What Is Psoriasis?

In This Article

Psoriasis is an autoimmune disorder that causes healthy skin cells to turn over at an abnormally fast rate, leading to cell buildup and flaking cells on the outermost layer of the skin that are seen as rashes or lesions. They can appear on virtually any part of the body.

The most common type is plaque psoriasis, but there are several others that cause lesions that are different from the patches of scales that are most familiar. Usually, psoriasis is easily diagnosed with a medical history and physical exam.

Psoriasis affects more than 6 million people in the United States, according to the Centers for Disease Control and Prevention (CDC). It's a chronic condition and can't be cured, but there are many effective ways to manage the symptoms, from simple measures like keeping skin moisturized to topical and oral medications and light therapy.

Types of Psoriasis
Verywell / Emily Roberts

Types of Psoriasis

The most common and familiar type of psoriasis is plaque psoriasis, but there are several others. While none can be cured, they can be managed with self-care, medications, and/or phototherapy.

The most common forms of psoriasis include:

  • Plaque psoriasis is characterized by periodic flares of well-defined, red patches of skin covered by silvery, flaky scales (plaques). The skin on extensor surfaces (areas on the opposite side of a joint, such as an elbow) are affected most often, but psoriasis plaques can form virtually anywhere, including the scalp and genitals.
  • Nail psoriasis is plaque psoriasis that affects the fingernails and toenails. Approximately 80 to 90 percent of people with plaque psoriasis have nail involvement, causing symptoms such as pitting, crumbling, salmon-colored areas called oil-drop patches, and more, depending on what part of the nail is affected.
  • Inverse psoriasis (intertriginous psoriasis) occurs in skin folds such as the armpits, beneath the breasts, and between the buttocks. Lesions are red and smooth rather than dry and scaly.
  • Guttate psoriasis usually is triggered by a viral or bacterial infection such as strep. It's characterized by pink teardrop-shaped bumps and is more common in children and people under age 30.
  • Pustular psoriasis produces lesions filled with non-contagious fluid made up of lymph fluid and white blood cells. Often, it's confined to small areas of the body, but there is a rare and very serious form of the condition called von Zumbusch psoriasis that affects larger areas of the body and is characterized by pus-filled blisters and red skin. Other symptoms include fever, chills, dehydration, and increased heart rate. People with von Zumbusch psoriasis often must be hospitalized as the condition can be fatal if not treated properly.
  • Erythrodermic psoriasis occurs when the entire body turns bright red and scaly. In this instance, a skin biopsy may be needed to distinguish erythrodermic psoriasis from other diseases. 

Psoriasis Symptoms

The most significant symptom of the various types of psoriasis is a distinctive rash—the thick, silvery scales of plaque psoriasis, the raindrop-shaped lesions of guttate psoriasis, the fluid-filled lesions of pustular psoriasis, and so on.

Other common symptoms shared by most types of psoriasis include discomfort in affected areas, especially pruritis (itching). Psoriasis also can cause symptoms that are specific to the body part involved. For example, when the fingernails or toenails are affected by plaque psoriasis, the nails develop dents on the surface (called pitting); in extreme cases, the nail actually might lift away from the nail bed.

Complications of psoriasis are also often specific to the part of the body that's affected and can range from inflammation of the middle of the eye to hearing issues to psoriatic arthritis.

Pictures of Psoriasis

This photo contains content that some people may find graphic or disturbing.

Psoriasis on a woman's skin
Psoriasis on a woman's skin.  

This photo contains content that some people may find graphic or disturbing.

Psoriasis on a man's elbow
Psoriasis on a man's elbow.

This photo contains content that some people may find graphic or disturbing.

Psoriasis on an elbow
Psoriasis on an elbow.

This photo contains content that some people may find graphic or disturbing.

Psoriasis on a leg
Psoriasis on a leg.  

This photo contains content that some people may find graphic or disturbing.

Psoriasis on an arm and torso
Psoriasis on an arm and torso.

Causes

As with any autoimmune disorder, the immune system in someone with psoriasis mistakenly attacks healthy tissue in the same way it would a real threat, such as a virus. Researchers believe this glitch in the immune system is passed along in genes, although having a genetic propensity for psoriasis doesn't guarantee that it will develop.

For an initial appearance of psoriasis to take place—and for subsequent outbreaks called flares to occur—other factors must be present. Common causes of psoriasis flares include infection, stress, temperature extremes, skin injury, smoking, and certain medications.

Diagnosis

Psoriasis causes distinctive changes in the appearance of the skin, hair, or nails. Usually, all it takes for a doctor to diagnose psoriasis is a medical history and a physical exam. Very rarely, a biopsy, in which a sample of skin is examined under a microscope, is necessary.

Psoriasis Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

If you develop a rash or changes on your scalp or nails, it can be helpful to have a general idea of what different types of psoriasis look like and also to have a sense of who it can sometimes mimic other skin conditions.

Treatment

Managing psoriasis usually requires a combination of treatments and self-care strategies.

Among the most-used types of products used for treating psoriasis are moisturizers; anti-itch medications (from oatmeal-based bath products to antihistamines); coal tar, which has been used for centuries to relieve inflammation; and medicated shampoos for scalp psoriasis.

Prescriptions commonly used for psoriasis include topical corticosteroids, immune-modulating drugs; topical retinoids; drugs derived from vitamin D; immune-modulating medications; and biologics—protein-based medications given by injection that work by blocking specific elements of the immune system.

Phototherapy is often prescribed for people with moderate to severe psoriasis. It involves exposing the body or specific body parts to ultraviolet light, which has a skin-calming, rash-relieving effect on the psoriatic skin.

Coping

Psoriasis can affect every aspect of a person's daily life. It can be embarrassing, interfere with daily life, and simply be a nuisance. Coping with psoriasis, then, involves tending to how symptoms impact you both physically and mentally.

Among others, strategies include dealing with cold temperatures and dry air that can trigger or exacerbate the condition; finding ways to cover up or camouflage skin lesions, if they are bothersome to you; and taking measures to get adequate sleep, since the discomfort of psoriasis often interferes with quality shut-eye.

It's important to know that people who deal with psoriasis are at an increased risk of depression and anxiety, as the condition can take a toll on a person's self-image, sex life, and more. Seeking support from a support group or therapist can be helpful.

A Word From Verywell

If you've just been diagnosed with psoriasis, you're likely feeling overwhelmed with the realities of your condition. It may be helpful to remember that although the condition isn't fully understood, it has been widely studied, resulting in a wealth of ways to successfully deal with it. If one treatment doesn't adequately control your symptoms, go back to your doctor, ask questions, and try something new. It may take trial-and-error, but you will be able to find a combination of treatments and coping strategies that will allow you to control your psoriasis and not the other way around.

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