Definition

Psoriatic arthritis is a joint problem (arthritis) that often occurs with a skin condition called psoriasis.

Alternative Names

Arthritis - psoriatic; Psoriasis - psoriatic arthritis; Spondyloarthritis - psoriatic arthritis; PsA

Causes

Psoriasis is a common skin problem that causes red patches on the skin. It is an ongoing (chronic) inflammatory condition. Psoriatic arthritis occurs in 7% to 42% of people with psoriasis. Nail psoriasis is linked to psoriatic arthritis.

In most cases, psoriasis comes before the arthritis. In a few people, the arthritis comes before the skin disease. However, having severe, wide-spread psoriasis appears to increase the chance of getting psoriatic arthritis.

The cause of psoriatic arthritis is not known. Genes, immune system, and environmental factors may play a role. It is likely that the skin and joint diseases have similar causes. However, they may not occur together.

Symptoms

The arthritis may be mild and involve only a few joints. The joints at the end of the fingers or toes may be more affected. Psoriatic arthritis most often causes arthritis only on one side of the body.

In some people, the disease may be severe and affect many joints, including the spine. Symptoms in the spine include stiffness and pain. They most often occur in the lower spine and sacrum.

Some people with psoriatic arthritis may have inflammation of the eyes.

Most of the time, people with psoriatic arthritis have the skin and nail changes of psoriasis. Often, the skin gets worse at the same time as the arthritis.

Tendons may become inflamed with psoriatic arthritis. Examples include the Achilles tendon, the plantar fascia, and the tendon sheath in the hand.

Exams and Tests

During a physical exam, the health care provider will look for:

• Joint swelling
• Skin patches, usually red and scaly (psoriasis)
• Pitting in the nails
• Joint tenderness
• Inflammation in the eyes

Joint x-rays may be done.

There are no specific blood tests for psoriatic arthritis or for psoriasis. Tests to rule out other types of arthritis may be done:

• Rheumatoid factor
• Anti-CCP antibodies

The provider may test for a gene called HLA-B27. People with involvement of the spine are more likely to have HLA-B27.

Treatment

Your provider may suggest nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce pain and swelling of the joints.

Arthritis that does not improve with NSAIDs may need to be treated with medicines called disease-modifying antirheumatic drugs (DMARDs). These include:

• Methotrexate
• Leflunomide
• Sulfasalazine

Apremilast is another medicine used for the treatment of psoriatic arthritis.

Multiple injectable biologic medicines are effective for progressive psoriatic arthritis that is not controlled with DMARDs. These medicines block a protein called tumor necrosis factor (TNF) or other proteins involved in the inflammation process. They are often helpful for both the skin disease and the joint disease of psoriatic arthritis.

Additionally, there is an oral synthetic agent, tofacitinib, that is available to treat psoriatic arthritis that is progressing even with the use of DMARDs or anti-TNF agents.

Very painful joints may be treated with steroid injections. These are used when only one or a few joints are involved. Most experts do not recommend oral corticosteroids for psoriatic arthritis. Their use may worsen psoriasis and interfere with the effect of other drugs.

In rare cases, surgery may be needed to repair or replace damaged joints.

People with inflammation of the eye should see an ophthalmologist.

Your provider may suggest a mix of rest and exercise. Physical therapy may help increase joint movement. You may also use heat and cold therapy.

Outlook (Prognosis)

The disease is sometimes mild and affects only a few joints. However, in many people with psoriatic arthritis damage to joints occurs within the first several years. In some people, very bad arthritis may cause deformities in the hands, feet, and spine.

Most people with psoriatic arthritis who do not improve with NSAIDs should see a rheumatologist, a specialist in arthritis, along with a dermatologist for the psoriasis.

Early treatment can ease pain and prevent joint damage, even in very bad cases.

When to Contact a Medical Professional

Contact your provider if you develop symptoms of arthritis along with psoriasis.

References

Fitzgerald O, Magee C. Psoriatic arthritis. In: Firestein GS, Budd RC, Gabriel SE, Koretzky GA, McInnes IB, O'Dell JR, eds. Firestein & Kelley's Textbook of Rheumatology. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 82.

Gossec L. Clinical features of psoriatic arthritis. In: Hochberg MC, Gravallese EM, Smolen JS, van der Heijde D, Weinblatt ME, Weisman MH, eds. Rheumatology. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 127.

Smolen JS, Schöls M, Braun J, et al. Treating axial spondyloarthritis and peripheral spondyloarthritis, especially psoriatic arthritis, to target: 2017 update of recommendations by an international task force. Ann Rheum Dis. 2018;77(1):3-17. PMID: 28684559 pubmed.ncbi.nlm.nih.gov/28684559/.

Veale DJ, Orr C. Management of psoriatic arthritis. In: Hochberg MC, Gravallese EM, Smolen JS, van der Hejjde D, Weinblatt ME, Weisman MH, eds. Rheumatology. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 131.