Objective: To investigate the association between the experimentally induced Kobner phenomenon (KP-e) and the Kobner phenomenon by history (KP-h), disease activity, and therapeutic responsiveness in vitiligo vulgaris.
Design: Cohort study.
Setting: An outpatient clinic.
Patients: Sixty-one consecutive patients with vitiligo vulgaris.
Intervention: Three months after a standardized epidermodermal injury was induced, the KP-e was evaluated. For 1 year, UV-B (311 nm) therapy or topical fluticasone propionate plus UV-A therapy was given, depending on the severity of depigmentation.
Main outcome measures: The presence or absence of the KP-e and the KP-h disease activity as scored on a 6-point scale from -1 to +4 (vitiligo disease activity [VIDA] score) and therapy-induced repigmentation grade.
Results: Nineteen (31%) of the patients had a positive KP-h, whereas 37 (61%) showed a positive KP-e (P<.001). The VIDA score did not always predict a positive KP-e, although patients with a positive KP-e had a higher mean VIDA score (VIDA score of 1.6) than did patients with a negative KP-e (VIDA score of 0.5) (P<.001). The responsiveness to UV-B (311 nm) therapy among KP-e-positive or KP-e-negative patients was not significantly different (P=.66). However, KP-e-positive patients who were treated with fluticasone propionate plus UV-A showed a better response than did KP-e-negative patients (P=.01). Among patients responding to both therapies, VIDA scores were significantly decreased (P<.001) compared with VIDA scores before therapy.
Conclusion: The KP-e may function well as a clinical factor to assess present disease activity and may also predict the responsiveness to fluticasone propionate plus UV-A therapy but not to UV-B (311 nm) therapy.