults with asthma; 7-9% of patients with cystic fibrosis (Agarwal et al. 2009 systematic review)
Demographics
Adults aged 20-50 most commonly affected; equal sex distribution; higher prevalence in South Asia, the Middle East, and parts of Europe
Avg. age
Mean age of diagnosis 30-45 years; mean asthma duration before ABPA recognition 5-15 years
Global cases
Estimated 4-5 million people worldwide; high under-diagnosis in low- and middle-income settings
Specialist
Allergy & Immunology
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How you might notice it
The key symptoms of Allergic Bronchopulmonary Aspergillosis are: Worsening asthma symptoms (wheeze, breathlessness, cough) that fail to respond to standard inhaled corticosteroid plus long-acting beta-agonist therapy., Expectoration of thick, sticky brownish or olive-green mucus plugs, sometimes cast-like, that occasionally bring up Aspergillus hyphae on microscopy., Recurrent low-grade fever, malaise, anorexia, and weight loss during exacerbations., Haemoptysis from bronchiectatic airways or mucus impaction., Chest tightness and pleuritic chest pain during pulmonary infiltrates., Chronic productive cough with copious sputum in patients with established bronchiectasis., Progressive exertional breathlessness and reduced exercise tolerance in advanced disease..
01Worsening asthma symptoms (wheeze, breathlessness, cough) that fail to respond to standard inhaled corticosteroid plus long-acting beta-agonist therapy.
02Expectoration of thick, sticky brownish or olive-green mucus plugs, sometimes cast-like, that occasionally bring up Aspergillus hyphae on microscopy.
03Recurrent low-grade fever, malaise, anorexia, and weight loss during exacerbations.
04Haemoptysis from bronchiectatic airways or mucus impaction.
05Chest tightness and pleuritic chest pain during pulmonary infiltrates.
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How it’s diagnosed
diagnosis
Diagnosis combines clinical, immunological, and imaging criteria. The 2024 ISHAM/WHO consensus criteria require asthma or cystic fibrosis as the predisposing condition, plus elevated Aspergillus fumigatus-specific IgE (>0.35 kUA/L) or positive immediate-type skin prick test, and total serum IgE above 500 IU/mL (often >1,000 IU/mL); plus at least two of three: positive Aspergillus precipitins or specific IgG, blood eosinophil count above 500 cells/µL (without recent oral corticosteroid), and chest imaging compatible with ABPA (transient infiltrates, mucus plugging, central bronchiectasis). Initial work-up includes total serum IgE, A. fumigatus-specific IgE (preferred over skin prick test for quantification), Aspergillus precipitins or specific IgG, full blood count with eosinophils, sputum culture (often grows Aspergillus species), high-resolution CT of the chest, spirometry, and asthma control assessment. Distinctive HRCT findings include central bronchiectasis with sparing of distal airways, mucus impaction (the finger-in-glove sign), high-attenuation mucus on non-contrast CT (a hallmark feature), tree-in-bud opacities, and peripheral consolidation that resolves between episodes. Total IgE is the single best biomarker for monitoring; serial measurements track response and detect relapse. Differential diagnosis includes severe asthma without ABPA, eosinophilic granulomatosis with polyangiitis (Churg-Strauss), chronic eosinophilic pneumonia, hypersensitivity pneumonitis, sarcoidosis, tuberculosis, and bronchiectasis from other causes. Patterson staging is used at diagnosis and follow-up to guide therapy intensity.
Key tests
01
Total serum IgECentral diagnostic and monitoring biomarker; levels typically >500 IU/mL and often >1,000 IU/mL
✓Oral prednisolone 0.5-0.75 mg/kg/day, tapered over 3-6 months
✓Itraconazole 200 mg twice daily for 16 weeks
✓Voriconazole 200 mg twice daily (or weight-based) for 16 weeks
✓Inhaled corticosteroid plus long-acting beta-agonist (asthma control)
surgical options
Bronchoscopic mucus plug removalRe-expansion of collapsed lung in 80-90% of cases; symptomatic improvement is usually rapid
Bronchial artery embolizationInitial control of haemoptysis in 80-90%; rebleeding rate 10-30% within 1-2 years
Lung transplantation5-year survival 50-60% in published series; long-term outcomes complicated by chronic rejection
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Causes & risk factors
known causes
Hypersensitivity to Aspergillus fumigatus
ABPA is driven by a Th2-skewed immune response to A. fumigatus antigens. Inhaled conidia colonize mucus in the airways of susceptible patients; persistent antigen presentation drives IL-4, IL-5, IL-13, and high-affinity IgE production with eosinophilic inflammation and tissue remodelling.
