Intermittent itraconazole therapy for preventing asthma exacerbations

INTERVENTION: 50 mg/day (low dose) itraconazole for 7 days in every month for 12 months 500 mg/day carbocysteine for 7 days in every month for 12 months CONDITION: Bronchial asthma PRIMARY OUTCOME: 1.Comparison of frequency of asthma attack during next one year between 2 groups.; 2.Comparison of frequency of asthma attack between last year and this year.; 3.Statistical analysis of two groups against the results of skin reaction tests of Schizophyllum commune. SECONDARY OUTCOME: 1.Comparison of allergological changes and clinical courses. INCLUSION CRITERIA: Age 20‐70 years old