Psoriasis can sometimes be likened to a moody teenager – it does what it wants and is completely unpredictable. And while most plaques actually don’t have a visible trigger and seem to happen randomly, there is an exception to this rule: the Koebner phenomenon.
Ouch! You just nipped your finger with a freshly sharpened kitchen knife that was supposed to slice a cucumber. The small cut, which is barely visible, is just as soon forgotten. But a few weeks later, a new plaque starts to form on your finger – would it ever have occurred to you that the cucumber cut was in fact the cause of it?
Your skin remembers
Heinrich Koebner, a well-known dermatologist from the 19th century1, first defined the condition, observing a connection between skin injuries and the emergence of new plaques2. It usually takes about 10-14 days after a skin injury for plaques to show up. But it can sometimes take as long as weeks, months or even years. The new plaques are no different to regular psoriasis plaques, and there’s nothing distinctive about them that would indicate a skin injury trigger.2
Scissors, knife, fork, light – what are the triggers?
You can have a Koebner response to anything that injurs your skin, altering it in some way on the outside or inside. This can include insect or animal bites, scrapes, cuts or burns.
You can also trigger the condition in less obvious and drastic ways like when3:
- the waistband of your tights digs into your skin
- you get sunburnt
- your glasses frame presses into your skin behind your ears
- you use hair dye with chemicals that irritate the skin
- you get a tattoo
- you shave or get wax treatment
Wrap yourself in cotton wool? How to avoid Koebnerisation
Of course, you’re never going to be able to prevent skin injuries altogether. It’s not like you can wrap yourself in cotton wool and avoid any kind of activity that could potentially hurt you.
The good news though is that many injuries can be avoided by taking small but effective measures. Some of these may seem obvious1:
- Avoid sunburn by applying sufficient sunscreen
- Use insect repellent spray (best to spray on clothing rather than directly on the skin)
- If tattoos aren’t an absolute must, maybe you can try and do without them
- Don’t wear tight tights or other garments with taut drawstrings
- Use hair dyes that don’t contain aggressive chemicals or, if possible, avoid hair dyes completely
It’s often just as easy to change some habits:
- To avoid day-to-day injuries caused by sharp edges, chemicals or while cleaning and gardening, you can often protect yourself by wearing gloves
- Use an electric razor instead of a manual razor with blades to prevent cuts
Keep cool — and start a diary
One thing is certain: the Koebner phenomenon is never going to be prevented entirely. Everyone incurs injuries from time to time, whether you burn yourself on hot saucepan or your cat scratches you because it’s having a bad day. But as long as you are aware of the injury, you can remain calm and just keep a close eye on it. If a new plaque emerges, here are the seven golden rules of psoriasis skincare that can help you. Keeping a psoriasis diary, for example, is a good way to record minor injuries or note down pressure points and other "incidents". Take good care of the injury and apply additional amounts of moisturiser once the wound has healed. And then all you can do is keep your fingers crossed! :-)