Psoriasis: Symptoms, Causes, & Treatment

By Gila Lyons
Medically reviewed checkmarkMedically reviewed
January 5, 2020

According to the National Psoriasis Foundation, about 2-3% of the world’s population has psoriasis. That’s more than 125 million people globally. In the U.S., it’s closer to 2%, which numbers 8 million Americans. While the exact cause of psoriasis is unknown, some combination of genetics, immune system functioning, and outside triggers causes skin cells to grow about five times faster than they usually would.

The extra skin cells don’t slough off, but instead form scales or red patches that can itch, hurt, crack, and bleed. The body parts most commonly affected by psoriasis are elbows, knees, and scalp, but rashes can appear anywhere.

There is no cure for psoriasis, and the disease can cause additional health complications, but you can manage symptoms through medications and lifestyle changes. In this brief, we’ll show you how.

Check your symptoms and get personalized health answers for free

Get started

What Is Psoriasis

Psoriasis is a chronic skin condition that usually appears in early adulthood. It’s thought that an overactive immune system causes skin cells to grow faster than usual, causing skin to itch, hurt, become inflamed, flake and sometimes crack and bleed.

Normally, skin cells slough off and are replaced every 10-30 days, but in those with psoriasis, new cells grow every 3-4 days, causing a buildup of old cells along with new ones. For most people, only certain areas are affected, like the folds of their skin, or hands and feet. But in more severe cases psoriasis can cover large parts of the body.

Psoriasis is not contagious and can be treated with steroid creams, special bandages, light therapy and oral medications. Psoriasis affects men and women at about the same rate, and it affects Caucasians (3.6%) almost twice as often as it affects African-Americans (1.9%). It usually develops between the ages of 15-35, but it can develop at any age.

Psoriasis Symptoms

Psoriasis symptoms vary from person to person. People can also experience psoriasis differently depending on where it is on their body. For example, the skin can react differently whether psoriasis appears on the eyelids, mouth, hands, or feet.

Most psoriasis cyclically flares and subsides, with weeks or months on, and months or even years off. While there is a range of symptoms, common symptoms include:

  • Red skin covered with thick, white or silvery scales
  • Dry and cracked skin
  • Skin that itches, burns, or stings
  • Thickened, pitted, or ridged fingernails
  • Nails that are yellowish, or that loosen and separate from the nail bed (onycholysis)
  • Swollen and stiff joints

Types of Psoriasis

There are five different types of psoriasis, and symptoms can depend on which type you have.

  • Plaque psoriasis: Plaque psoriasis is the most common type, and appears as raised, red patches of skin covered with whitish scales, which are buildups of dead skin cells. These patches can be itchy and painful, and can sometimes crack and bleed.
  • Guttate psoriasis: Guttate psoriasis is the second most common type of psoriasis, and often appears in childhood or young adulthood. It causes small, red spots to appear, mostly on the torso and limbs. This type of psoriasis may be triggered by infections like strep throat and tonsillitis, stress, injury to the skin, or taking certain medications.
  • Pustular psoriasis: This type of psoriasis causes red, scaly skin with small blisters, or pustules on it, most often occurring on the palms of the hands and soles of the feet. The blisters contain pus made of white blood cells. While pus usually signifies infection, pustular psoriasis is not an infection, and it is not contagious.
  • Inverse psoriasis: Inverse psoriasis causes bright red shiny rashes in places where the skin folds, like the armpits, groin, behind the knee and under the breasts. Many with inverse psoriasis also have other types of psoriasis elsewhere on their bodies.
  • Erythrodermic psoriasis: This is a rare type of psoriasis, occurring in just 3% of those with psoriasis. This type of psoriasis is distinctive in that it can cause bright redness all over the body, severe itching and pain, and skin to fall off in sheets. It can be triggered by severe sunburn, infections, and certain medications, and should be treated as a medical emergency as it can lead to serious illness.

Common Causes of Psoriasis and Psoriasis Triggers

Scientists haven’t been able to pinpoint the exact genes or immune system disorders that cause psoriasis, but they do know that both the immune system and genetics contribute greatly to its development. It is thought that in those with psoriasis, the genes that control the immune system create inflammation, which puts skin cells on overdrive, causing a buildup.

