Abstract
Koebner phenomenon regards the formation of a psoriatic lesion after a trauma, including tattoo, insect bite or other injuries. Although this manifestation is not specific for psoriasis, physicians should be aware because early recognition may be helpful in making the diagnosis when present.
Keywords: colostomy bag, Koebner phenomenon, peristomal skin, psoriasis
Koebner phenomenon regards the formation of a psoriatic lesion after a trauma, including tattoo, insect bite, or other injuries. Although this manifestation is not specific for psoriasis, physicians should be aware because early recognition may be helpful in making the diagnosis when present.
1. INTRODUCTION
A 69‐year‐old woman presented with a 10‐day history of an asymptomatic peristomal plaque. A large erythematous scaly plaque, 10 cm. in diameter, with sharply demarcated borders, was observed on the left abdominal side, around the stoma (Figure 1).
FIGURE 1.
Well‐defined psoriatic plaque around the stoma
What is you diagnosis?
2. DISCUSSION AND OUTCOMES
The patient had colostomy 2 years before to treat a colonic perforation due to a complication following aortic abdominal aneurysm. She reported mild psoriasis for approximately 10 years without specific treatment, but using topical steroids occasionally. The diagnosis of psoriasis following Koebner phenomenon (KP) was made. 1 , 2
Koebner phenomenon, also known as isomorphic response, describes the sudden occurrence of an inflammatory dermatosis, including psoriasis, lichen planus, vitiligo, or lupus erythematosus, on previously unaffected skin after traumatic stimuli (Table 1). This phenomenon has been reported after tattoo, burns, frostbite, insect bites, surgery, wounds or in old scars of sarcoidosis and smallpox vaccination (Table 2). The pathogenetic mechanisms of KP are still unclear, as to whether these manifestations are limited to the skin and mucosae, or may arise on internal organs is further questioning. 3 All physicians should be aware that traumatic episodes must be avoided in people with underlying immunological diseases.
TABLE 1.
Cutaneous manifestations of Koebner phenomenon
| Psoriasis |
| Lichen planus |
| Vitiligo |
| Lupus erythematosus (discoid) |
| Erythema multiforme |
| Molluscum contagiosum |
| Warts |
TABLE 2.
Causes of Koebner phenomenon
| Burns |
| Insect bites |
| Tattoo |
| Surgical procedures |
| Friction/excoriation |
| Laceration/scarification |
CONFLICT OF INTEREST
The authors have no conflict of interest.
AUTHOR CONTRIBUTIONS
MLP, DA, MP, and ADA: All authors have participated in the work, giving substantial contributions to conception and design, acquisition of data, drafting the manuscript, and final approval of the version to be published.
La Placa M, Abbenante D, Pazzaglia M, Di Altobrando A. A peristomal plaque of sudden occurrence. Clin Case Rep. 2021;9:2477–2478. 10.1002/ccr3.3939
REFERENCES
- 1. Yong‐Zhi J, Shi‐Rui L. Koebner phenomenon leading to the formation of new psoriatic lesions: evidences and mechanisms. Biosci Rep. 2019;39(12):BSR20193266. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2. Sagi L, Trau H. The Koebner phenomenon. Clin Dermatol. 2011;29(2):231‐236. [DOI] [PubMed] [Google Scholar]
- 3. La Placa M, Passarini B. Subacute cutaneous lupus erythematosus after a tattoo. Clin Exp Dermatol. 2009;34(5):632‐633. [DOI] [PubMed] [Google Scholar]