Urine Leukotriene E4 Levels in Children with Nonspecific Isolated Chronic Dry Cough

Chronic cough is the most common complaint during childhood. Various pathophysiologic mechanisms may cause cough. Knowledge of the mechanisms underlying chronic cough plays an important role in the choice of treatment to evaluate the role of leukotrienes in children with nonspecific isolated chronic dry cough. The patient group consisted of children with isolated chronic dry cough persisting for >4 weeks and the control group included healthy children. Medical histories were elicited and physical examinations were performed, then respiratory function testing was done and chest X-rays were obtained. Patients were given inhaled corticosteroid. The urine leukotriene E4 (uLTE4) levels in the patient and control groups was measured by enzyme immunoassay. The patient group included 55 patients, 25 of them were males between 6 and 12 years old. The control group included 25 healthy children between 6 and 12 years old, 12 of them were males. There were no pathologic findings on physical examinations, pulmonary function testing, and chest X-rays. The complaints of cough in 50 patients were resolved after treatment. The median level of uLTE4 was 73.1 ng/mmol creatinine (range, 15.59-787.55 ng/mmol creatinine) in the patient group, and 64.2 ng/mmol creatinine (range, 12-282 ng/mmol creatinine) in the control group. No significant difference was detected between the 2 groups with respect to age, gender, and uLTE4 levels. Different pathophysiologic mechanisms are known to influence nonspecific isolated chronic dry cough. Various mechanisms, other than leukotrienes, may also give rise to dry cough.