A pattern of association between clinical form of vitiligo and disease-related variables in a Brazilian population

Abstract

Vitiligo classification systems are often based exclusively on the number and distribution of the white patches. To what extend these classification protocols reflect possible different pathophysiological basis for vitiligo or carry any prognostic value is currently unknown. To investigate patterns of association between type of vitiligo and common disease-related variables, in order to advance on the understanding of the exact nature of different clinical forms of disease, as well as to identify features with prognostic value for clinical progression of early diagnosed vitiligo. This is a cross-sectional study of a population sample from south of Brazil composed of 586 independent vitiligo-affected individuals. Different strategies of case-control analysis were employed to test for association between the three most common vitiligo clinical types and age of onset, family history of vitiligo, occurrence of Köebner phenomenon (KP) and presence of autoimmune co-morbidity. Individuals affected by segmental vitiligo showed lower average age of onset (16 years) when compared with vulgaris (23.9 years) and acrofacial cases (29 years) (p<0.001). The distribution of occurrence of KP, family history of vitiligo and co-occurrence of autoimmune disease followed a gradient pattern, with high, intermediate and low chance of occurrence of all three variables observed for vulgaris, acrofacial and segmental vitiligo, respectively (p<0.001 for overall distribution). Results indicate a uniform pattern of association between vitiligo clinical forms and KP, positive vitiligo family history and occurrence of co-morbidity autoimmune. The impact of the observed pattern of association over disease prognosis and classification is discussed.