You’ve likely seen commercials about psoriasis, and you may know a friend or loved one who has it. Many people have heard of psoriasis but don’t know much more about it than it’s a skin condition.

Psoriasis is an autoimmune skin disorder that causes skin cells to multiply up to 10 times faster than usual. In the most common version of the disorder, it results in red patches with white scales.

“If it takes up about 3 percent or less of your skin’s surface, you have a mild case; between 3 and 10 percent is considered a moderate case, and 10 percent or above is severe,” said Geisinger dermatologist Paul Long, M.D.

While doctors don’t know precisely what causes psoriasis to flare up, they do know that your immune system and your genetics play a big part. About a third of people who develop psoriasis have a family member who has it, or had it at some point.

Psoriasis is most common among ages 15 to 35, although a breakout is possible at any age. Importantly, the condition is not contagious.

The knees, elbows and scalp are among the most common areas for a psoriasis breakout, but it could also affect areas of your torso, palms, lower back and the soles of your feet.

There are five different types of psoriasis. Plaque psoriasis, which is the most common, has the following symptoms:

  • Red bumps with white scales that cause itching and pain. If left untreated, these bumps can start to merge together and cover larger patches of skin.
  • Crumbling toenails or fingernails. You might also notice your nails detaching from the nail bed.
  • Rough patches on your head 

About 80 percent of people who have psoriasis have plaque psoriasis.

Another 10 percent of people who develop psoriasis suffer from guttate psoriasis, the second most common form of the disorder.

“It affects younger people and is typically triggered by an infection, such as strep throat, and causes spots similar to chicken pox,” said Dr. Long.

The three other major forms of psoriasis are inverse psoriasis, in which smooth red splotches appear on the backside of the knee, under the armpit or in the groin area; pustular psoriasis, in which white blisters of noninfectious pus are surrounded by patches of red skin; erythrodermic psoriasis, a rare but severe form of the disorder in which most of the skin is covered in redness, results when plaque psoriasis becomes unstable.

“Some of the triggers of psoriasis are cold and/or dry weather, stress, high blood pressure and heart disease medication, infections such as strep throat or tonsillitis, cuts, bruises, bug bites, new tattoos, drinking alcohol and using tobacco products,” said Dr. Long.

Additionally, psoriasis can sometimes lead to psoriatic arthritis. About 30 percent of people with psoriasis develop psoriatic arthritis, characterized by pain, stiffness and swelling in the joints.

While there isn’t a cure for psoriasis, medication can help alleviate and reduce symptoms. Natural remedies such as exposure to sunlight, aloe vera and dead sea salts could help keep psoriasis at bay. Laser treatments are becoming an increasingly popular option as well.

Using moisturizing lotion and a humidifier, especially when if the weather is cold and dry where you live, can help prevent psoriasis from flaring up, but consult a dermatologist to develop a treatment plan.