Scientists have found about 25 genes that are different in people with psoriasis. However, not everyone with a genetic predisposition towards psoriasis will develop it. Often, in those who develop psoriasis, something triggers it to appear. Common triggers are:

  • Injury to the skin such as cuts, scrapes, severe sunburn, or surgery
  • Infections such as strep throat, tonsillitis, bronchitis, and skin infections
  • Stress
  • Certain medications like beta-blockers and other blood pressure medications, lithium, antimalarial drugs, and iodides
  • Excessive smoking or alcohol consumption
  • Severe vitamin D deficiency
  • Hormonal changes like those during puberty, pregnancy, postpartum, and menopause
  • Cold, dry weather
  • Obesity can worsen psoriasis in skin creases and folds

While anyone can develop psoriasis, some people are at increased risk. These include those with:

  • Family history of psoriasis
  • Viral and bacterial infections like those with HIV, or other recurring infections
  • Chronic stress
  • Obesity
  • High consumption of alcohol
  • Heavy smoking habits

How Is Psoriasis Diagnosed?

There aren’t any blood tests to diagnose psoriasis, but a health care provider or dermatologist can usually diagnose psoriasis quite easily through three methods:

  • Physical exam: A health care provider will look at your skin, scalp, and nails.
  • Skin biopsy: Rarely, your health care provider may take a sample of affected skin to examine under the microscope.
  • Taking a family history: About a third of people with psoriasis have a family member with it, and it can sometimes jump a generation. For example, your grandfather may have psoriasis, then it can skip your parents, but you might have it. Knowing your family history can help inform the physical exam and biopsy.

Psoriasis Treatment Options

There are a variety of methods for treating psoriasis, and types of treatments can depend on whether your psoriasis is:

  • Mild: Psoriasis covers less than 3% of your body.
  • Moderate: Psoriasis covers 3-10% of your body.
  • Severe: Psoriasis covers more than 10% of your body.

Treatments for mild psoriasis

Mild psoriasis is often treated with topical treatments, like moisturizers, steroid creams, and shampoos.

Treatments for moderate to severe psoriasis

Moderate to severe psoriasis often requires a treatment that incorporates various strategies. In addition to topical treatments, your doctor may prescribe light therapy (phototherapy to slow the growth of skin cells), or medications that are injected or taken by mouth.

What You Can Do at Home

Unfortunately, you can’t prevent psoriasis from developing, but you can make certain lifestyle changes to avoid triggering it, or to ease a flare up.

Diet is one controllable factor that can have an impact on psoriasis. Following a diet that incorporates some or all of the following tips can help support your immune system and ease psoriasis symptoms.

Try to eat more:

  • Dark leafy greens: The antioxidants in dark leafy green vegetables can help protect against inflammation. The vitamin C and iron they contain can also boost your immune system.
  • Fatty fish: The omega-3 fats can help guard against inflammation as well as give your immune system a boost. Eating fatty fish like salmon, albacore tuna, mackerel, sardines, and herring at least twice a week has been shown to improve psoriasis symptoms for some.
  • Whole grains: Foods rich in fiber like whole grains can ease inflammation.
  • Olive oil: Like fish, olive oil has anti-inflammatory omega-3s. Avocados and many nuts also have omega-3s, so if you don’t like olive oil, you have options!
  • Fruit: The fiber, antioxidants, and vitamins in fruit can help fight inflammation. Berries, cherries, and apples have antioxidants called polyphenols that might be particularly helpful to those with psoriasis, and pineapple contains the anti-inflammatory enzyme bromelain.
  • Beans: Containing protein, fiber, and antioxidants, beans can help you fight inflammation while avoiding red meat, which some studies have shown can aggravate psoriasis symptoms.

To help ease psoriasis symptoms, try to eat less:

  • Fatty red meat: The saturated fat in red meat can trigger inflammation and lead to more frequent or severe psoriasis flare ups. Eating a lot of red meat can also increase your risk of heart disease, and people with psoriasis are at increased risk of heart attack and stroke. Lean meats and ground meats with the lowest percentage of fat are good choices for meat cravings.
  • Sugar: Sugar can also increase inflammation and increase your risk of heart disease. It’s also one of the biggest causes of obesity, which can worsen psoriasis symptoms.
  • Fried foods: Like with fatty red meats, the high saturated fat content of deep or heavily fried food can increase inflammation, leading to psoriasis flare ups.
  • Alcohol: Scientists don’t understand why, but alcohol has been shown to worsen psoriasis. Perhaps it is because it weakens the immune system and can cause inflammation. Alcohol can also interfere with optimal functioning of some psoriasis medications.

