Chronic Cough Due to Chronic Interstitial Pulmonary Diseases: Treatment

The pathogenesis of cough in HP is unknown. Pathologically, the small airways are affected by cellular granulomatous inflammatory change (a bronchiolitis), and physiologic airflow limitation, either with or without reversibility, is frequently iden-tified. This suggests that in at least a portion of patients, the mechanism may be similar to that of asthma. In the chronic or fibrotic form of the disease, airflow limitation is much less common; however, cough is at least as frequent, suggesting that additional mechanisms are also operative.
The diagnosis of HP requires a comprehensive evaluation, as noted above. Often strongly suggestive historical evidence of exposure will be present. The appropriate history combined with typical radiographic, physiologic, and serologic precipitin features with a lymphocytic BAL sample and/or trans-bronchial lung biopsy findings of bronchiolocentric granulomatous inflammation are often adequate for diagnosis. However, in order to attribute the cough solely or primarily to HP requires that cough go away with successful treatment for HP.

Therapy for patients with HP requires the elimination of the causative exposure with or without the use of corticosteroids. While therapy with corticosteroids is regularly recommended for acute disease, symptomatically and physiologically severe disease, and progressive disease, their long-term efficacy has yet to be proven. In patients with acute farmer’s lung, pulmonary function and symptoms improve with 2 months of therapy with corticosteroids; however, this approach may not alter the long-term outcome. The use of inhaled corticosteroids is theoretically useful; however, few data are available to support this approach.
In patients with cough, ILD, and a concerning environmental, occupational, or avoca-tional exposure, HP should be considered as a potential cause. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
In patients with cough due to HP, treatment should include the removal of the offending exposure and systemic corticosteroid therapy in those with evidence of physiologic impairment. Level of evidence, low; benefit, substantial; grade of recommendation, B

This entry was posted in Pulmonary Function and tagged hypersensitivity pneumonitis, idiopathic pulmonary fibrosis, interstitial lung disease, sarcoidosis.