Multivariate Analysis of Factors Associated with the Koebner Phenomenon in Vitiligo: An Observational Study of 381 Patients

Background: The Koebner phenomenon (KP) is a common entity observed in dermatological disorders. The reported incidence of KP in vitiligo varies widely. Although the KP is frequently observed in patients with viltiligo, the associated factors with KP has not been established yet. Objective: The aim is to estimate the prevalence of KP in vitiligo patients and to investigate the associated factors with KP among vitiligo characteristics. Methods: A cross-sectional observational study was conducted using 381 vitiligo patients. Demographic and clinical information was obtained via the completion of Vitiligo European Task Force (VETF) questionnaires. Patients with positive history of KP were extracted from this vitiligo database. Multivariate analysis was performed to assess associations with KP. Results: The median age of cases was 24 years (range, 0.6∼76). In total, 237 of the patients were male (62.2%). Vitiligo vulgaris was the most common type observed (152/381, 39.9%). Seventy-two percent (274/381) patients did not exhibit KP, whereas 28.1% (107/381) of patients exhibited this condition. Multivariable analysis showed the following to be independent factors with KP in patients with vitiligo: the progressive disease (odds ratio [OR], 1.82; 95% confidence interval [95% CI], 1.17∼2.92; p=0.041), disease duration longer than 5 years (OR, 1.92; 95% CI, 1.22∼2.11; p=0.003), and body surface area more than 2% (OR, 2.20; 95% CI, 1.26∼3.24; p＜0.001). Conclusion: Our results suggest that KP may be used to evaluate disease activity and investigate different associations between the clinical profile and course of vitiligo. Further studies are needed to predict the relationship between KP and responsiveness to therapy. (Ann Dermatol 29(3) 302∼306, 2017)