Underlying asthma
Asthma is the most common host condition, present in 80-90% of ABPA cases. Atopic asthma with elevated total IgE provides the immunological substrate; chronic airway inflammation and mucus retention support fungal colonization.
Cystic fibrosis
Approximately 7-9% of patients with cystic fibrosis develop ABPA, supported by viscous airway mucus and chronic bacterial-fungal interactions. Diagnostic criteria are modified to account for baseline lung disease.
Genetic susceptibility
HLA-DR2 and HLA-DR5 alleles confer susceptibility. Polymorphisms in surfactant protein A, IL-4, IL-10, and the chloride channel CFTR (heterozygous status) raise risk. Polymorphisms in mannose-binding lectin and toll-like receptors influence severity.
Environmental Aspergillus exposure
Higher exposure to fungal spores through dampness, compost, agricultural work, or warm humid climates increases the antigenic load and probably the risk of developing ABPA. Indoor mould remediation and humidity control help reduce exposure.
risk factors
Atopic asthmanon-modifiable
Patients with severe or poorly controlled asthma have approximately 2.5% prevalence of ABPA; uncontrolled asthma raises the risk. Atopy with raised IgE is a strong predisposing background.
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Living with it
01Achieve and maintain good asthma or cystic fibrosis control with adherent inhaled therapy to reduce mucus retention and fungal colonization.
03Use HEPA air filtration in the bedroom for sensitized patients.
04Avoid occupational mould exposure (compost, hay, agricultural settings) when possible; use respiratory protection if unavoidable.
05Stop smoking and avoid second-hand smoke to protect lung function.
06Screen asthma patients with poor control and CF patients annually with total IgE and Aspergillus-specific IgE.
07Vaccinate annually against influenza and complete pneumococcal vaccination schedule.
recommended foods
•Mediterranean-style diet rich in fruit, vegetables, oily fish, olive oil, and whole grains
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When to seek help
why see an allergy & immunology
A pulmonologist or allergist with ABPA experience is needed to confirm the diagnosis, design corticosteroid and antifungal regimens, manage drug interactions and toxicity, and decide on biologic therapy. Multidisciplinary input from cystic fibrosis teams, ENT for sinusitis, and interventional radiology for haemoptysis is essential.
ABPA-S (seropositive, without bronchiectasis)Early disease with positive immunological criteria but normal high-resolution CT of the chest. Best prognosis; corticosteroids and antifungal therapy usually achieve remission without structural damage.
ABPA-CB (with central bronchiectasis)Characteristic central bronchiectasis predominantly affecting the upper lobes with sparing of the periphery. Established structural disease that may progress despite treatment.
ABPA-CB-HAM (with high-attenuation mucus)Variant with hyperdense mucus plugs on non-contrast CT (more attenuating than chest-wall muscle). Associated with severe disease, higher relapse rates, and worse outcomes.
ABPA in cystic fibrosisAffects approximately 7-9% of patients with cystic fibrosis. Distinct diagnostic considerations (modified criteria) because of baseline lung disease, abnormal CT, and chronic colonization.
Patterson staging (acute, remission, exacerbation, steroid-dependent, fibrotic)Clinical stages from initial diagnosis (acute) through remission (after 6 months off steroids), exacerbation (relapse), steroid-dependent asthma, and end-stage fibrotic disease.
Living with Allergic Bronchopulmonary Aspergillosis
Timeline
Symptoms typically improve within 1-2 weeks of starting oral steroids. Eosinophils normalize within 1-2 weeks. Total IgE falls 25-50% over 6-8 weeks of treatment. Imaging infiltrates resolve over 1-3 months. Many patients require 3-6 months of tapering steroid therapy. Bronchiectasis, once established, is permanent but progression can be slowed.
Lifestyle
01Take asthma controller therapy daily and use a written action plan with peak flow monitoring.
02Avoid known mould exposure (basements, compost piles, mouldy hay) and wear an N95 respirator when unavoidable.
03Maintain a balanced diet rich in fresh fruit, vegetables, oily fish, and whole grains.
04Exercise regularly with moderate aerobic activity and pulmonary rehabilitation when bronchiectasis is established.
