Koebner phenomenon

The isomorphic appearance of new lesions of an existing dermatosis on previously uninvolved skin following cutaneous trauma (e.g., friction, excoriation, surgery), representing a trauma-induced activation of the underlying inflammatory skin disease.

Causes

• Inflammatory dermatoses

  • Psoriasi

  • Lichen planus

  • Vitiligo

  • Atopic dermatitis

  • Lichen sclerosus

• Autoimmune and immune-mediated skin diseases

  • Systemic lupus erythematosus with cutaneous involvement

  • Dermatomyositis

• Infectious dermatoses (rarely described)

  • Viral skin infections where trauma facilitates lesion development

  • Warts (verruca) through autoinoculation after skin injury