Abstract
BACKGROUND: Because of the counter-regulation of Th1 and Th2 cells, Th1-type autoimmune diseases like thyroid autoimmunity and Th2-mediated allergic diseases like atopic dermatitis (AD) should occur in mutually exclusive populations. However, thyroid autoimmunity has been associated with chronic urticaria, and atopy is considered a cause of both AD and urticaria. OBJECTIVES: To assess the frequency of thyroid autoimmunity in children with AD and to study the correlation between the clinical severity of AD using the SCORing Atopic Dermatitis (SCORAD) score, and biochemical parameters of serum immunoglobulin E (IgE), absolute eosinophil count, and vitamin D levels. MATERIALS AND METHODS: A hospital-based cross-sectional study was conducted, recruiting children (0-18 years) with AD. Patients on drugs affecting thyroid dysfunction and those with sick euthyroid syndrome or an immunodeficiency disorder were excluded. Clinical severity was assessed using SCORAD, and the thyroid profile, anti-thyroid peroxidase antibodies, antinuclear antibody (ANA), absolute eosinophil count, serum IgE, and vitamin D levels were measured. RESULTS: Thyroid autoimmunity was diagnosed in 18.9% (10/53) of children. There was a significant correlation between SCORAD and serum IgE (r = 0.432, P = 0.002) and absolute eosinophil count (r = 0.575, P = <0.001). There was a negative correlation between SCORAD and vitamin D levels (r = -0.373, P = 0.006). CONCLUSIONS: Thyroid autoimmunity may be associated with AD, and a high index of suspicion is essential. Vitamin D also should be supplemented in children with AD as it is frequently found to be low, especially in severe cases. Multi-center case-control studies are required to determine the prevalence of thyroid autoimmunity in children with AD.