05Stop smoking permanently and avoid second-hand smoke.
06Perform daily airway clearance (Acapella, active cycle of breathing) for patients with bronchiectasis.
07Limit alcohol while on antifungal therapy because of liver interactions.
Daily management
01Take oral steroids in the morning with food, maintaining the tapering schedule.
Complementary approaches
Mould exposure reduction (home remediation, dehumidifiers, HEPA filtration)Reducing fungal antigen load in damp homes lowers airway exposure. Address basements, leaks, and indoor humidity above 50%.
Pulmonary rehabilitationStructured exercise, breathing technique, and education programme for patients with established bronchiectasis or chronic disease. Improves exercise capacity and quality of life.
Choosing a doctor
Choose a centre with severe asthma or bronchiectasis specialist clinic, high-resolution CT capability, therapeutic drug monitoring for antifungals, and access to biologic therapies. Ask about exacerbation rates, biologic experience, and policies on prolonged steroid use.
Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity lung disease caused by an allergic reaction to Aspergillus fumigatus colonizing the airways of patients with asthma or cystic fibrosis. Symptoms include worsening asthma, mucus plug expectoration, fever, and migratory pulmonary infiltrates.
Who gets ABPA?▾▴
ABPA affects approximately 2.5% of adults with asthma and 7-9% of patients with cystic fibrosis. Risk is highest in atopic patients with poorly controlled asthma, those with severe asthma, and patients with environmental exposure to Aspergillus spores.
What are the symptoms of ABPA?▾▴
Symptoms include worsening asthma despite inhaled steroids, expectoration of brownish mucus plugs, low-grade fever, haemoptysis, productive cough, and recurrent migratory pulmonary infiltrates on chest imaging. Many patients have years of difficult-to-control asthma before diagnosis.
How is ABPA diagnosed?▾▴
Diagnosis combines asthma or cystic fibrosis as a host condition, elevated Aspergillus-specific IgE, total serum IgE above 500 IU/mL, plus at least two of positive Aspergillus precipitins, eosinophilia above 500 cells/µL, and CT findings of central bronchiectasis or mucus impaction.
What does ABPA look like on CT?▾▴
Characteristic CT findings include central bronchiectasis with peripheral sparing, mucus impaction (the finger-in-glove sign), high-attenuation mucus plugs, tree-in-bud opacities, and migratory peripheral consolidation. High-attenuation mucus is highly specific for ABPA.
How is ABPA treated?▾▴
First-line treatment is oral prednisolone 0.5-0.75 mg/kg/day for 2-4 weeks tapered over 3-6 months, with itraconazole 200 mg twice daily for 16 weeks as steroid-sparing antifungal therapy. Biologics targeting IgE, IL-5, or IL-4/IL-13 are used in steroid-dependent disease.
Can ABPA be cured?▾▴
ABPA is a chronic relapsing condition rather than a curable infection. Most patients achieve remission with treatment, but 30-50% relapse within 5 years. Long-term outcomes depend on early diagnosis, adherence, and lifestyle changes including mould exposure reduction.
Is ABPA contagious?▾▴
No. ABPA is an allergic response to inhaled Aspergillus spores and is not transmitted from person to person. Aspergillus spores are common in the environment, but only susceptible individuals (with asthma or cystic fibrosis) develop the disease.
What is total IgE in ABPA?▾▴
Total serum IgE is markedly elevated in ABPA, typically above 500 IU/mL and often above 1,000 IU/mL. It is the single best biomarker for diagnosis and monitoring; a 25-50% fall during treatment indicates remission and a 50% rise from baseline often signals relapse.
Are antifungals enough on their own?▾▴
Antifungals alone are usually insufficient as first-line therapy; oral corticosteroids are the cornerstone for controlling eosinophilic inflammation. Itraconazole or voriconazole is added to reduce exacerbations and lower the steroid dose, especially in patients with frequent relapse.
Can biologics treat ABPA?▾▴
Yes. Omalizumab (anti-IgE), mepolizumab and benralizumab (anti-IL-5), and dupilumab (anti-IL-4Rα) are increasingly used in steroid-dependent ABPA. Observational evidence shows reduced exacerbations, steroid sparing, and improved lung function. Randomized trials are ongoing.
