What Is Psoriasis? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Psoriasis is an autoimmune disease that causes plaques, which are itchy or sore patches of thick, dry, discolored skin.

While any part of your body can be affected, psoriasis plaques most often develop on the elbows, knees, scalp, back, palms, and feet.

Like other autoinflammatory diseases, psoriasis occurs when your immune system — which normally attacks infectious germs — begins to attack healthy cells instead.

Psoriasis plaques can range from a few spots of dandruff-like scaling to major eruptions that cover large areas. The disease’s symptoms and appearance vary according to the type and severity of psoriasis.

Some common signs and symptoms include:

• Discolored patches — classically, they’re red on fair skin and purple on dark skin — or raised plaques of skin that are covered with scales
• Dry or cracked skin that bleeds
• Burning, itching, or soreness near the affected areas
• Pitted or thickened fingernails or toenails
• Swollen joints (1)

Learn More About Psoriasis Symptoms

Psoriasis, in general, is a genetic condition passed down through families. “It’s likely that multiple genes need to be affected to allow psoriasis to occur and that it’s frequently triggered by an external event, such as an infection,” says James W. Swan, MD, a dermatologist who specializes in psoriasis at Loyola Medicine in Maywood, Illinois.

Certain risk factors, such as a family history or being obese, may increase your odds of developing psoriasis.

At least 10 percent of people inherit genes that could lead to psoriasis, but only 3 percent or less actually develop the disease. (2) For this reason, it is believed that the disease is caused by a combination of genetics and external factors or triggers.

A psoriasis outbreak may be provoked by:

Stress

Stress is a major trigger for some people with psoriasis, either causing psoriasis to flare up for the first time or to make it worse after you’ve been diagnosed. (3)

“Psoriasis is very stress-dependent. It flares very easily when patients are under stress, and it tends to improve when they’re relaxed,” says Vesna Petronic-Rosic, MD, a visiting professor at the University of Illinois Chicago and the director of dermatopathology at John H. Stroger, Jr. Hospital of Cook County in Chicago. Stress management techniques, such as exercise, yoga, and meditation, may help manage psoriasis symptoms.

Cold Weather 

A trip to the Caribbean might be a good idea during the winter months if you have psoriasis and live in a cold climate. That’s because the sun’s ultraviolet light turns off the skin’s immune system, which is overactive in people with psoriasis. Check with your dermatologist before traveling for sun safety skin tips and limit your daily exposure to no more than 10 minutes of direct sunlight.

Dry Skin 

Anything that injures the skin can cause a psoriasis flare, including excessively dry skin.

The solution: Keep your skin moisturized. If you’re allergic to the fragrances in moisturizers, use a product that’s fragrance-free to avoid a rash.

Vaccinations 

As with dry skin, puncturing the skin during a vaccination may cause a psoriasis flare, but that’s no reason to skip a needed shot. (4)

One thing to keep in mind: If you’re on a potent psoriasis medication that suppresses your immune system (such as a biologic treatment), you shouldn’t take a live vaccine. Your body may not be able to fight off a live virus because of the medication you’re taking. In that case, ask your doctor for a vaccine that contains a deactivated virus.

Beta-Blockers and Lithium 

Beta-blockers to treat high blood pressure and lithium for a mental disorder can make psoriasis worse. (5,6)

If you have high blood pressure, your doctor may be able to switch your medication to another drug that won’t affect the psoriasis. If you’re taking lithium, your dermatologist may consider having you try light therapy or a topical treatment for psoriasis.

Upper Respiratory Infections 

Colds and other infections, especially strep throat, activate the immune system and can cause psoriasis to flare. (7) If you have psoriasis and develop a sore throat, get it treated and be sure to have a culture taken to check for strep. Long-term antibiotics may be an option for someone who has psoriasis and frequent sore throats.

Smoking 

There’s some evidence that smoking can make psoriasis worse. According to a study, smokers have almost double the risk of developing psoriasis compared with people who’ve never smoked. (8) In a smaller study that looked at twins, heavy smokers were more than twice as likely to have psoriasis. (9)

Diet 

Studies haven’t shown any beneficial effects of taking nutritional supplements for psoriasis, but avoiding certain foods may reduce inflammation and help with psoriasis. Additionally, studies have shown that many people with psoriasis may also have a gluten sensitivity, and eating a gluten-free diet can help reduce psoriasis symptoms. (10)

It’s also best to eat nightshade vegetables — including eggplant, tomato, white potato, and peppers — in smaller quantities; they contain a chemical known to cause inflammation. In general, if you find that a certain food makes the psoriasis worse, try to avoid it.

