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Abstract Atopic dermatitis is the commonest chronic cutaneous disease of childhood in the first years of life.It is an eczematous highly pruritic chronic inflammatory relapsing skin disease. Its presentation varies from an acute eczematous relapsing eruption in early life to a characteristic lichenified dermatitis in older patients. It often occurs in people with personal or family history of other atopic disease as bronchial asthma, rhinitis, and hay fever. The role of vitamin D in calcium homeostasis has been well recognized, studies have identified additional influences of vitamin D on the immune system, and several lines of evidence suggest a possible influence of vitamin D on prevalence of allergic diseases. Staphylococcus aureus is believed to play a significant role in the pathogenesis of atopic dermatitis,colonization with S. aureus is the most common skin infection in AD (90% of patients compared to 5% of normal individuals) and occurs on both lesional and, to a lesser extent, nonlesional AD skin. IgE elevation on peripheral eosinophilia are Th2 polarity indicators, characteristic in atopic patients, suggesting that Th2 cytokines can favor S. aureus colonization of the skin. In a proportion of AD patients who respond poorly to antiinflammatory treatment, persistent S. aureus colonization is associated with higher total IgE levels suggesting that IgE may contribute to an increased susceptibility to infection. vitamin D has been shown to induce cathelicidin expression in keratinocytes,that enhances antimicrobial activity against S. aureus. The aim of this study was to investigate serum level of 25(OH)D and specific IgE to Staphylococcus aureus in children with AD and their effect on the severity of the disease. Thirty patients were enrolled in the study (18 males and 12 females), their ages ranged from 1to 14 years. Complete history taking,dermatological and general examination, diagnosis as having AD by fulfilling the United Kingdom Working Party diagnostic criteria for AD, disease severity determination by SCORAD index and measurement of 25-hydroxy vitamin D and specific IgE to Staphylococcus aureus in the sera of the patients were performed. Twenty age and sex matched normal control subjects were also included in the study. The mean value of 25(OH)D was significantly lower in AD patients group compared to control group and (66.7 %) of the AD patients had insufficient or deficient vitamin D, suggesting a possible role of vitamin D deficiency in the pathogenesis and exacerbation of AD. In this study an inverse correlation between serum concentrations of 25(OH)D and severity of disease was found .The present study showed that patients with mild AD had significantly higher levels of vitamin D than patients with moderate and severe AD. The median values of specific IgE to Staphylococcus aureus increased in AD patients than in controls. There was a significant correlation between specific IgE to Staphylococcus aureus and the severity of AD. There was a significant correlation between vitamin D and specific IgE to Staphylococcus aureus, it was found that there is an increased prevalence of patients who were sensitive to Staphylococcus aureus in children with insufficient or deficient levels of 25(OH)D. In conclusion, vitamin D may be insufficient or deficient in a subset of atopic dermatitis children especially those with moderate and severe disease. Our data, showing a correlation between vitamin D deficiency and severity of AD in children, a significant correlation between specific IgE to Staphylococcus aureus and the severity of AD and a significant correlation between vitamin D and specific IgE to Staphylococcus aureus. |