Role of Koebner phenomenon in predicting the clinical profile and course of vitiligo.

Background: Koebner phenomenon (KP) is a clinical indicator of disease activity in vitiligo. Few studies have suggested that it may also be used to predict the clinical profile, prognosis, and response to therapy. Aims: To compare the clinical characteristics of vitiligo patients with different types of KP in an Indian population. Methods: A prospective longitudinal observational study was conducted from January to November 2016. Classification of KP was done according to the Vitiligo European Task Force guidelines into KP1-by history and KP2-by clinical examination (2A: lesions on friction areas and 2B: trauma-induced lesions). Results: Of the total 160 patients, KP was observed in 102 (63.8%) cases. Type 1 KP was seen in 43 (26.9%), type 2A in 87 (54.4%), and type 2B in 34 (21.3%) cases. Patients with KP1 and KP2B had an earlier age of presentation and disease onset, while those with KP2A had a higher age of presentation and disease onset. Incidence of other autoimmune disorders, higher BSA involvement and requirement of betamethasone oral mini pulse therapy were significantly higher in cases with KP1 and KP2A, while significantly elevated anti-thyroid peroxidase levels were seen in cases with KP2A. Also, lesser treatment response was noted among cases with KP1 and KP2A. Conclusion: KP is associated with increased disease activity and more extensive involvement of vitiligo. Type 2A KP was associated with a higher incidence of other autoimmune disorders, more extensive disease, and the use of systemic steroids for treatment, which were not seen in KP2B. Thus, these groups might define two different subsets of patients. [ABSTRACT FROM AUTHOR]