6 Frequently Asked Questions about Koebner Phenomenon

If you have plaque psoriasis, you might notice plaques on the same parts of your body again and again. However, have you ever injured an area of plaque-free skin and then noticed new plaques forming? If so, you may be experiencing Koebner Phenomenon.

Koebner Phenomenon is the development of psoriatic lesions (plaques) in previously unaffected skin after trauma or injury.1 For example, a person might be experiencing Koebner Phenomenon if they cut themselves shaving, and later notice new plaques forming around the cut. Still confused? Here are six frequently asked questions about Koebner Phenomenon.

How common is koebner phenomenon?

Koebner Phenomenon typically affects people with chronic skin conditions, such as psoriasis. Approximately 25% of psoriasis patients experience Koebner Phenomenon2, but this reaction can also impact people with skin conditions such as lichen planus or vitiligo.1 There are four major types of Koebner Phenomenon, the primary type being ‘true koebnerization," which affects psoriasis patients.2 For people with psoriasis, Koebner Phenomenon is more common during an active psoriasis flare.1 Additionally, Koebner Phenomenon occurs more commonly in the winter than in the summer.1

What triggers koebner phenomenon?

Koebner Phenomenon often occurs after there is trauma to the skin, such as a burn, insect bite, surgical incision, or from shaving.2 Friction to the skin can also trigger Koebner Phenomenon, like wearing uncomfortable shoes, an irritating belt buckle, or a chafing bra strap.3 Mild irritations, such as manicuring your nails, sucking your thumb, or even dying your hair, can also trigger this reaction.4 Some people experience Koebner Phenomenon after an allergic reaction, following a drug reaction, or even from certain therapeutics like UV light and irradiation.2

While there are many triggers for this reaction, people who experience Koebner Phenomenon from one trigger (such as trauma), usually experience it from other triggers too (such as an allergic reaction).2 For this reason, Koebner Phenomenon is often called the “all or none phenomenon”, because people who react to one thing usually react to others too.2 Koebner Phenomenon also occurs more frequently around areas of scar tissue, or when the person is experiencing emotional stress.2

Most people who experience Koebner Phenomenon typically see a new lesion form between 10 and 14 days after the skin is affected.1 However, for some patients, new lesions from Koebner Phenomenon can occur anywhere between 3 days and 2 years after the initial impact on the skin.2

What causes this?

Although Koebner Phenomenon is relatively common for people with chronic skin conditions, the exact cause is still unknown.1 Research suggests that Koebner Phenomenon may result from a nonspecific inflammatory reaction in combination with a disease-specific reaction, but the exact cause of this phenomenon is still a mystery.2

“Koebner Phenomenon” was named after Dr. Heinrich Koebner, the first doctor to document this reaction at the end of the 18th century.2 Dr. Koebner was a noted dermatologist, and he first noticed this reaction at the site of scrapes and abrasions, horse bites, and tattoos.1 Today, Koebner Phenomenon is also referred to as “Isomorphic Response.”2

How can I prevent and treat this?

Like psoriasis, Koebner Phenomenon cannot be prevented. However, to limit Koebner Phenomenon lesions, patients should focus on taking care of their skin, such as limiting sun exposure, and keeping the skin moisturized and clean.3 To limit Koebner Phenomenon, you should also clean and cover all wounds quickly, and avoiding picking or scratching at psoriasis plaques.4 To treat Koebner Phenomenon plaques, most patients use their normal psoriasis treatment regime. If you have concerns about treating Koebner Phenomenon, be sure to talk to your healthcare provider.

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