Dr. Fernandez explains that while we don’t know the exact cause of psoriasis, the prevailing belief is that people have a genetic predisposition to it. “When exposed to the appropriate outside trigger — a viral or bacterial infection, a significant life stressor, or environmental exposure — it sparks the initiation of that chronic inflammation,” says Fernandez. “Unfortunately, once it begins, we don’t have a permanent way to turn it off.”
What’s Going on With Your Skin When You Have Psoriasis
While the thick scales — combined with the sometimes-uncontrollable itchiness — make it very tempting to scratch and pick, Fernandez warns that this is not a good idea. To understand why, you’ll need to take a closer look at what’s happening with your skin. “Psoriasis triggers the cells within the upper layer of the skin, called the epidermis, to reproduce more rapidly than they would normally,” Fernandez explains. “That’s what leads to the visible rash.” In all people, as skin cells reproduce and move up toward the surface, they flatten out and form a thin layer of dead cells called the stratum corneum — the outermost layer of the skin — which has a protective function. For example, when bacteria and other organisms land on your skin and try to get inside your body, where they can cause infections, your skin sloughs off both the dead cells and foreign organisms as a defense mechanism. People with psoriasis have cells that reproduce much more rapidly than they should, so the outer layer of skin becomes especially thick, eventually forming a scale: a bunch of dead skin cells that formed so rapidly that they don’t slough off. The formation of the scale, combined with the itchiness, can tempt you to pick at the skin. That, in turn, can cause more psoriasis flares — something called the Koebner Phenomenon. “I see patients with psoriasis who are frustrated, because all of their clothes and bedsheets have blood on them,” says Fernandez. What’s more, the relief is short lived, he says. “That scale will re-form in a very short time.” Using a pumice stone as an exfoliant doesn’t work well, either. “Think of the skin as a simple organ whose job is to protect all of the organs that are living inside of the body,” Fernandez explains. “When you use things like a pumice stone to rub the skin, it thinks that something is trying to get underneath and do damage to the organs within, so it will respond to that trauma by getting thicker. Using a pumice stone causes far more damage than good.”
Ways to Treat Psoriasis
The best way to prevent scales from forming is by treating the psoriasis itself, he says. Here are a few treatments to try. Salicylic acid moisturizer People who have mild psoriasis may want to stick to topical treatments, including salicylic acid (which is in a class called keratinolytics), Fernandez says, which can safely and gently remove scales. Over-the-counter moisturizers with salicylic acid can help dissolve and decrease the thickness of scales on psoriatic lesions. Corticosteroid topicals Applying corticosteroids, another topical treatment, targets inflammation and itching and can help prevent you from scratching and exacerbating scales. Fernandez recommends putting on all topical medications after showering and lightly toweling off, because they tend to penetrate moist skin better. (Steroids have to penetrate that top layer of skin to reach the inflammation they’re targeting.) He also recommends reapplying in the evening before bed, when you’re no longer active. “If you put it on first thing in the morning, the medicine tends to rub off before it can penetrate,” he says. “When you have downtime, the medicine can stay on the skin much longer.” Phototherapy Light can be an effective way to control the inflammation and, as a result, decrease the amount of scaling. “Doctors don’t really know how it works, but the wavelengths of light will penetrate through the epidermis, and that light has immunosuppressive effects on the skin in the setting of an overactive immune system,” says Fernandez. He recommends getting five to 10 minutes of natural sunlight several times per week on areas that are affected by psoriasis to help control scaling and itching. Oral medication People with more widespread psoriasis may have systemic inflammation, says Fernandez. In this case, systemic medications, which come in the form of traditional medicines or newer biologic medications, may be able to help tamp down the inflammation. Avoiding triggers Lifestyle habits can trigger or aggravate psoriasis. Smoking; drinking alcohol; eating a high-calorie, high-fat diet; leading an inactive lifestyle; lacking sleep; and not managing stress have all been found to trigger psoriasis flares, he says.
