What Is the Koebner Phenomenon, and What Can I Do About It? A Q&A with Dr. Truong

By Beth W. Orenstein
June 16, 2023

This article is part of a Q&A series in which a healthcare professional in our community answers your frequently asked questions.

We asked: “Why are new psoriasis plaques popping up in an area where I’ve been injured?”

Allison Truong, M.D.: Let’s say you have psoriasis plaques on your elbow or knees and then fall and scrape them—or you do yoga and put weight on your elbows and knees. Soon after, you notice that you have more plaques in those areas than you did before. This is what’s known as the Koebner, or Köbner, phenomenon.

It’s named for Heinrich Köbner, a physician who in the late 1800s described skin lesions happening in places of trauma or irritation. He explained it as an “isomorphic” response—meaning “equal shape.” Meaning, any new lesions that develop look the same as the lesions you’ve had in the past and aren’t considered a new or different skin condition.

The Koebner phenomenon can occur as a result of any type of trauma to the skin, including:

Many people living with psoriasis ask why this happens. The answer is simple: We don’t know. It doesn’t happen to everyone who has psoriasis, and it can happen suddenly after years of living with psoriasis and not experiencing it.

The Koebner phenomenon can happen in other skin conditions as well—for example, people with warts, vitiligo, and lichen planus can experience it, too.

The Koebner phenomenon is unpredictable. Some people can get 25 tattoos, and it doesn’t happen. Then, they get that 26th tattoo, and once it heals, they develop more psoriasis around the tattoo.

Psoriasis due to the Koebner phenomenon is treated in the same way you treat any psoriasis. Taking steps to manage your psoriasis symptoms can help minimize the effect of trauma to your skin. If you haven’t found an effective treatment for your psoriasis symptoms yet, please see a board-certified dermatologist.

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