Alcohol 

For some people with psoriasis, having more than one or two drinks a day has been shown to cause psoriasis flares, but the association is not a strong one. Flares from alcohol use could also be linked to psychological stress.

Learn More About Psoriasis Causes

There are five types of psoriasis, yet people most often have only one type of psoriasis at a time. Each type has its own set of symptoms.

Plaque Psoriasis

Also called psoriasis vulgaris, plaque psoriasis is the most common form of the skin disease. It appears as raised, discolored plaques covered with a scaly buildup of dead skin cells, or scales. The itchy, sometimes painful plaques can crack and bleed, and commonly affect the scalp, knees, elbows, back, hands, and feet.

Guttate Psoriasis

Often beginning in childhood or young adulthood, guttate psoriasis is the second most common type of psoriasis. Nearly 10 percent of people who get psoriasis develop guttate psoriasis. Guttate psoriasis is the type of psoriasis most closely linked to a recent strep infection. If you develop guttate psoriasis, you will also likely be tested for strep bacteria.

Inverse Psoriasis

Also known as intertriginous psoriasis, inverse psoriasis causes red or otherwise discolored lesions in skin folds of the body that may look smooth and shiny. Each lesion can occur on the genitals or in areas near the genitals, like the upper thighs and groin. It’s common for people with inverse psoriasis to have another type of psoriasis somewhere else on their body at the same time.

Pustular Psoriasis

This causes white blisters of pus that surround red or otherwise discolored skin, often on the hands or feet. The pus consists of white blood cells. When pus-filled bumps cover the body, you may have bright-red skin and feel ill or exhausted, and have a fever, chills, severe itching, rapid pulse, loss of appetite, or muscle weakness.

Erythrodermic Psoriasis

This is a dangerous and rare form of the skin disease characterized by a widespread, fiery redness or other discoloration and exfoliation of the skin that causes severe itching and pain. Erythrodermic psoriasis occurs once or more in 3 percent of people with psoriasis.

Learn More About the Types of Psoriasis

There aren’t any special tests to help doctors diagnose psoriasis. Typically, a dermatologist will examine your skin and ask about your family history.

You’ll likely be given a diagnosis based on this physical exam.

In some situations, doctors will remove a small sample of the skin and examine it under a microscope. This might allow them to get a better look at the affected area and make a more accurate diagnosis. (11)

Psoriasis is considered a chronic, lifelong condition. There currently isn’t a cure, and this skin disorder can worsen or improve.

For some, psoriasis can clear up for months or even years at a time. This is known as remission.

Others experience psoriasis flares in cyclical patterns. For instance, the disease may get better in the summer and worsen in the winter. (12) There are treatments that can keep your skin clear or nearly clear.

While psoriasis cannot be cured, there are effective options for treating it. Talk to your doctor about the benefits, risks, and side effects of any therapies you use.

Medication

Some medication to treat psoriasis includes:

• Topicals Prescription treatments, such as topical steroids, and over-the-counter (OTC) treatments that are applied directly to the skin can minimize symptoms of psoriasis. Each topical medication contains different active ingredients, such as salicylic acid, and can come as a lotion, cream, shampoo, gel, spray, or ointment. Topical corticosteroids are often prescribed for mild psoriasis or moderate psoriasis. The FDA recently approved two non-steroidal creams for psoriasis, as well: roflumilast (Zoryve) and tapinarof (Vtama).
• Biologics Biologic drugs are a type of systemic medication, which impact the entire body and alter the immune system. They are usually given as an injection, but some are available as a tablet. Biologics include etanercept (Enbrel), infliximab (Remicade), adalimumab (Humira), ustekinumab (Stelara), secukinumab (Cosentyx), ixekizumab (Taltz), brodalumab (Siliq), tildrakizumab (Ilumya), risankizumab (Skyrizi), guselkumab (Tremfya), and deucravactinib (Sotyktu).
• Apremilast (Otezla) This medicine comes as a pill and works by suppressing an enzyme that’s involved in inflammation.
• Oral Retinoids This type of systemic therapy is usually given if you have severe psoriasis that doesn’t respond to other treatments.
• Methotrexate (Rheumatrex) This drug helps control inflammation.  
• Cyclosporine (Gengraf or Neoral) This systemic treatment suppresses the immune system but can be taken for only short periods of time. (1)

Light Therapy

Light therapy, such as UVB phototherapy, involves exposing your skin to controlled amounts of natural or artificial ultraviolet light to help reduce symptoms of psoriasis. You may receive this treatment alone or along with other medication. (1)

Learn More About Psoriasis Treatment

There’s no way to prevent psoriasis, but there are things you can do to improve your symptoms and help lessen the number of flare-ups you experience. (13)

