Clinical significance of Koebner phenomenon in vitiligo

Abstract

Background: The clinical significance of Koebner phenomenon (KP) in vitiligo with respect to disease activity and course is still debatable. Recently, a new classification was introduced for the assessment of KP.

Objectives: To evaluate the new assessment method for KP in clinical practice and to determine its clinical significance, both with respect to the clinical profile, course of vitiligo and treatment response.

Methods: Seven hundred patients with generalized vitiligo were included in this observational cohort study. KP was classified according to the new classification system into different subtypes [KP1, by history; KP2A and KP2B, by clinical examination (A, lesions on friction areas; B, linear, artefactual lesions)].

Results: KP1 was positive in 34·1% of the patients, 66·3% were KP2A positive and 15·1% showed KP2B. The body surface area (BSA) was significantly (P < 0·001) higher in the presence of any KP subtype and more disease activity was found in KP1-positive and KP2B-positive patients. An earlier age at onset and elevated risk of further depigmentation despite treatment were observed in all KP-positive groups. In KP2A- and KP2B-positive patients, depigmentation of wrists/ankles was more common. In the KP2A-positive group, a significantly higher prevalence of thyroid disease was found while autoimmune diseases were less prevalent in KP2B-positive patients.

Conclusion: The new assessment method for KP, taking into account both history and clinical examination, seems to be a useful and valuable tool for assessing KP in daily practice. Our results support the hypothesis that KP may function as a clinical parameter to assess and predict the clinical profile and course of vitiligo.