Does ABPA cause permanent lung damage?▾▴
Long-standing or recurrent ABPA can cause permanent bronchiectasis and, in advanced cases, pulmonary fibrosis. Early diagnosis and adequate treatment slow or prevent structural progression. Patients with high-attenuation mucus or established bronchiectasis at diagnosis have worse long-term outcomes.
What is the life expectancy in ABPA?▾▴
Most patients with treated ABPA have near-normal life expectancy. Those with end-stage fibrosis, respiratory failure, or major haemoptysis have higher mortality. Coexisting cystic fibrosis is the main determinant of overall survival in CF patients with ABPA.
How long do you take steroids for ABPA?▾▴
A typical course is 3-6 months of prednisolone with progressive tapering. Patients with relapse or steroid dependence may need longer or alternative agents (itraconazole, biologics) to limit cumulative steroid toxicity.
Can I prevent ABPA?▾▴
Risk reduction includes optimal asthma or cystic fibrosis control, indoor humidity below 50%, mould remediation in damp homes, HEPA filtration, avoidance of compost and mouldy hay, and respiratory protection in occupational exposure. Annual screening with total IgE in severe asthma helps early diagnosis.
Does ABPA affect children?▾▴
Yes. ABPA can present in adolescents and young adults, especially those with cystic fibrosis. Symptoms include difficult-to-treat asthma, mucus plug expectoration, and recurrent infiltrates. Diagnostic criteria and treatment are similar to adults.
What is the difference between ABPA and aspergilloma?▾▴
ABPA is an allergic disease driven by hypersensitivity to Aspergillus in the airways of asthma or CF patients. Aspergilloma is a fungal ball that grows in pre-existing lung cavities (e.g., post-TB), causing haemoptysis. Both involve Aspergillus but are pathologically and clinically distinct.
Can I exercise with ABPA?▾▴
Yes. Regular moderate exercise (walking, swimming, cycling) is encouraged. Pulmonary rehabilitation is beneficial for patients with established bronchiectasis. Avoid mouldy environments and untreated freshwater. Pace activity during exacerbations and resume gradually after recovery.
Does diet affect ABPA?▾▴
A Mediterranean-style diet supports overall health; calcium, vitamin D, and protein are important during long-term steroid therapy. Avoid grapefruit juice on itraconazole or voriconazole. Limit alcohol because of antifungal hepatotoxicity risk.
How often should ABPA be monitored?▾▴
Patients are followed every 6-12 weeks during active treatment with total IgE, lung function, and symptom review. Once in remission, monitoring extends to 3-6 monthly. Total IgE rising more than 50% above baseline often signals relapse.
Should family members be tested?▾▴
Routine screening of family members is not recommended unless they have asthma, cystic fibrosis, or recurrent unexplained respiratory disease. Genetic predisposition is modest; environmental exposure is a major contributor.
Chronic productive cough with copious sputum in patients with established bronchiectasis.
07Progressive exertional breathlessness and reduced exercise tolerance in advanced disease.
08New or worsening fatigue not explained by asthma alone, often paralleling rising eosinophil and IgE counts.
09Recurrent migratory pulmonary infiltrates on chest X-ray that may shift between lobes between presentations.
10Symptoms despite high-dose inhaled corticosteroids and biologic therapy targeting asthma, prompting investigation for ABPA.
