Nonasthmatic Eosinophilic Bronchitis: An Overlooked Cause of Chronic Cough in Children

Non-asthmatic eosinophilic bronchitis (NAEB) is an inflammatory airway disease that causes chronic cough, responds well to inhaled steroids, and can be misdiagnosed as asthma because of the pathophysiologic overlap. Unlike asthma, NAEB is not associated with airway hyperresponsiveness. NAEB has not been previously described in children. We report a case of a child with chronic cough, eosinophilic airway inflammation, and a negative methacholine challenge test, strongly suggestive of a diagnosis of NAEB. The patient was a 10-year-old boy who was hospitalized with a 2-year history of chronic productive cough and exertional dyspnea, which did not respond to repeated treatment with oral antibiotics or inhaled bronchodilators. On examination, he appeared tachypneic with low O2 saturation (89%) on room air. Chest auscultation revealed bilateral crackles. WBC, ESR, and CRP were elevated. Peripheral eosinophil count and Immunoglobulin E (IgE) level were normal. Pulmonary function testing (PFT) demonstrated a combined obstructive and restrictive pattern with air trapping. Fractional exhaled nitric oxide (FeNO) was normal. Chest CT showed airway wall thickening and bilateral small centrilobular nodules, with no evidence of bronchiectasis or interstitial lung infiltrates. Flexible bronchoscopy revealed diffuse thick airway secretions. Bronchoalveolar lavage (BAL) fluid analysis showed a high eosinophil count of 40%. BAL cultures were negative. The patient was initially treated with IV antibiotics and airway clearance. He was then started on inhaled steroids using budesonide/salmeterol MDI (160/25 mcg) because of the airway eosinophilia. Within a few days of treatment with inhaled steroids, the patient's symptoms improved significantly. He was weaned off O2. The inflammatory markers normalized. Chest CT showed resolution of the abnormal infiltrates. Repeat PFT 4 months later was normal. Methacholine challenge testing was performed twice after discontinuing inhaled steroids, and both tests showed no airway hyperresponsiveness. NAEB is a possible cause of chronic cough in children that can mimic asthma. Bronchoscopy and a methacholine challenge test may be needed for diagnosis.