Summary
Allergic bronchopulmonary aspergillosis (ABPA) results from hypersensitivity to the ubiquitary Aspergillus fumigatus fungus. It occurs in nearly 1% or 2% of asthmatic patients and in 10% of patients with cystic fibrosis, when chronic colonization by Aspergillus fumigatus of the airways results in complex interactions between Aspergillus, host relating factors allowing the colonisation, and immune responses of the host. The diagnosis is based on a set of major and/or minor criteria. ABPA is considered as certain when 7 major (or 6 major and 1 minor criteria) are present. Major criteria include: asthma, pulmonary infiltrates (typically recurring, corticosensitive or fixed), proximal bronchiectasis, blood eosinophilia (above 500 eosinophils/mm3), elevated serum Ig E (more than 2,000 international units), positive skin tests to Aspergillus fumigatus upon immediate reading, and the presence of precipitins (IgG) against Aspergillus antigens. Minor criteria include expectoration of mucous plugs containing Aspergillus fumigatus, and a positive skin test to Aspergillus fumigatus upon delayed reading. Recurrent mucous plugs are likely the cause of bronchiectasis which is well seen on the CT scan, appearing as large cystic or linear opacities predominating in the upper lobes of the lungs. ABPA is often diagnosed late and thus bronchiectasis is present in 85% of cases. ABPA becomes chronic with alternating phases of remission and exacerbation. Patients are treated with steroids during acute phases, and the doses are progressively decreased subsequently. An associated antifungal treatment with itraconazole is useful. Asthma may become corticodependent. Pulmonary lesions in advanced stages of the disease include proximal bronchiectasis, fibrosis and emphysematous destruction. * Authors: B. Etienne, M. D., Prof. JF Cordier (Apr. 2002) *
