9-08: Allergic Bronchopulmonary Mycosis

Allergic bronchopulmonary mycosis is a pulmonary hypersensitivity disorder caused by allergy to fungal antigens that colonize the tracheobronchial tree. It usually occurs in atopic asthmatic individuals who are 20–40 years of age or those with cystic fibrosis, in response to antigens of Aspergillus species. For this reason, the disorder is commonly referred to as allergic bronchopulmonary aspergillosis (ABPA). Primary criteria for the diagnosis of ABPA include (1) a clinical history of asthma or cystic fibrosis; (2) elevated serum total IgE levels (typically greater than 1000 international units/mL; a value less than 1000 international units/mL may be acceptable if all other criteria are met); (3) immediate cutaneous hypersensitivity to Aspergillus antigens or elevated serum IgE levels specific to Aspergillus fumigatus; and (4) at least two of the following: (a) precipitating serum antibodies to Aspergillus antigen or elevated serum Aspergillus IgG by immunoassay, (b) radiographic pulmonary opacities consistent with ABPA, or (c) peripheral blood eosinophil count greater than 500 cells/mcL. Additional diagnostic features include identification of Aspergillus in sputum, a history of brown-flecked sputum, and late skin reactivity to Aspergillus antigen. High-dose prednisone (0.5–1 mg/kg orally per day) for at least 2 weeks is the initial treatment of choice. Depending on the clinical situation, prednisone dose can then be reduced or converted to every other day and slowly tapered over 3–6 months. Relapses are frequent, and protracted or repeated treatment with corticosteroids is not uncommon. Patients with corticosteroid-dependent disease may benefit from itraconazole (200 mg orally three times a day for 3 days, followed by twice daily [with food if the capsule formulation is used] for at least 16 weeks) without added toxicity. Bronchodilators (see Table 9–3) are also helpful. Complications include hemoptysis, severe bronchiectasis, and pulmonary fibrosis.