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Disease Summary

Psoriasis is an autoimmune-related skin disorder characterized by immune-related overproduction of skin cells, causing them to pile up on the skin resulting in areas of thickened, inflamed, red skin, often covered with silvery scales (referred to as plaques). It is the most prevalent autoimmune disease in the U.S. and approximately 2 percent of the world population is affected. According to current studies, as many as 7.5 million Americans have psoriasis. Severity of the disease can also range from mild to severe according to the proportion of skin affected, joints affected, and how the disease affects quality of life. Some people with psoriasis also get a related form of arthritis called psoriatic arthritis, which produces joint pain, swelling, and stiffness, as well as psoriasis-related skin symptoms. While exact cause of the disorder is unknown, it is believed that the disease develops due to a combination of immune, genetic, and environmental factors. Psoriasis and psoriatic arthritis are usually lifelong conditions and although not currently curable, many treatments are available that can reduce bothersome symptoms and appearance of the disease.

Types of Psoriasis and Psoriatic Arthritis

There are five classifications of psoriasis with varied symptoms:

Plaque psoriasis
is the most common form of psoriasis and is characterized by red patches of skin covered with silvery scales.

Guttate psoriasis (GUH-tate)
appears as small salmon-pink dot-like lesions on the skin.

Pustular psoriasis
white blisters surrounded by red skin and intense scaling. There are three different forms of pustular psoriasis.

Inverse psoriasis
is characterized by severe inflammation and is found mostly in axillary areas like under arms, groin, under breasts and in other skin folds around buttocks and genitals.

Erythrodermic psoriasis (eh-REETH-ro-der-mik)
appears as intense itching and redness of the skin.

Additionally, there are five different classifications of psoriatic arthritis, each with similar yet distinctive symptoms:

occurs on same joints on both sides of body and can be disabling.

can involve a few or many joints anywhere on the body and is usually mild in form.

Distal interphalangeal predominant (DIP)
usually affects the joints closest to the nails on the fingers and toes.

inflammation of the spinal column causing stiff neck and lower back pain.

Arthritis mutilans
severe, deforming and destructive condition of the hands and feet that affects fewer than 5% of people with psoriatic arthritis.


No special blood tests or diagnostic tools exist to diagnose psoriasis. Dermatologists (skin specialist) usually examine the affected skin to make a diagnosis. Sometimes they may examine a piece of skin (biopsy) under a microscope. A complete medical history, physical exam, blood tests, MRI’s and x-rays of the joints that have symptoms are used to diagnose psoriatic arthritis.

Common Symptoms of Psoriasis

Symptoms of psoriasis include dry areas of thickened, inflamed, red skin, often covered with silvery scales. Patients may also experience itching, skin pain, and discolored or crumbly nails. Symptoms most often occur on the scalp, knees, elbows, torso, hands, and feet, but can develop anywhere.

Common Symptoms of Psoriatic Arthritis

Major symptoms of psoriatic arthritis include pain, morning stiffness and fatigue as well as swelling in and around joints. Mostly hands and feet are affected although symptoms can occur in elbows, knees and back. Symptoms commonly develop between the ages of 30 and 50. Early recognition, diagnosis and treatment can help prevent or limit extensive joint damage that occurs in later stages of the disease. Psoriatic arthritis may develop slowly with mild symptoms, or it could develop quickly and be more severe. Your doctor should be informed immediately if you experience any of these symptoms.

Risk for Comorbid Conditions

Individuals with psoriasis or psoriatic arthritis are at an increased risk to develop other chronic and serious health conditions also known as comorbid disease. These include heart disease, inflammatory bowel disease, diabetes, and depression. It is recommended to discuss these risks with a health care professional.