Does tuberculosis protect against allergy in children? A controlled study of 108 cases

ABSTRACT

The "hygiene hypothesis" suggests that early childhood infections might prevent atopic diseases later. The aim of this study is to evaluate asthma and rhino-conjunctivitis prevalence in children with confirmed tuberculosis in the early childhood. All children with confirmed tuberculosis between 1992 and 1997 were recruited from Casablanca Saada Tuberculosis Diagnosis Center register. The families completed questionnaire about anamnestic and clinical manifestations of asthma and rhino-conjunctivitis. All children with clinical evidence of atopy had skin prick-tests. A control group age-matched, sex-matched and geographically matched had the same questionnaire and the same explorations. 54 children, from 6 to 17 year-old, were enrolled and completed the questionnaire. 24 children [44%] had a familial history of atopy. Passive smoking was found in 72% of them. Twelve children had clinical symptoms of atopy, confirmed by skin prick-tests, versus 21 in control group [p=0.06]. Four of them had asthma, versus 11 in control group [p=0.005]. There was no significant difference between the two groups for rhino-conjunctivitis. This study shows that early childhood tuberculosis does not protect against atopy. But it seems that asthma occurs less frequently in case of early childhood tuberculosis. These results confirm recent experimental and epidemiological studies that suggest that mycobacterium tuberculosis decreases the risk of asthma, and need to be confirmed by largest studies in our country