Non-asthmatic eosinophilic bronchitis is characterized by persistent dry or less productive cough and bronchial eosinophilia without airway obstruction or bronchial hyperreactivity. It is primarily a chronic disease in which some patients have clinical and pathophysiological relapses while others progress to asthma or chronic obstructive pulmonary disease. It accounts for 5 to 30% of cases referred for chronic cough. Exposure to common inhalants and occupational sensitizers has been proposed as a possible cause of the disease, but its etiology and underlying mechanisms are uncertain. Some features were similar to those of asthma, such as airway eosinophilia, level of inflammatory mediators and airway remodeling.
Nevertheless, there are differences in airway pathophysiology, such as the location of airway inflammation and levels of IL-13 and PGE-2. Sputum cell count is the “gold standard” test for diagnosis, and other biomarkers, such as exhaled nitric oxide, could support the diagnosis. A systematic review of treatments for the disease has been done. Although inhaled corticosteroids are the primary treatment, the accurate dose, the kind of corticosteroid, and the treatment time remain unknown. Treatment duration is inversely correlated with relapse rate. Increased doses of inhaled corticosteroids, oral corticosteroids and leukotriene receptor antagonists are recommended in perseverance disease. Anti IL-5 biologic could be promising in this disease. There is a requirement for studies that investigate biomarkers for diagnosis and prognosis and randomized controlled studies for second-line treatments.

Key words: Eosinophilic bronchitis, Non-asthmatic eosinophilic bronchitis, Sputum, Chronic cough