How should I approach the management of a patient with cystic fibrosis who develops symptoms suggestive of ABPA?

For a patient with cystic fibrosis who develops symptoms suggestive of allergic bronchopulmonary aspergillosis (ABPA), first assess for elevated aspergillus serology, including aspergillus-specific IgG and/or IgE, and evaluate for declining pulmonary function despite optimised pulmonary treatment. If these findings are present along with consistent chest X-ray or CT scan changes, consider treating for ABPA or other aspergillus airway disease. This approach helps target the underlying allergic and infectious components contributing to the patient's symptoms. Oral corticosteroids are typically considered for treatment in this context, especially if there is continued deterioration in lung function or repeated pulmonary exacerbations despite other treatments. In addition, antifungal therapy may be considered to suppress Aspergillus infection if there is chronic Aspergillus fumigatus complex respiratory infection with declining pulmonary status, but specialist microbiological advice should be sought regarding the choice and duration of antifungal agents. Avoid inhaled corticosteroids as immunomodulatory treatment for cystic fibrosis as they are not recommended. Continue to monitor pulmonary function and adjust treatment based on clinical response and microbiological findings.