KOEBNER PHENOMENON: DISEASES, FACTORS, INHIBITION - MEDICINE - 2024

The isomorphic Koebner phenomenon was described by Heinrich Koebner in 1877 in patients with psoriasis. Koebner observed that people with psoriasis who injured areas of healthy skin, quickly developed lesions typical of their disease in those areas.

This same phenomenon was subsequently observed with many other dermatological diseases and has now been described for some dermatological diseases of infectious origin.

Psoriasis on the elbow (Source: Jacopo188 via Wikimedia Commons)

The mechanism by which this phenomenon occurs is still unknown. Cytokines, stress proteins, adhesion molecules, and antigens have been found involved, but the underlying pathophysiological mechanism has not been elucidated.

Koebner observed the phenomenon in areas of skin without psoriasis lesions in which abrasions, horse bites or tattoos occurred. The experimental mechanism used to reproduce this phenomenon is called the "Koebner experiment."

Later, some dermatologists thought that the phenomenon had an infectious or parasitic cause, since it responded well to the effect of treatments with potassium iodide, arsenic or pyrogallic acid.

For this reason, many dermatologists indicated sanitary measures such as washing clothes, beds and other waxes that could contain contaminants that could cause reinfection of the patient.

Diseases that present the Koebner isomorphic phenomenon

Although Koebner's phenomenon is a hallmark clinical hallmark of psoriasis, it has already been described in many other dermatoses.

The first description occurred in a young man suffering from vitiligo. She got the name of a young woman tattooed on her arm, in an injury-free area, when about six months later vitiligo lesions appeared on the tattoo.

The traumatic effect of light or heat has been known for a long time to exacerbate many skin diseases. For example, it is known that Darier disease lesions can be reproduced by exposing healthy skin to ultraviolet light.

However, some authors have thought that the latter phenomenon is nothing more than a Koebner phenomenon. To reinforce this theory, experiments have been done with cauterization, using candaridine, spray ethyl chloride, etc., trying to reproduce the lesions of Darier's disease.

The following is a list of some non-infectious and infectious dermatological diseases associated with Koebner's phenomenon (only some of the most common are included).

Non-infectious in origin

- Psoriasis

- Vitiligo

- Lichen planus

- Lichen nitidus

- Pityriasis rubra pilaris

- Vasculitis

- Darier's disease

- Pellagra

- Erythema multiforme

- Eczema

- Behçet's disease

- Pyodemus gangrenosum

- Bullous pemphigus

- Dermatitis herpetiformis

- Cutaneous mastocytosis

Of infectious origin

- warts

- Molluscum contagiosum

Predisposition and triggers

One of the characteristic aspects of psoriasis is that the location of the disease can be controlled experimentally. This is how some triggers can cause psoriasis lesions in susceptible individuals.

In these patients, koebnerization can cause florid psoriasis lesions in the face of many triggering stimuli, among which the following can be named:

-Insect bites or animal bites

-Burns

-Dermatitis

-Reaction to drugs

-Excoriations

-Incisions

- Lichen planus

-Lymphangitis

-Photosensitivity

-Pressure stress

-Ultraviolet light

-Vaccination

-Test on the skin (tuberculin injections, etc.)

-Irritants

These stimuli are not the cause of psoriasis, but the agent or event can strictly determine the location to which the psoriasis lesions will spread.

Period of appearance of lesions

The period necessary for psoriasis lesions or other diseases that present the koebnerization phenomenon to appear after an injury to healthy skin is variable, even for the same patient.

In a patient with psoriasis (which is the most studied condition) when several linear abrasions are made at the same time, psoriasis lesions will not appear in all the abrasions at the same time. These will appear in an interval of several days, but all will develop psoriasis lesions.

Psoriasis lesions in the dorsal region (Source: Psoriasis_on_back.jpg: User: The Wednesday Island (of the English Wikipedia) derivative work: James Heilman, MD via Wikimedia Commons)

In general, the time interval for koebnerization is between 10 and 20 days, but it can be as short as 3 days and as long as 2 years. This great variability shows the different sensitivity and the unique characteristics of the skin of each patient.

Preferential site

There are some changes in the areas of scarification of the skin that may explain the development of psoriasis lesions in these areas. Vascular changes and chronic mast cell infiltrate affecting endothelial cells around the injury can generate memory of the inflammatory event at the injury site.

There is no preference at the site of injury, that is, healthy skin lesions can involve any area and not specifically the scalp, elbows and knees, which are the most frequent sites for the spontaneous development of psoriasis.

How can the Koebner phenomenon be inhibited?

In order to delay or prevent the appearance of Koebner's phenomenon, various treatments have been used. The elucidation of the pathophysiological mechanisms involved in this phenomenon will be the only certain future measures for the adequate treatment of these lesions.

Some treatments have been used successfully that have delayed the appearance of Koebner's phenomenon, among these we will describe some.

Local injections of epinephrine that induce local vasoconstriction have been helpful. The application of liquid or soft white paraffin also has an inhibitory effect, perhaps because of the known antimitotic effect that soft ointments have on the skin.

Some authors have found evidence that local intradermal injections of serum from patients in the process of remission of active psoriasis lesions have an inhibitory effect on Koebner's phenomenon, but also generate remission of active lesions in the patient receiving the serum.

Pressure applied to the skin can prevent Koebner phenomenon. It has been reported that, in an area of ​​scarification of the skin of a patient with psoriasis, external pressure to close the local vessels in the first 24 hours after the injury prevents the appearance of psoriasis lesions in the area.

This mechanical effect is similar to the vasoconstrictor effect of adrenaline and suggests that there must be vasoactive substances that are released and are related to the isomorphic phenomenon, which under these conditions are not secreted.

The use of topical steroids or substances such as methotrexate, lidocaine, antimycin A or colchicine in topical or intradermal form, does not prevent or delay koebnerization.

References

1. Frederick Urbach. The negative effects of solar radiation: a clinical overview (2001) Elsevier Science BV
2. G Weiss, A Shemer, H Trau. The Koebner phenomenon: review of the literature. JEADV (2002) 16, 241–248
3. Lior Sagi, MD *, Henri Trau, MD. The Koebner phenomenon (2011) Clinics in Dermatology. 29, 231-236.
4. Robert AW Miller, MD The Koebner Phenomenon Review (1982) International Journal of Dermatology
5. Thappa, DM (2004). The isomorphic phenomenon of Koebner. Indian Journal of Dermatology, Venereology, and Leprology, 70 (3), 187.