The Koebner phenomenon or Köbner phenomenon (, ), also called the Koebner response or the isomorphic response, attributed to

Heinrich Köbner Heinrich Koebner (German spelling Köbner); (2 December 1838 – 3 September 1904) was a German-Jewish dermatologist born in Breslau. He studied medicine in Berlin, earning his doctorate in 1859 at Breslau. Afterwards he performed hospital ...

, is the appearance of

skin lesion A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of th ...

s on lines of trauma. The Koebner phenomenon may result from either a linear exposure or irritation. Conditions demonstrating linear lesions after a linear exposure to a causative agent include:

molluscum contagiosum Molluscum contagiosum (MC), sometimes called water warts, is a viral infection of the skin that results in small raised pink lesions with a dimple in the center. They may become itchy or sore, and occur singularly or in groups. Any area of the sk ...

wart Warts are typically small, rough, hard growths that are similar in color to the rest of the skin. They typically do not result in other symptoms, except when on the bottom of the feet, where they may be painful. While they usually occur on the ...

s and toxicodendron dermatitis (a

dermatitis Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can ...

caused by a genus of plants including poison ivy). Warts and molluscum contagiosum lesions can be spread in linear patterns by self-scratching (" auto-inoculation"). Toxicodendron dermatitis lesions are often linear from brushing up against the plant. Causes of the Koebner phenomenon that are secondary to scratching rather than an infective or chemical cause include

vitiligo Vitiligo is a disorder that causes the skin to lose its color. Specific causes are unknown but studies suggest a link to immune system changes. Signs and symptoms The only sign of vitiligo is the presence of pale patchy areas of depigmen ...

psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small, localized patches to complete ...

lichen planus Lichen planus (LP) is a chronic inflammatory and immune-mediated disease that affects the skin, nails, hair, and mucous membranes. It is not an actual lichen, and is only named that because it looks like one. It is characterized by polygonal, fla ...

lichen nitidus Lichen nitidus is a chronic inflammatory disease of unknown cause characterized by 1–2 mm, discrete and uniform, shiny, flat-topped, pale flesh-colored or reddish-brown papules that may appear as hypopigmented against dark skin. Occasion ...

pityriasis rubra pilaris Pityriasis rubra pilaris refers to a group of chronic disorders characterized by reddish orange, scaling plaques and keratotic follicular papules.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. ...

, and keratosis follicularis (Darier disease).

Definition

The Koebner phenomenon describes skin lesions which appear at the site of injury. It is seen in: :*

Psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small, localized patches to complete ...

Pityriasis rubra pilaris Pityriasis rubra pilaris refers to a group of chronic disorders characterized by reddish orange, scaling plaques and keratotic follicular papules.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. ...

Lichen planus Lichen planus (LP) is a chronic inflammatory and immune-mediated disease that affects the skin, nails, hair, and mucous membranes. It is not an actual lichen, and is only named that because it looks like one. It is characterized by polygonal, fla ...

Flat warts Flat warts, technically known as Verruca plana, are reddish-brown or flesh-colored, slightly raised, flat-surfaced, well-demarcated papule of 2 to 5 mm in diameter. Upon close inspection, these lesions have a surface that is "finely verrucou ...

Lichen nitidus Lichen nitidus is a chronic inflammatory disease of unknown cause characterized by 1–2 mm, discrete and uniform, shiny, flat-topped, pale flesh-colored or reddish-brown papules that may appear as hypopigmented against dark skin. Occasion ...

Vitiligo Vitiligo is a disorder that causes the skin to lose its color. Specific causes are unknown but studies suggest a link to immune system changes. Signs and symptoms The only sign of vitiligo is the presence of pale patchy areas of depigmen ...

Lichen sclerosus Lichen sclerosus (LS) is a chronic, inflammatory skin disease of unknown cause which can affect any body part of any person but has a strong preference for the genitals (penis, vulva) and is also known as balanitis xerotica obliterans (BXO) when ...

