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Background & Objective: Atopic diseases are one of the most common chronic conditions in children. A population based matched study was conducted to estimate the prevalence of atopic diseases and this study used to identify its correlations in primary school children aged 6-12 years in Shiraz (Southern Iran). Materials & Methods: This case-control study was carried out in 2228 primary school children. The children were selected using 2-stage random sampling from the 4 educational distrincts of for each child. The consultant physician examined the children with positive result. After diagnosis of eczema, utricaria and allergic rhinitis control groups were selected by using matching method (Age, sex, school). The correlations of atopic diseases were determined by conditional logestic regression. Results: The most important results were as follow: Prevalence of diagnosed allergic rhinitis, utricaria and eczema in primary school children estimated in order 5.2% (Boys: 5.2% & girls: 5.12%), 3.6% (Boys: 3.57% & girls: 3.7%) and 1.6% (Boys: 1.53% & girls: 1.7%). There was no significant association between atopic diseases and birth order, social class, parent’s education, parent’s smoking and period of breast-feeding. An increased risk of childhood atopic diseases were associated with familiar history of allergic rhinitis (P<0.05), familiar history of utricaria (P<0.05) and familiar history of eczema (P<0.05). Conclusion: Our study confirmed that familiar atopic diseases were significant predictors of childhood allergic rhinitis, utricaria and eczema among school children in Shiraz.

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Background and Objective: The interleukin-18 (IL-18) gene on chromosome 11 has been suggested as a susceptibility factor for allergies. It is a member of the IL-1 family that was originally described as interferon (IFN-γ)–inducing factor. IL-18 might initiate Th2 responses with production of IgE via the stimulation of IL-4 and IL-13 synthesis in mast cells and in basophil and eosinophil recruitment, such as allergic inflammation. This study was done to assess the association of Interleukin-18 gene polymorphism -137G/C with allergic rhinitis. Methods: This case-control study was performed on 293 allergic rhinitis patients and 218 healthy control volunteers .The IL-18 polymorphism was analyzed by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. Results: The frequency of the GG, GC and CC genotypes were 64.2%, 32.1% and 3.7% in healthy controls and 60.1%, 35.5% and 4.4% in allergic rhinitis patients, respectively. This diference was not significant. Conclusion: This study suggests that IL-18 polymorphism gene -137G/C may not be participated as a risk factor in the pathogenesis of allergic rhinitis.