What is the Koebner Phenomenon?

The Koebner phenomenon was first described by Heinrich Koebner (1838-1904), one of the outstanding dermatologists of the 19th century. His initial observations and studies resulted from having seen patients who had developed psoriasis at sites of excoriations, horse bites, and tattoos and he first published his findings in 1876. However, the definition has been extended to include lesions developed after trauma in people with no pre-existing dermatosis. Several other skin diseases e.g. lichen planus, vitiligo and Darier disease, can also present with Koebner phenomenon. Koebner phenomenon occurs in about 25% of people with psoriasis after various traumatic injuries, but this may be much higher as patients may not recognize the original traumatic episode (e.g. insect bite) and therefore the Koebner effect may go unreported. 1

Koebner response may follow:
(1)     mechanical or thermal trauma – due to animal bites, burns, electrodessication, excoriation, freezing, friction, gunshot wounds,            insect bites, lacerations, nail manicuring, poor fitting shoes, pressure, shaving, surgical grafts, surgical incision, tape stripping,                  thumb sucking, x-rays, sunburn, tattoos (injury). 2

Bellybutton PsoriasisTattoo psoriasisPsoriasis after surgery

         Psoriasis after Belly Ring Piercing                                          Psoriasis after a Tattoo                                       After removal of Benign Growth

 

(2)  dermatoses – skin conditions e.g. carbuncles/furuncles (boils and/or cysts), dermatitis, dermatitis herpetiformis, dermatophytosis,          diaper dermatitis secondary to Candida infection, eczema, epidermal inclusion cyst, folliculitis, herpes simplex, herpes zoster,                   lichen planus, lymphangitis, measles, miliaria, perianal neuro   dermatitis, pityriasis rosea, psoriasis, scabies, seborrheic dermatitis,              varicella, vitiligo. 2

Psoriasis after Herpes Zoster

                  Psoriasis after herpes Zoster     

    

(3)     allergic or irritant reactions – following Bacillus Calmette–Guérin (BCG) vaccination (tuberculosis), tuberculin skin test, hair                   spray, hair tints, influenza   vaccination, photosensitivity, positive patch testing, scratch skin test, tattoos (allergic reaction to ink),                 urticaria 2 , and

(4)     therapy – such as Grenz ray therapy – “ultrasoft” or “soft” radiation, roentgen radiation therapy, iodine application, ultraviolet light            (PUVA). 2

Psoriatic lesions usually form within 10-20 days of the wounding event (but may range from 3 days to 2 years). However, it usually coincides with the duration of the wound healing phase. This strongly suggests that skin in predisposed individuals may continue to develop normally right up until the substantial triggering skin trauma. 3,4

 

REFERENCES

  • Arias-Santiago A. et al.; The Koebner phenomenon: psoriasis in tattoos; CMAJ, April 16, 2013, 185(7)
  • Thappa DM. The isomorphic phenomenon of Koebner. Indian J Dermatol Venereol Leprol 2004;70:187-9
  • Matovi? L. et al.; The Koebner phenomenon, a prognostic sign of PUVA therapy effectiveness in patients with     psoriasis vulgaris–yes or no?; Med Pregl. 1999 Nov-Dec;52(11-12):437-40.
  • Chee Ren Ivan Lam et al.; Wound Repair Studies Reveal New Insights to Psoriasis; http://www.intechopen.com/