Sweat test in asthmatic children; a single center study.

Asthma and Cystic Fibrosis (CF) have some identical manifestations. In the present study, the frequency of positive sweat test was assessed in asthmatic children. This cross-sectional study was performed in asthmatic children, who were referred to Bahrami Children Hospital, Tehran, during July 2003 to July 2005. Sweat test was performed for all children. One hundred and thirty five (95 males and 40 females) asthmatic were studied. Sweat test was positive in 35 (26%) patients. Major signs and symptoms among these 35 patients were: Cough (35/35), Dyspnea (7/35), Chronic Diarrhea (6/35), and steatorrhea (1/35). Failure to thrive was found in 31 of 35 patients. The mean duration of asthma in patients with positive test was 49.3 months, which was significantly higher than 18.1 months in the group with negative test (P=0.001). Significant relations between recurrent respiratory tract infections (P=0.029), chronic diarrhea (P=0.001), failure to thrive (P=0.0001), and positive sweat test were found. Sweat test should be recommended in asthmatic children with recurrent upper respiratory tract infections, long duration of asthma, chronic diarrhea, and failure to thrive.