The Koebner phenomenon (isomorphic response) is seen in vitiligo. Which type of vitiligo does NOT show Koebnerisation?

• A Generalised (NSV)
• B Acrofacial
• C Segmental vitiligo ✓
• D Universal vitiligo

Explanation

Segmental vitiligo (SV) does NOT show the Koebner (isomorphic) phenomenon, which distinguishes it fundamentally from non-segmental vitiligo (NSV). SV follows a dermatomal or Blaschko distribution, progresses rapidly for 6–24 months then stabilises permanently, and does not koebnerise. It is thought to have a different pathomechanism—possibly somatic mosaicism rather than systemic autoimmunity—explaining why it responds poorly to immunosuppressants and better to surgical melanocyte transplantation.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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