vitiligo is a generalized autoimmune disease manifesting acquired white patches due to loss of melanocytes . it is the most prevalent pigmentary disorder with an incidence rate between 0.1 and 2% showing multifactorial etiology and polygenic inheritance . autoimmune disorders , genetic factors , autotoxic metabolites of melanin synthesis , accumulation of neurochemical substances , biochemical imbalance with defective free radical defense , deficiency in melanocyte growth factors , and an intrinsic defect of structure and function of melanocytes have been proposed to be involved in its pathogenesis . vitiligo is frequently associated with various organ - specific autoimmune diseases , such as , hashimato 's thyroiditis , addison 's disease , diabetes mellitus type 1 , and pernicious anemia . the aim of this study is to determine the prevalence of thyroid diseases in children with vitiligo and compare it with the literature . the study was conducted retrospectively in children with nonsegmental vitiligo , who applied to the pediatric dermatology clinic between april 2008 and january 2010 . the patients thyroid function tests and thyroid autoantibody results were enrolled without considering the extent of the vitiligo lesions . free triiodothyronine ( ft3 ) ( reference range : 2.53 - 5.22 g / ml ) , free thyroxine ( st4 ) ( reference range : 0.90 - 1.67 ng / dl ) thyroid stimulating hormone ( tsh ) ( reference range : 0.66 - 4.14 lu / ml ) , thyroglobulin antibody ( tgab ) ( positive titration > 115 iu / ml ) , and thyroid peroxidase antibody ( tpoab ) ( positive titration > 34 iu / ml ) ( roche diagnostics gmbh , mannheim , germany ) levels were interpreted . descriptive statistics were used to evaluate the findings and the t test was used to compare the rates ( spss version 16.0 , chicago , il , usa ) . a total of 79 pediatric patients with vitiligo whose ages ranged between two and fifteen were enrolled in the study . twenty - nine ( 36.7% ) patients were male and 50 ( 63.3% ) patients were female ( female : male = 1.7:1 ) . nineteen ( 24.0% ) patients were between the ages of two and five , ( 45.5% ) patients were between the ages of six and ten , and 24 ( 30.3% ) patients were between the ages of 11 and 15 [ table 1 ] . age distribution of pediatric patients with vitiligo abnormalities of thyroid function tests and thyroid autoantibodies were found in a total of 20 ( 25.3% ) patients ; eight males ( 40.0% ) and 12 ( 60.0% ) females . the abnormality of thyroid autoantibodies was found in a total of nine ( 11.3% ) patients ; three ( 33.3% ) males and six ( 66.7% ) females . tgab positivity was present in eight ( 10.1% ) patients and tpoab positivity was present in five ( 6.3% ) patients . the positivity of these two antibodies together was present in a total of four ( 5.1% ) patients . of the 20 patients in whom thyroid function tests and/or thyroid antibodies were abnormal , ten ( 12.6% ) had a high tsh level and normal ft3 and ft4 levels and were evaluated as subclinical hypothyroidism . one ( 1.2% ) patient had both low tsh and ft4 levels and was evaluated as hypothyroidism . one ( 1.2% ) patient had low ft4 and high tsh levels with tpoab positivity and was evaluated as hypothyroidism and autoimmune thyroiditis . five ( 6.3% ) patients had only autoantibody positivity ( three patients with both tgab and tpoab positivity and two patients with only tgab positivity ) and were evaluated as euthyroidism and autoimmune thyroiditis . three ( 3.7% ) patients had high tsh levels with autoantibody positivity ( one patient with both tgab and tpoab positivity and two patients with only tgab positivity ) and were evaluated as subclinical hypothyroidism and autoimmune thyroiditis . consequently , subclinical hypothyroidism was the most frequent diagnosis established in 13 ( 16.4% ) of the 79 pediatric patients with vitiligo [ table 2 ] . laboratory findings and clinical diagnoses of pediatric vitiligo patients in whom abnormal thyroid function tests and/or thyroid antibodies were detected statistically , there was no significant difference between male and female patients when they were compared for thyroid function tests and thyroid antibody abnormalities ( p = 0.728 ) . also , there was no significant difference between male and female patients when they were statistically compared for autoimmune thyroiditis ( p = 0.826 ) . it is more predominant in younger ages and approximately 50% of the cases have the onset of their disease prior to the age of 14 years . vitiligo affects both the sexes equally , but women more frequently visit the doctor due to