When your body's covered in the thick, dry, red patches that are the hallmark of plaque psoriasis, it's only natural that you may want to pinpoint exactly why you've developed them. Thing is, despite how common psoriasis is-it impacts nearly 1.6 million Australians-the causes aren't fully understood. (Though let's get one thing out of the way: psoriasis isn’t contagious, so you can't catch it by coming into contact with someone who has it.) But experts have some theories.
Your immune system likely plays a role
“It used to be thought of as a problem where the skin just produces ‘more scale’ and gets thicker than normal skin,” explains dermatologist Dr Jason Reichenberg. “Now we know this is caused by an overactive immune system.”
Translation: When you have psoriasis, your immune system goes a bit haywire, causing your white blood cells to attack the healthy tissues in your body. These signals cause your skin cells to grow faster than your body can shed them, and as a result, they pile up on the surface of your skin-commonly on your scalp, knees, elbows, buttocks, and lower back-resulting in scaly patches called plaques.
You can probably blame an out-of-whack immune system on your genes
Doctors aren’t sure why some people have these faulty immune systems and others don’t, says Dr Reichenberg, but genetics seems to be a driving force behind psoriasis. In a recent meta-analysis published in Nature Communications, researchers linked 16 genetic markers to psoriasis-bumping the genetic regions linked to the condition to 63-after analysing data from more than 39,000 people.
But not everyone who has the psoriasis gene actually develops the condition
Still, even if you have the genetic markers for psoriasis, you may never develop symptoms. Only 2 or 3 percent who have the right combo of genetic markers may actually develop the disease, according to the National Psoriasis Foundation. So even if your parents have psoriasis, that doesn’t necessarily mean you’ll get it, too, says Dr Reichenberg.
Researchers suspect that other factors besides genetics must cause psoriasis. For instance, people with psoriasis are also more likely to experience other serious diseases, like heart disease, obesity, diabetes, cancer, and even depression. It’s still unclear whether psoriasis could lead to those diseases or if those diseases could lead to psoriasis, according to preliminary research from the AAD.
Psoriasis triggers to know
There are also other day-to-day triggers that don’t necessarily cause psoriasis, but might make it worse or spark a flareup:
- Certain medications
- Dry skin
- Skin injury or sunburn
- Drinking a lot of alcohol
- Vitamin D deficiency
“About half of patients with psoriasis experience a flare in their disease with stress. It can be mental stress or a physical stressor,” says Dr Reichenberg. “Another common cause of flares is infections. We think that when a person’s body starts to get the immune system ready to fight an infection, it also makes the part of the immune system responsible for psoriasis get over active.”