Up to 30 percent of people with psoriasis may also develop psoriatic arthritis (PsA), a condition that causes pain and inflammation in and around the joints—most often in the fingers or toes. Healthcare providers don’t know what causes psoriatic arthritis, but experiencing an injury may increase the risk.
A large study from researchers in Iceland and at Harvard found that people with psoriasis were more likely to develop psoriatic arthritis if they experienced physical trauma (particularly in a bone or joint).
The researchers analyzed medical records of more than 70,000 people with psoriasis between 1995 and 2003. Of those, 15,416 patients were exposed to trauma, either involving the skin, nerves, bones, or joints. According to the analysis, people who suffered a bone injury were 46 percent more likely to develop PsA than those who did not. Those with a joint injury had a 50 percent higher risk. Skin or nerve trauma, on the other hand, didn’t appear to be connected with PsA.
The connection between physical trauma and psoriatic disease isn’t new. Dermatologists have long known that a skin injury (like a scrape or sunburn) can trigger a new patch of psoriasis. They even have a name for it—the Koebner phenomenon. Experts have suggested that the same thing may happen to the joints after an injury. The theory is that the immune system overreacts to the injury, leading to skin symptoms or joint symptoms.
Obviously, you can’t completely protect yourself from an injury. But, if you have psoriasis, you may be able to modify your risk of psoriatic arthritis by taking steps to avoid injuries. Protecting your skin—for example, by wearing sunscreen to protect from sunburn—should also be a part of your treatment plan for psoriasis.
