Halo Naevi and the Koebner phenomenon

The Koebner phenomenon (KP) is vitiligo that develops in an area of skin that has been affected by localized, often moderate trauma, such as an injury. Ghent University’s Dr. N van Geel and colleagues investigated this phenomenon (see British Journal of Dermatology 2012;167:1017-24.). They devised a new approach for assessing KP that took into account both the history and clinical examination of vitiligo patients; this appears to be a viable and beneficial tool for assessing KP in daily practice.

The findings back up the theory that KP can be used to assess and forecast the progression of vitiligo.

Halo naevi are common moles that have a white ring around them, indicating vitiligo-like pigment loss. Dr. van Geel and his colleagues investigated whether these moles appear together with vitiligo or separately (British Journal of Dermatology 2011; 164: 743-9). Their findings support the hypothesis that halo naevi can be a separate disorder, but that it can also be an initial element in the pathogenesis of vitiligo in a subgroup of persons.