Merck Manual

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Psoriatic Arthritis


Kinanah Yaseen

, MD, Cleveland Clinic

Full review/revision Dec 2022
Topic Resources
  • Joint inflammation can develop in people who have psoriasis.

  • Joints commonly involved include the hips, knees, fingers, and toes.

  • The diagnosis is based on symptoms.

  • Nonsteroidal anti-inflammatory drugs, disease-modifying antirheumatic drugs (such as methotrexate), cyclosporine, and tumor necrosis factor inhibitors can help.

Psoriatic arthritis resembles rheumatoid arthritis Rheumatoid Arthritis (RA) Rheumatoid arthritis is an inflammatory arthritis in which joints, usually including those of the hands and feet, are inflamed, resulting in swelling, pain, and often destruction of joints.... read more Rheumatoid Arthritis (RA) but does not produce the antibodies characteristic of rheumatoid arthritis. Psoriatic arthritis occurs in about 30% of people with psoriasis Psoriasis Psoriasis is a chronic, recurring disease that causes one or more raised, red patches that have silvery scales and a distinct border between the patch and normal skin. A problem with the immune... read more Psoriasis (a skin condition causing flare-ups of red, scaly rashes and thickened, pitted nails). People with a certain gene (HLA-B27) and those who have affected family members are at increased risk of psoriatic arthritis of the spine. The cause of psoriatic arthritis is unknown.

Symptoms of Psoriatic Arthritis

In psoriatic arthritis, inflammation often affects joints closest to the tips of the fingers and toes, although other joints, including the hips, knees, and spine, are often affected as well. Often, the joints of the upper extremities are affected more. Back pain may be present.

The joints may become swollen and deformed when inflammation is chronic. Psoriatic arthritis affects joints asymmetrically (more on one side of the body than the other), more so than rheumatoid arthritis, and involves fewer joints. Tendons or ligaments can become inflamed where they attach to bone around the joints (called enthesitis). Some people who have psoriatic arthritis also have fibromyalgia Fibromyalgia Fibromyalgia is characterized by poor sleep, fatigue, mental cloudiness, and widespread aching and stiffness in soft tissues, including muscles, tendons, and ligaments. Poor sleep, stress, strains... read more , which causes muscle pain, joint stiffness, and fatigue.

The psoriasis rash may appear before or after arthritis develops. Sometimes the rash is not noticed because it is hidden in the scalp, navel, or creases of the skin such as between the back of the buttocks and thigh. The skin and joint symptoms sometimes appear and disappear together and sometimes they do not. Sometimes the skin symptoms are more severe than the joint symptoms, and sometimes the joint symptoms are more severe.

Psoriatic Arthritis

Diagnosis of Psoriatic Arthritis

  • Blood tests

  • X-rays

The diagnosis of psoriatic arthritis is made by identifying the characteristic joint inflammation in a person who has arthritis and psoriasis. Doctors also ask people whether they have a family history of psoriasis.

Prognosis for Psoriatic Arthritis

The prognosis for psoriatic arthritis is usually better than that for rheumatoid arthritis because fewer joints are affected. Nonetheless, the joints can be severely damaged.

Treatment of Psoriatic Arthritis

  • Disease-modifying antirheumatic drugs

  • Apremilast

  • Tumor necrosis factor inhibitors

  • Ustekinumab, secukinumab, ixekizumab, and abatacept

Apremilast, an effective medication taken by mouth used to treat psoriasis, may help treat arthritis.

Biologic agents are made from living organisms and inhibit certain chemicals involved in the immune system Overview of the Immune System The immune system is designed to defend the body against foreign or dangerous invaders. Such invaders include Microorganisms (commonly called germs, such as bacteria, viruses, and fungi) Parasites... read more . They include tumor necrosis factor (TNF) inhibitors Treatment Ankylosing spondylitis is a spondyloarthritis characterized by inflammation of the spine (spondylitis), large joints, and fingers and toes, resulting in stiffness and pain. Prolonged joint pain... read more Treatment given by injection or infusion (adalimumab, etanercept, infliximab, certolizumab pegol, golimumab, and guselkumab); ustekinumab, secukinumab, and ixekizumab given by injection; and abatacept given by injection or infusion. TNF inhibitors are particularly effective for psoriatic arthritis.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  • Arthritis Foundation: Information about psoriatic arthritis and available treatments, lifestyle tips, and other resources

Drugs Mentioned In This Article

Generic Name Select Brand Names
Otrexup, Rasuvo, RediTrex, Rheumatrex, Trexall, Xatmep
Cequa, Gengraf , Neoral, Restasis, Sandimmune, SangCya, Verkazia
Orencia, Orencia ClickJect
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