In addition to diet, some alternative therapies have been shown to ease psoriasis symptoms, especially for those with milder cases of psoriasis. Plaque psoriasis seems to be responsive to many of the home remedies below. It’s a good idea to consult with a health care provider before beginning home remedies, which include:

  • Aloe vera: Gel or cream from this plant can reduce inflammation, redness, scaling, and itching.
  • Fish oil supplements: If regularly eating fish that contains omega-3 fatty acids proves difficult, you can try taking a fish oil supplement in the form of a capsule. It can help prevent inflammation and protect your heart.
  • Oregon grape (barberry): Using Oregon grape topically may help reduce inflammation and ease psoriasis symptoms.
  • Warm baths with oatmeal, Epsom salt, Dead Sea salt, or soothing oils: Daily bathing can help remove the build-up of skin cells. It can also calm inflamed skin. However, make sure the water isn’t too hot, and that you’re not using harsh chemical soaps – both can worsen psoriasis symptoms. After soaking for about 10 minutes, gently pat your dry skin.
  • Moisturize: Soothe your skin with moisturizing creams and oils, either prescription or over-the-counter. Your dermatologist should have good suggestions for what to use.
  • Mild sun exposure: Small and gentle amounts of sunlight can improve psoriasis. However, too much time in the sun or sun intensity can trigger an outbreak or worsen symptoms, so go slow and gentle, and stay protected from the sun during the heat of the day.

Generally speaking, learning about psoriasis, and about what your specific triggers are, can empower you to make decisions about your lifestyle and treatment options.

Psoriasis support groups

Many with psoriasis can experience low self-esteem or depression. If you feel an emotional impact from psoriasis, look for a local support group or join one online. Sharing your experience with others and meeting people who face challenges like yours can be healing and enlivening.

Check your symptoms and get personalized health answers for free

Get started

Having psoriasis puts people at greater risk of developing certain diseases. It’s good to know what these are, as early detection increases the effectiveness of treatment. These include:

  • Psoriatic arthritis: Psoriatic arthritis (PsA) is an inflammatory form of arthritis, that can cause pain, swelling, stiffness in, and damage to the joints. According to The National Psoriasis Foundation, between 10-30% of people with psoriasis develop psoriatic arthritis. People with psoriatic disease are also at greater risk for developing certain conditions, like cardiovascular disease and depression. PsA can start at any age, but it commonly appears in people between the ages of 30-50, and often about 10 years after onset of psoriasis symptoms. Unfortunately, there isn’t a cure for PsA, but there are a variety of treatments that slow the progression of the disease, lessen pain, and protect joints to preserve range of motion. If you suspect you have psoriatic arthritis, consult with a rheumatologist (arthritis doctor), as untreated PsA can permanently damage joints.
  • Eye infections: People with psoriasis are at greater risk for developing eye infections like conjunctivitis, blepharitis and uveitis.
  • Type 2 diabetes: People with psoriasis are at greater risk for developing type 2 diabetes. Possibly because of increased inflammation, people with psoriasis are often also prone to obesity, which can be another risk factor for type 2 diabetes.
  • High blood pressure: Having severe psoriasis can increase your risk of having uncontrolled high blood pressure.
  • Cardiovascular disease: People with psoriasis may have twice the risk of cardiovascular disease as those without it.
  • Autoimmune disease: People with psoriasis are more likely to develop other autoimmune disorders, like celiac disease, sclerosis, and Crohn’s disease, and ulcerative colitis.
  • Kidney disease: People with severe psoriasis are twice as likely to develop chronic kidney disease than those with mild or no psoriasis.
  • Osteoporosis: One study showed that 60% of psoriasis patients had osteopenia, an early form of osteoporosis, and 18% had developed osteoporosis.
  • Emotional disruptions: People with psoriasis can be affected with low self-esteem and depression because of the social impacts of the disease, and the self-consciousness some develop in response to outbreaks.
  • Cancer: People with psoriasis have an increased risk for certain types of cancer, like lymphoma and nonmelanoma skin cancer.
  • Liver Disease: People with psoriasis and psoriatic arthritis may be at greater risk for nonalcoholic fatty liver disease (NAFLD).

When to See a Doctor

Make an appointment with your doctor if you have a rash that lasts longer than a week, or one that doesn’t improve with over-the-counter medication. Other reasons to be evaluated by your doctor for psoriasis include:

  • Painful or itchy rashes that are scaly, flakey, or peel
  • Rashes that interfere with your daily life because of appearance, itchiness, or pain
  • Swelling, stiffness, or pain in your joints
  • You have a family history of psoriasis and suspect that you might as well
  • You are diagnosed with psoriasis, but your current treatments aren’t providing enough relief

Check your symptoms and get personalized health answers for free

Get started

How K Health Can Help

Get Answers, Fast.

Did you know you can get affordable primary care with the K Health app?

Download K Health to check your symptoms, explore conditions and treatments, and if needed text with a clinician in minutes. K Health’s AI-powered app is based on 20 years of clinical data.

Do you think you might have psoriasis?

Download the K Health app.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Gila Lyons

Gila Lyons' health writing has appeared in The New York Times, Oprah Magazine, Vice, Cosmopolitan, Health Magazine, Healthline, and other publications. Connect with her at