Some ways to reduce your risk of a psoriasis outbreak include:

• Take daily baths
• Keep skin moisturized
• Avoid triggers if you can
• Get a small amount of sunlight each day (1)

Having psoriasis can increase your risk for developing a number of health conditions, including:

• High blood pressure
• Obesity
• High cholesterol
• Diabetes
• Cardiovascular disease
• Osteoporosis
• Liver disease
• Kidney disease
• Cancer
• Uveitis (an eye disease)
• Crohn’s disease
• Depression (14)

“Over the past few years, we've seen that maybe psoriasis plays a more integral part in metabolic syndrome, a collection of symptoms that can lead to diabetes and heart disease,” says Erin Boh, MD, chairman and a professor of dermatology at the Tulane University School of Medicine in New Orleans.

It is estimated that up to 30 percent of people with psoriasis will also develop psoriatic arthritis, an autoimmune disease that affects the joints. Psoriasis occurs before joint disease in 85 percent of psoriatic arthritis patients. (15)

The risks for psoriasis-related complications are greater the younger a patient is when diagnosed and the more severe the psoriasis. (16) Anyone with psoriasis should be aware that they are at risk for comorbid conditions and should monitor their overall health accordingly.

Learn More About Psoriasis Complications

About 7.5 million people in the United States have psoriasis. Most are white, but the skin disease also affects Black, Latino, and Asian Americans as well as Native Americans and Pacific Islanders. (17)

The disease occurs about equally among men and women. It is more common in adults, and you are at a greater risk if someone in your family has it. (18) A study concluded that “interactions between particular genes as well as genetic and environmental factors play an important role” in the disease’s development. (19)

People with psoriasis generally see their first symptoms between ages 15 and 30, although developing the disease between 50 and 60 years of age is also common. (20)

“The biggest factor for determining prognosis is the amount of disease someone has,” says Michael P. Heffernan, MD, a dermatologist at the San Luis Dermatology & Laser Clinic in San Luis Obispo, California.

Many conditions are closely related to, and sometimes mistaken for, psoriasis.

Psoriasis and eczema may be tricky to tell apart.

If psoriasis affects your scalp, it might be hard to determine if it’s dandruff or psoriasis.

Other skin conditions like ringworm and pityriasis rosea are occasionally confused with psoriasis.

Is It Psoriasis or Eczema?

Like psoriasis, eczema is a very itchy skin condition. In fact, eczema usually results in a more intense itch than psoriasis. Scratching causes inflammation of the skin, leading to a worsening of the eczema. Scratching can also cause a secondary bacterial infection.

Eczema is not a specific disease, but rather a term referring to a group of rash-like conditions. The most common type of eczema is caused by a reaction to irritants, like detergents, soaps, or household cleansers.

Eczema often shows up on the back of the knees or the inside of the elbows.

Eczema can affect anyone and affects children more than psoriasis does. (21)

Is It Scalp Psoriasis or Dandruff?

More than half of all psoriasis patients have scalp psoriasis. (22) Itchy plaques can extend beyond the hairline onto the forehead, neck, and around the ears.

“Most people with scalp psoriasis have it on other parts of their body as well,” says Dina D. Strachan, MD, a dermatologist and assistant clinical professor of dermatology at NYU Langone Health in New York City.

Scalp psoriasis is sometimes confused with seborrheic dermatitis, or dandruff. According to Dr. Strachan, dandruff — which causes a flaky, itchy scalp without signs of inflammation — tends to itch more than scalp psoriasis. “It has a greasy-appearing yellow scale,” Strachan says. “In contrast, psoriasis — whether it's on your scalp or any other body part — tends to have a thick, silvery scale."

Learn More About Whether That Rash Is Psoriasis, Eczema, or Something Else

Learn More About Scalp Psoriasis

Psoriasis is less common in BIPOC (Black, Indigenous, and People of Color) populations compared with white ones, but it may be more severe and more challenging to diagnose.

According to research, psoriasis affects about 3.6 percent of Caucasians, as well 1.9 percent of African Americans and 1.6 percent of Hispanic Americans.

The appearance of psoriasis can differ depending on race and ethnicity. Psoriasis tends to be red or pink with silvery-white scale in white patients, while a Hispanic person is more likely to have salmon-colored psoriasis and silvery-white scale. In Black Americans, psoriasis often looks violet and the scale gray, or can be a deep brown and hard to see on people with very dark skin.

Psoriasis can be more severe for people of color than white people. A study found that Asians with psoriasis had the highest percentage of body surface area affected (41 percent), while Caucasians had the lowest (28 percent).