cosmetic reasons . in this study of children with vitiligo a female preponderance ( female : male = 1.7:1 ) was present . vitiligo has been reported to start between 8 and 12 years of age in 51% of the children . this study showed that 45.5% of the children with vitiligo were between 6 and 10 years of age . autoimmunity is one hypothesis forwarded to explain nonsegmental vitiligo . a specific cytotoxic t - cell reaction , either of primary origin or resulting from damage to melanocytes by other mechanisms has been suggested to be responsible for destroying the pigment cells . a genetic predisposition to immune dysregulation can lead to aberrant t - cell reactivities that destroy melanocytes . alternatively , autoreactive antimelanocyte t - cells can arise in response to a challenge to the immune system . involvement of the immune system in the pathogenesis is evidenced by the effectiveness of immunomodulatory agents , such as , corticosteroids and calcineurin inhibitors . on the other hand , segmental vitiligo is explained by the neural theory , which proposes that some chemical released from the peripheral nerve endings causes a decreased production of melanin . vitiligo is epidemiologically associated with other autoimmune diseases suggesting that predisposition to other autoimmune diseases involves a shared genetic component . particularly , an increased frequency of clinical as well as subclinical thyroid disease appears to be increased in frequency in patients with vitiligo . increased prevalence of autoimmune disorders in association with vitiligo and detection of various autoantibodies , including anti - thyroid and anti - melanocyte antibodies , in the serum of vitiligo patients and alteration of t - cell population showing decreased t - helper cells , are in favor of this autoimmune theory . vitiligo frequently precedes the thyroid involvement ; thus screening vitiligo patients for thyroid function and thyroid antibody seems plausible . autoimmune thyroid diseases accompany vitiligo , from which hypothyroidism is one of the most common disorder . in pediatric patients with vitiligo iacovelli et al . , reported a figure of 10.7% in children with nonsegmental vitiligo , especially in females , all of whom had thyroid dysfunction . hashimato 's thyroiditis was reported to be the most common autoimmune disease seen in patients with vitiligo . in a study of children and adolescents with vitiligo , hashimato 's thyroiditis was found to be two - and - a - half times and hypothyroidism ten times more frequent than in a healthy age - and - sex - matched population and 24.1% of these 54 patients with vitiligo had autoimmune thyroiditis as compared to 9.6% of school - aged children from an iodine - replete area of greece . yang et al . , reported that 11.8% of 363 pediatric vitiligo patients had abnormal levels of thyroid parameters . the thyroid abnormality prevalence of 25.3% determined in our study is compatible with the literature attracting attention to the association of thyroid disease and vitiligo in childhood . also , of the 20 patients in whom a thyroid abnormality was determined , 13 ( 16.4% ) had subclinical hypothyroidism and nine ( 11.3% ) had thyroid autoantibody positivity . dave et al . , showed that the frequency of thyroid disorders were 57.1% in adult patients with vitiligo in comparison to 10% in people without vitiligo . manighalam et al . , conducted a study on 30 patients with vitiligo , and they found hyperthyroidism and hypothyroidism in 10 and 6.6% , respectively . another study reported that an antithyroid antibody was detected in 18.1% of the patients with vitiligo in comparison to 7.3% in the control group , with more prevalence in females . subclinical hypothyroidism is characterized by an elevated serum tsh level associated with a normal total or free t4 and t3 values . subclinical hypothyroidism is a laboratory diagnosis with no significant findings or symptoms associated with thyroid dysfunction in patients . long - term follow up has demonstrated the development of overt hypothyroidism at a rate of 5 - 20% per year , especially in autoimmune thyroiditis . when we consider that the prevalence of subclinical hypothyroidism is < 2% in the pediatric age group , the rate found in our study was higher . this retrospective study of prevalence attracts attention to the association of vitiligo with thyroid abnormalities . as the risk of developing overt hypothyroidism is high in patients with subclinical hypothyroidism , we suggest that thyroid function tests and thyroid autoantibodies be analyzed in children with vitiligo .