We all get the occasional cut or scrape. You may burn your fingers or arm when cooking dinner or get a bug bite in the summertime. For most of us, these are simply a nuisance; even if they’re painful for a time, we know they will go away and our skin will heal. But for those with psoriasis, these skin irritations can trigger a new psoriasis site.
The Koebner Phenomenon
The Koebner phenomenon occurs when psoriasis plaques form at the site of a skin injury where psoriasis wasn’t present before. It is named after Dr. Heinrich Koebner, who noticed this phenomenon in the 19th century. Any skin injury that damages the dermis, which is the layer of skin below the surface, can cause psoriasis plaques to form. About one-fourth of individuals with psoriasis experience the Koebner phenomenon at some time, according to a report published in the Journal of Medicine and Life in 2014.
Causes of the Koebner Phenomenon
Scrapes and cuts that do not penetrate below the top layer of the skin usually do not cause additional lesions to appear. However, if the skin irritation damages the dermis, the layer directly below the top layer of skin, you might develop new lesions. Any type of skin injury can cause this including;
- Cuts, bruises, or scrapes
- Burns (including chemical burns and sunburns)
- Bug bites
- Poison ivy/poison oak
- Needles including injections, vaccinations, acupuncture, and tattoos
- Chicken pox or other rashes
Normally, a new lesion will appear anywhere between 10 and 20 days after an injury, although it can appear anywhere from three days to two years after the injury, according to The Koebner Phenomenon: Review of the Literature. You may be more at risk of developing new lesions if you have active psoriasis lesions at the time of your skin injury.
Can the Koebner phenomenon lead to psoriatic arthritis?
One study, completed in 2008 at the University of Manchester, found that a high percentage of people who developed psoriatic or other forms of inflammatory arthritis were more likely to have experienced a skin injury, had received the rubella vaccine, had recurrent oral ulcers, or a fractured bone. Because this association was highest in those that had experienced a skin trauma, the researchers speculated that it could be a “deep Koebner phenomenon.” They believe that the injury activated the immune system and thereby activated the inflammatory arthritis. They noted, however, that further studies are needed before drawing any conclusions.
Tips for Preventing Skin Injuries
Keeping your skin protected will help you avoid injuries. That might mean taking extra precautions when doing routine chores and activities, especially during a psoriasis flare. Here are some tips:
- Wear long sleeves and gloves when doing household chores, hiking, or gardening, especially if you are pruning plants and bushes or working with chemicals.
- Make sure to always use bug spray and keep skin covered with long sleeves when outdoors.
- Use warm water for showers and baths and never scrub your skin; instead use a soft wash cloth and pat your skin dry when done.
- Use moisturizers to avoid dry, itchy skin you are tempted to scratch.
- Keep your nails trimmed so you can’t accidently cut yourself if you do scratch your skin.
- Always use sun protection when going outdoors to prevent sunburn.
- Keep clothing soft. Use cotton fabrics that don’t irritate your skin.
- Use an electric razor rather than one with blades.
If you do get an injury, no matter how slight, make sure to treat it immediately. Wash gently with warm water and a gentle soap. Treating the injury immediately will cut the chances of it becoming infected. Once a skin injury becomes infected, the chances of developing psoriasis lesions increases. Contact your doctor if you see any sign of infection—including redness, swelling, or if the area feels warm to the touch.
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Updated on October 19, 2017
Eileen Bailey is a freelance health writer. She is the author of What Went Right: Reframe Your Thinking for a Happier Now, Idiot’s Guide to Adult ADHD, Idiot’s Guide to Cognitive Behavioral Therapy, Essential Guide to Overcoming Obsessive Love, and Essential Guide to Asperger’s Syndrome. She can be found on Twitter @eileenmbailey and on Facebook at eileenmbailey.