Synopsis
Recognise allergic bronchopulmonary aspergillosis as a treatable airway hypersensitivity syndrome, apply contemporary diagnostic criteria, distinguish activity from background structural lung disease, and monitor treatment without relying on a single laboratory value.
- ABPA is an exaggerated immune response to airway colonisation by Aspergillus, most often in asthma or cystic fibrosis; it is distinct from simple sensitisation and invasive aspergillosis.
- The revised ISHAM framework requires compatible disease or presentation, Aspergillus fumigatus sensitisation and raised total IgE, with additional immunological or imaging evidence rather than one positive test alone.
- Current diagnostic thresholds include A. fumigatus-specific IgE at least 0.35 kUA/L and total IgE usually at least 500 IU/mL, interpreted with steroid exposure, age and the clinical picture.
Key red flags
Expectoration of tenacious brownish plugs, segmental collapse or finger-in-glove impaction suggests obstructing allergic mucin. Extensive plugging with hypoxaemia requires urgent airway and imaging assessment.
Investigation priorities
Demonstrate fungal sensitisation as an essential diagnostic component.
Management branches
Uncontrolled asthma, unexplained mucus plugging or deterioration in cystic fibrosis or bronchiectasis raises suspicion of ABPA.
- Request A. fumigatus-specific IgE and total IgE, then add eosinophils, fungus-specific IgG and thin-section CT when sensitisation and clinical features make ABPA plausible.
- Apply current ISHAM criteria explicitly, recording whether each essential and supportive component is met and noting recent systemic steroid exposure that could suppress results.
Key medicines
Prednisolone for active ABPAUse a respiratory-specialist, time-limited regimen with a planned taper; the starting dose, duration and reduction schedule must reflect severity, comorbidity and the current local ABPA protocol.
Itraconazole as antifungal or steroid-sparing treatmentDose and formulation must follow the specialist ABPA protocol and product information, with therapeutic drug monitoring when indicated; capsules and oral solution have different administration and absorption requirements.