People of color who have psoriasis are less likely to get appropriate and timely treatment than their white counterparts. A study found that Black, Asian, and Native Americans are 40 percent less likely to see a dermatologist for their psoriasis than non-Hispanic white Americans, regardless of their health insurance or socioeconomic status.

One reason more people of color with psoriasis are not receiving high-quality treatment may be systemic racism in the medical field and the health disparities it causes. An analysis of dermatology textbooks showed that the number of images of skin of color ranged from 4 to 18 percent, with many textbooks showing zero images of skin of color with psoriasis. 

Favorite Organizations for Essential Psoriasis Information

American Academy of Dermatology

The AAD represents the vast majority of practicing dermatologists in the United States. Its website includes a tool that allows you to search its database to find dermatologists in your area.

American College of Rheumatology

This global organization of physicians, health professionals, and scientists has provided a comprehensive website that offers a wealth of patient and caregiver resources, including educational videos, information on available medication and therapies, and a search tool to find a local rheumatologist.

National Institute of Arthritis and Musculoskeletal and Skin Diseases

Dedicated to supporting research to treat diseases affecting muscles, bones, joints, and skin, NIAMS offers a website that provides an exhaustive guide to skin conditions and related topics, as well as news on the most recent clinical trials.

National Psoriasis Foundation

As the leading patient advocacy group for people living with psoriatic disease, the NPF provides an enormous online support community for people dealing with psoriasis. It provides a wealth of patient resources, including personalized guidance on how to deal with the disease.

The Psoriasis and Psoriatic Arthritis Alliance

Founded in 2007, this alliance of two former psoriasis-based foundations operates a website offering information, advice, and support for those living with psoriasis, including a special section for children coping with the disease.

Psoriasis Cure Now

This patient advocacy group specializes in raising awareness about the seriousness of psoriasis and the need for additional medical research. It also provides resources and information to encourage patients to advocate for themselves when seeking medical care.

The Skin of Color Society

This nonprofit works to increase awareness of dermatological issues as they impact the BIPOC community, working to educate physicians and the general public. A “Find a Doctor” database helps people with skin of color — including Black Americans, Asians, Hispanics or Latinos, Native Americans, and Pacific Islanders — connect with a clinician who is right for them.

Favorite Sites for Financial Assistance and Advocacy

National Psoriasis Foundation — Advocacy

NPF Advocacy helps organize volunteers to share information and advocate with legislators for change in public policy regarding psoriasis.

NeedyMeds

This online nonprofit information resource helps users to find programs that help patients who can’t afford medication and healthcare costs.

Favorite Blogs

The Itch to Beat Psoriasis

Everyday Health contributor Howard Chang provides a firsthand perspective on psoriasis with an extra dose of encouragement, education, and empathy. Chang’s posts deal with the everyday details of living with psoriasis, including topics such as navigating the condition as a parent and how best to use the frequent time you spend in doctors’ waiting rooms.

Just a Girl With Spots

Having been diagnosed with psoriasis at 15, blogger Joni Kazantzis writes about not only her personal battles with the condition but also the mental and physical challenges that each person with psoriasis must battle daily.

Overcoming Psoriasis

Todd Bello was diagnosed with psoriasis at age 28. Through his blog, Bello shares regular posts about living with psoriasis as well as his patient advocacy efforts as a very active volunteer for the NPF. His passionate efforts on behalf of others with psoriasis have helped build a community of support for those dealing with the condition.

National Psoriasis Foundation Advance Online

With the motto “The P is silent but we are not!” this blog is a frequently updated resource that covers a wide spectrum of psoriasis-related topics, including health, advocacy, and inspirational personal stories.

Favorite Retreats

Soap Lake Natural Spa and Resort

Soap Lake in Washington state has long been a popular destination for those dealing with skin conditions, thanks to the lake’s high natural mineral count and alkaline levels. In addition to specialized treatments, the Soap Lake Natural Resort and Spa also provides healthy dining options and a number of outdoor activities. Its accommodations also include in-room Jacuzzis that use water pumped from the lake, allowing you to experience the lake’s waters from the privacy of your room at any time during the year.

Blue Lagoon

Set in a volcanic Icelandic landscape, the Blue Lagoon resort provides luxury accommodations and fine dining, complete with a private lagoon at the Silica Hotel. Its best feature, however, may be the clinic, which is widely popular in treating psoriasis. Guests can bathe in the mineral-rich seawater of the lagoon, while other treatments include UV light therapy and a host of internally developed skin-care products.

Favorite Apps

Flaym

Created by the LEO Innovation Lab, this user-friendly app is a social media platform for people living with psoriasis. In addition to providing an easier way to connect with others dealing with the condition, it provides groups based on topic (parenting, diet, exercise, travel) and offers tools to help host meetups.