title: Inverse association between Mycobacterium tuberculosis infection and atopic rhinitis in children.
abstract: BACKGROUND
  The association between Mycobacterium tuberculosis (MTB) infection and atopy remains controversial.
  
  
  OBJECTIVE
  To investigate the association between MTB infection and atopic rhinitis in children living in a high TB incidence area.
  
  
  METHODS
  In this cross-sectional study 418 children aged 6-14 years from an established epidemiological research-site in a poor urban community were invited to participate. They were assessed for allergic rhinitis (ISAAC questionnaire) and skin responses to tuberculin and eight environmental allergens. The presence of a BCG scar was documented, intestinal parasites and total and Ascaris lumbricoides-specific IgE levels were measured. Atopic rhinitis was defined, using the new World Allergy Organization (WAO) definition, as reported allergic rhinitis and a positive skin prick test (SPT > or =3 mm) to any allergen.
  
  
  RESULTS
  Among the 337 children enrolled 10.4% had allergic rhinitis, 17.5% a positive SPT and 53% a positive tuberculin skin test (TST > or =10 mm). Children with a positive TST were significantly less likely to have recent atopic rhinitis (OR(adjusted) 0.06; 95% CI 0.007-0.5) than those with a negative TST. SPTs were significantly more common in children with negative TST who had recent allergic rhinitis (OR(adj) 34.0; 95% CI 7.6-152.6), but not in children with positive TST and recent allergic rhinitis (OR(adj) 0.6; 95% CI 0.07-5.2).
  
  
  CONCLUSIONS
  MTB infection seems to reduce the prevalence of atopic rhinitis, and influences SPT reactivity in children with allergic rhinitis from a high TB incidence area.
authors.affiliation: Department of Paediatrics and Child Health, Centre for TB Research and Education, Faculty of Health Sciences, Stellenbosch University, South Africa.
authors.forename: C C
authors.initials: CC
authors.lastname: Obihara
authors.forename: N
authors.initials: N
authors.lastname: Beyers
authors.forename: R P
authors.initials: RP
authors.lastname: Gie
authors.forename: P C
authors.initials: PC
authors.lastname: Potter
authors.forename: B J
authors.initials: BJ
authors.lastname: Marais
authors.forename: C J
authors.initials: CJ
authors.lastname: Lombard
authors.forename: D A
authors.initials: DA
authors.lastname: Enarson
authors.forename: J L L
authors.initials: JL
authors.lastname: Kimpen
mesh_terms: D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D006801:Humans; D009169:Mycobacterium tuberculosis; D012220:Rhinitis / Q000150:complications / Q000276:immunology*; D012882:Skin Tests; D013019:South Africa; D014376:Tuberculosis / Q000150:complications / Q000276:immunology*; D014505:Urban Population