:* Elastosis perforans serpiginosa :*

Kaposi sarcoma Kaposi's sarcoma (KS) is a type of cancer that can form masses in the skin, in lymph nodes, in the mouth, or in other organs. The skin lesions are usually painless, purple and may be flat or raised. Lesions can occur singly, multiply in a limite ...

Necrobiosis lipoidica Necrobiosis lipoidica is a necrotising skin condition that usually occurs in patients with diabetes mellitus but can also be associated with rheumatoid arthritis. In the former case it may be called necrobiosis lipoidica diabeticorum (NLD). NLD oc ...

:* Lupus :*

Juvenile Idiopathic Arthritis Juvenile idiopathic arthritis (JIA) is the most common, chronic rheumatic disease of childhood, affecting approximately one per 1,000 children. ''Juvenile'', in this context, refers to disease onset before 16 years of age, while ''idiopathic'' r ...

:* Still disease :*

Cutaneous leishmaniasis Cutaneous leishmaniasis is the most common form of leishmaniasis affecting humans. It is a skin infection caused by a single-celled parasite that is transmitted by the bite of a phlebotomine sand fly. There are about thirty species of '' Leish ...

Post kala azar dermal leishmaniasis Leishmaniasis is a wide array of clinical manifestations caused by parasites of the trypanosome genus '' Leishmania''. It is generally spread through the bite of phlebotomine sandflies, '' Phlebotomus'' and '' Lutzomyia'', and occurs most ...

A similar response occurs in

pyoderma gangrenosum Pyoderma gangrenosum is a rare, inflammatory skin disease where painful pustules or nodules become ulcers that progressively grow. Pyoderma gangrenosum is not infectious. Treatments may include corticosteroids, ciclosporin, infliximab, or cana ...

and Behcet's syndrome, and is referred to as pathergy. Rarely Koebner phenomenon has been reported as a mechanism of acute myeloid leukemia dissemination. Warts and molluscum contagiosum are often listed as causing a Koebner reaction, but this is by direct inoculation of viral particles. The linear arrangement of skin lesions in the Koebner phenomenon can be contrasted to both lines of Blaschko and dermatomal distributions. Blaschko lines follow embryotic cell migration patterns and are seen in some mosaic genetic disorders such as

incontinentia pigmenti Incontinentia pigmenti (IP) is a rare X-linked dominant genetic disorder that affects the skin, hair, teeth, nails and central nervous system. It is named from its appearance under a microscope. The disease is characterized by skin abnormalitie ...

and pigment mosaicism. Dermatomal distributions are lines on the skin surface following the distribution of spinal nerve roots. The rash caused by herpes zoster ( Shingles) follows such dermatomal lines.

History

The Koebner phenomenon was named after the rather eccentric but renowned German dermatologist Heinrich KoebnerIn the anglicisation of a German word, double vowels are often substituted for the Germanic umlaut on single vowels. The transformation of "Köbner" to "Kooebner" is just such a case. In the English literature, the umlaut is simply dropped and you often find "Köbner" simply as "Kobner". (1838–1904). Koebner is best known for his work in

mycology Mycology is the branch of biology concerned with the study of fungi, including their genetic and biochemical properties, their taxonomy and their use to humans, including as a source for tinder, traditional medicine, food, and entheogen ...

. His intense nature is illustrated by the following: in a medical meeting, he proudly exhibited on his arms and chest three different fungus infections, which he had self-inoculated, in order to prove the infectiousness of the organisms he was studying. The Koebner phenomenon is the generalized term applied to his discovery that on psoriasis patients, new lesions often appear along lines of trauma.

References

Sources

* Crissey JT, Parish LC, Holubar KH. Historical Atlas of Dermatology and Dermatologists. New York: The Parthenon Publishing Group, 2002. * Paller A, Mancini A. Hurwitz Clinical Pediatric Dermatology. Philadelphia: Elsevier Saunders, 2002. {{DEFAULTSORT:Koebner Phenomenon Dermatologic signs

Definition

History

See also

References

Sources