Koebner Phenomenon

Koebner Phenomenon

[This phenomenon is also termed the isomorphic response]

Appearance of new skin lesions on previously unaffected skin secondary to trauma.
Koebner phenomenon seen in –

  1. Psoriasis,
  2. Vitiligo,
  3. Lichen planus


Koebnerization – function as a clinical indicator of disease activity in vitiligo, as well as serve as a predictor of treatment response


Other conditions have demonstrated the Koebner phenomenon

  1. leukocytoclastic vasculitis
  2. mycosis fungoides
  3. eruptive xanthomas

Classification and Subtypes of the Koebner Phenomenon

Boyd and Nelder classified

First group [category I] referred to as true koebnerization,

  1. psoriasis,
  2. lichen planus,
  3. vitiligo.

Koebner phenomenon is reproducible in all patients by a variety of insults.

Boyd and Nelder argued that the term Koebner phenomenon should be typically reserved for this group of diseases.

Second group [category II] –pseudo-koebnerization,

  1. molluscum contagiosum
  2. verruca vulgaris

whereby the Koebner phenomenon gets produced by the seeding of infectious agents along with sites subjected to trauma, usually from scratching.

Third group [category IIII],  occasional lesions,

  1. Darier disease
  2. Erythema multiforme,

which meet some criteria for the Koebner phenomenon but not all.

Fourth group [category IV] – questionable trauma-induced process, includes all disorders with a dubious association with trauma, such as pemphigus vulgaris and lupus erythematosus.

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