What Is Plaque Psoriasis? How Doctors Diagnose and Treat This Chronic Skin Condition


Being comfortable in your own skin takes on new meaning when it comes to living with plaque psoriasis.

“People often look at skin disease and think ‘Oh, it’s a rash; that’s not a big deal,’ but psoriasis is the poster child for how a skin disease is one piece of an overall systemic picture,” Adam Friedman, MD, professor of dermatology at George Washington School of Medicine and Health Sciences, tells Health. “The inflammation that causes psoriasis can affect organs and tissue in the body.”



Getty Images

More than 7.5 million Americans 20 years and older live with psoriasis, per a June 2021 JAMA Dermatology study. The National Psoriasis Foundation (NPF) reports that one in three people with psoriasis might also develop psoriatic arthritis, which causes swelling, stiffness, and pain in and around joints.

What is plaque psoriasis?

Plaque psoriasis is a skin condition that can appear as raised plaques and scales. It looks pink or silvery on lighter skin and purple or yellowish on darker skin, says Dr. Friedman.

The condition is associated with inflammation caused by immune system dysfunction, says the NPF. In other words, a person’s immune system overreacts to some genetic or environmental trigger, causing the inflamed, scaly patches we know as plaque psoriasis to appear.

Symptoms of psoriasis often begin between 15 and 25 years old, notes the NPF. However, people of any age can develop the condition.

What causes plaque psoriasis?

While it's not exactly known why some people get psoriasis and others don't, Dr. Friedman says the cause is believed to be a mix of nature and nurture.

“We know there is a genetic connection, but we don’t know enough about that yet, and we think there are certain triggers in the environment, so both [components] might release psoriasis,” he says.

Robert T. Brodell, MD, chair of the Department of Dermatology at the University of Mississippi Medical Center, says a phenomenon called Koebnerization (aka the Koebner effect)—named for a 19th century dermatologist—explains some instances of plaque psoriasis. It occurs where the skin has been traumatized. “So, if you have surgery for your appendix, you may heal from your surgery, but psoriasis may develop all along that scar,” he tells Health.

While scientists can't explain exactly why this might occur, they do know what's happening in the body when plaque psoriasis develops. Essentially, people with plaque psoriasis have an overactive immune system that causes skin cells to develop too quickly. Instead of growing and shedding over the course of a month, new cells appear in a matter of three to four days. But they don't fall off quickly; they pile up on the surface of the skin, creating a buildup of plaque and scales.

Psoriasis Causes, Plus 7 Things That Can Cause Symptom Flare-Ups. According to Dermatologists

How is plaque psoriasis diagnosed?

Plaque psoriasis is not your typical rash.

"There are various subtypes and forms that affect different locations of the body and depending on the location can come with its own impact on quality of life," says Dr. Friedman.

While a biopsy of the skin is often not needed for diagnosis of psoriasis, Dr. Brodell says sometimes a dermatologist may choose to perform a biopsy to exclude other possible conditions that also include scaling, such as cutaneous T-cell lymphoma.

To diagnose psoriasis, doctors often examine your skin and look for characteristics of psoriasis (scaly, raised plaques, etc.) on typical areas of the body where psoriasis occurs, such as the elbows, knees, and scalp.

"If people have scaly rashes in those areas, it is most likely psoriasis," says Dr. Brodell.

Because eczema can often be mistaken for psoriasis and vice versa, he says it's important that a dermatologist makes the diagnosis.

"For a dermatologist, looking at psoriasis and eczema is like the difference between a VW bug and a Porsche sports car. There are a lot of things about them that are the same, but we can detect some different things just looking at it," Dr. Brodell says.

Scalp Psoriasis Vs. Dandruff: How to Tell the Difference and What to Do to Relieve Your Scalp Itch

How is plaque psoriasis treated?

While there's no cure for psoriasis, Dr. Friedman says there are many treatment options that can clear up these skin lesions.

"The question isn't how are you going to treat psoriasis, it's which [treatment] are you going to pick because we have so many options," he says. And there are more and better treatments all the time. "We used to be happy clearing someone by 75%, but now we treat to clear it. We have drugs that will get you 99% clear."

Treatment options include:

  • Topical creams and ointments, such as steroid creams
  • Systemic treatments, meaning medications used to slow down the immune system
  • Biologic medications, or drugs that target areas and are not systemic
  • Phototherapy, which shines ultraviolet rays on the skin
  • Alternative options, such as salt baths and aloe vera

How to live with plaque psoriasis

Living with psoriasis can bring about discomfort, so seeking treatment from a qualified healthcare provider is the best way to find relief. However, living with psoriasis has social implications, too.

Facing stigma

According to a small, 2015 study in the Journal of the American Academy of Dermatology, psoriasis is just as stigmatized as herpes, with many study participants stating that they believed psoriasis to be infectious and contagious.

"It's a visual condition and when people see it, they might not understand it," says Dr. Friedman.

For instance, when people see someone with psoriasis on their scalp, if they might think their flaky, red scalp means the person is unkept or has a fungal infection.

"And so there is an added level of anxiety associated with that," Dr. Friedman notes.

Educating others about the condition is one way to help with the stigma and gain understanding from people in your life, such as family, coworkers, friends, and romantic partners.

6 Things That Can Make Psoriasis Better

Managing stress

Because nerve cells in the skin carry messages to the brain, Dr. Friedman says that when we are stressed, it affects the skin.

Stress can trigger psoriasis flares and even make your itching worse, says the NFP. And that’s why finding ways to manage stress is important for people with psoriasis. The NPF suggests trying these stress relievers:

  • Meditation
  • Exercise under the direction of a doctor
  • Seeking help from a mental health professional

To get more inspiring stories delivered to your inbox, sign up for the Healthy Living newsletter