early warning signs
•Asthma that is increasingly difficult to control despite step-up therapy
•Recurrent chest X-ray infiltrates in an asthmatic patient
•Peripheral blood eosinophilia above 500 cells/µL in an asthma or cystic fibrosis patient
•Sputum production with visible mucus plugs of brownish or rusty colour
•Rising total serum IgE in a patient with known asthma without recent atopy change
•Decline in lung function (FEV1) without other identifiable cause
● emergency signs
•Massive haemoptysis (>200 mL in 24 hours) from bronchiectatic vessels — emergency interventional radiology and bronchial artery embolization
•Acute severe asthma with poor response to standard therapy, hypoxia, and hypercapnia
•Pneumothorax with sudden chest pain and breathlessness
•Lobar collapse from mucus impaction with hypoxia and respiratory distress
•Allergic broncho-aspergillosis evolving into invasive aspergillosis in severely immunocompromised patients (rare but life-threatening)
Aspergillus precipitins or specific IgGDetects sensitization to Aspergillus through IgG response
04
Full blood count with eosinophilsDocuments eosinophilia (>500 cells/µL is criterion); high counts during exacerbation
05
High-resolution CT of the chestIdentifies central bronchiectasis, mucus impaction (finger-in-glove sign), high-attenuation mucus, and infiltrates
06
Sputum culture and microscopyIdentifies Aspergillus hyphae and excludes bacterial or mycobacterial infection
07
Spirometry and lung volumesQuantifies airflow obstruction and tracks lung function decline
08
Aspergillus skin prick testDemonstrates immediate-type hypersensitivity; positive in nearly all ABPA cases
Outlook
With early diagnosis and treatment, 70-80% of patients achieve clinical remission and many remain stable for years. However, relapse rates are 30-50% within 5 years, and 20-30% of patients become steroid-dependent. Long-term outcomes depend on the stage at diagnosis: ABPA-S has the best prognosis with often complete resolution; ABPA-CB shows fixed bronchiectasis but stable lung function with treatment; ABPA-CB-HAM and fibrotic ABPA have higher exacerbation rates and progressive lung function decline. Lung function (FEV1) declines on average 1-2% per year in well-treated ABPA but faster in those with frequent exacerbations. Mortality is uncommon but rises in patients with established fibrosis, respiratory failure, or complications such as massive haemoptysis. Biologic therapy is changing the long-term outlook for steroid-dependent disease, with case series showing sustained remission and substantial corticosteroid sparing. Total IgE remains the best biomarker for monitoring; a sustained rise (>50% above remission baseline) is the earliest sign of relapse.
Cystic fibrosisnon-modifiable
7-9% of CF patients develop ABPA, with viscous mucus, chronic airway colonization, and baseline atopy contributing.
HLA-DR2 and HLA-DR5 alleles, CFTR heterozygous status, and Th2-skewing polymorphisms confer susceptibility. Family clustering occurs occasionally.
Environmental Aspergillus exposureenvironmental
Damp housing, basements, compost piles, agricultural work, mouldy hay, and warm humid climates increase Aspergillus inhalation and disease risk.
Geographic location (South Asia, Middle East, parts of Europe)environmental
Prevalence is notably higher in India and the Middle East, partly because of climate, indoor air quality, and possibly population-level atopy patterns.
Severe asthma with frequent exacerbationsmodifiable
Patients hospitalized with severe asthma exacerbations have a higher prevalence of ABPA; aggressive asthma management and screening for ABPA are warranted.
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Adequate calcium (1,000 mg/day) and vitamin D (800-1,000 IU/day) for bone protection on long-term steroids
•Protein-rich diet (1.0-1.2 g/kg/day) to support immune function and prevent steroid myopathy
•Moderate intake of probiotic-rich foods (yoghurt, kefir) to support gut health on antifungals
foods to avoid
•Mouldy or visibly fermented foods that can increase airborne Aspergillus exposure
•Grapefruit juice while on itraconazole or voriconazole (significant CYP3A4 interaction)
•Heavy alcohol consumption while on antifungals (hepatotoxicity risk)
•Excess added sugars and saturated fats that worsen steroid-induced metabolic side effects
07Itraconazole toxicity (hepatotoxicity, drug interactions, heart failure) — monitor liver function and drug levels.
choosing the right hospital
01Severe asthma or interstitial lung disease specialist clinic
02High-resolution CT and respiratory radiology expertise
03Therapeutic drug monitoring for itraconazole and voriconazole
04Pulmonary function laboratory with bronchoprovocation capability
05Access to bronchial artery embolization and bronchoscopy
Essential facilities
Tertiary pulmonology centresAdult and paediatric cystic fibrosis clinicsSevere asthma specialist servicesAllergy and immunology departmentsInterventional radiology for haemoptysis
02Take itraconazole capsules with a meal or acidic drink to enhance absorption (oral solution preferred when taken on empty stomach).
03Use inhaled controller therapy every morning and evening, and a reliever as needed.
04Monitor peak expiratory flow daily and record values in a chart.
05Watch for warning signs of exacerbation (increased breathlessness, sputum colour change, fever) and contact specialist promptly.
06Maintain hydration to keep airway mucus thin and aid expectoration.
07Avoid known fungal exposures and use respiratory protection in dusty or mouldy environments.
Exercise
Encourage 150 minutes of moderate aerobic activity weekly. Pulmonary rehabilitation is recommended for patients with established bronchiectasis or fibrosis. Avoid swimming in untreated freshwater because of fungal contamination risk. Resume activity gradually after exacerbations.