There is an inverse association between Mycobacterium tuberculosis infection and atopic rhinitis in children but not in the prevalence of IgE sensitization in a poor urban community

The aim of this study was to investigate the association between Mycobacterium tuberculosis (MBT) infection and atopic rhinitis in children recruited from a community with high incidence of MTB infections. The children were assessed for rhinitis according to the ISAAC questionnaire and tested for MTB infection by the tuberculin skin test (TST). Allergen-specific IgE sensitizations were tested by using eight common allergens. Atopic rhinitis was defined as reported rhinitis symptoms and presence of IgE sensitization. The prevalence of IgE sensitization was low but did not differ significantly in relation to positive TST, household income or parasite infection. However, children with a positive TST were significantly less likely to have atopic rhinitis than those with negative TST (0.6% vs. 7.0%). TST-negative children reporting recent rhinitis symptom were significantly (p<0.001) more often IgE-sensitized compared to TST-positive children. The adjusted odds ratio to have atopic rhinitis in TST-positive children compared to TST-negative was very low (OR adj: 0.06, 95% CI 0.007-0.5). In summary, the authors could show a difference between TST-positive and TSTnegative children in relation to atopic rhinitis but not to the prevalence of IgEsensitization in general. However, allergic children with MTB infection showed a reduced SPT reactivity. The authors conclude that earlier conflicting results for an inverse association between MTB infection and atopic disease may be due to the use of different definitions of atopy. Citation: Obihara CC et al. Inverse association between Mycobacterium tuberculosis infection and atopic rhinitis in children. Allergy 2005; 60:1121-5.