The number of patients with allergic bronchopulmonary aspergillosis is estimated to be between 2500 and 5000 in Finland. Genetic factors and bronchial epithelial cells in those having asthma or cystic fibrosis may upon exposure to Aspergillus fungus lead to airway inflammation that can slowly damage the lung tissue. Treatment of the disease is primarily based on settling of the inflammation with an oral corticosteroid and currently often also with itraconazole medication directed to the inflammation and attempting to eradicate aspergillus. Long-term prognosis is quite good, provided that the disease is detected and treated at an early stage.