Thyroid Dysfunction in Non-segmental versus Segmental Vitiligo

Background: vitiligo is the most common pigmentation related disorder. Vitiligo is a one of the disorders of melanin pigmentation that affect approximately 0.5- 2% of the population. Both adults and children are affected with no predilection for sex or ethnicity. Although the pathogenesis of this disease is not fully understood, the autoimmune hypothesis is the most commonly accepted theory. The autoimmune thyroid abnormalities are the most common associations with NSV. One common feature of autoimmune thyroid diseasesisthe frequent presence of autoantibodies directed against thyroglobulin (TG) and thyroperoxidase (TPO). Associated thyroid dysfunction with NSV that may be at the subclinical or the clinical level, includes Graves’ disease, Hashimoto’s thyroiditis, hyper-thyroidism or hypothyroidism. Interestingly, vitiligo often precedes thyroid disease indicating a need for regular screening for thyroid dysfunction and thyroid-related antibodies. Objective: this study aimed to shed a light on the association between SV, NSV and the presence of TG Ab and TPO Ab. This study included thirty SV patients, thirty NSV patients and thirty age and sex matched individuals free from vitiligo as a comparative group. Estimation of serum anti-TPO, anti-TG, serum TSH and serum FT3 andFT4were done by using the ELISA kits. Subjects and Methods: in our study, most of the patients were of Fitzpatrick skin type IV. Two cases only had poliosis in NSV and five in SV patients. Koebner phenomenon was absent in SV patients while, there was 40% of NSV group of patients. Results: mean TSH levels were normal in all the studied subjects. FT3 showed a statistically significant difference between NSV patients and the comparative groups. There was a statistically significant increase in the prevalence of anti TPO antibody in NSV patients compared to the SV group and vitiligo free group. No statistically significant increase in the prevalence of anti TG among the comparative groups. The levels of anti TG and anti TPO levels show significant increase with duration of the disease, VASI score and female gender in NSV group. Conclusion: the presence of higher mean levels of anti-TPO in the NSV group compared to the SV group and vitiligo free group was in favor of the autoimmune pathogenesis hypothesis as they point to a disturbance in the autoimmune system of the NSV patients and this supporting the view that the pathogenesis of SV and NSV is different.