An Overview of Psoriatic Arthritis

Psoriatic arthritis is an inflammatory type of arthritis associated with psoriasis (a skin condition) and chronic joint symptoms. The symptoms of psoriasis and joint inflammation often develop separately. In 85 percent of people with the disease, symptoms of psoriasis precede arthritis symptoms. Arthritis develops before psoriasis in up to 15 percent of those with psoriatic arthritis.

A look at psoriatic arthritis along the fingers and forearm.

According to the CDC, about 6.7 million adults in the United States have psoriasis. In people with psoriasis, about 15 percent develop psoriatic arthritis. Its exact prevalence is not known, but it has been estimated to be between 0.3 percent to 1 percent of the population. The age of onset of psoriatic arthritis is usually between 30 and 50 years of age, but it can develop at any age. Men and women are equally affected.

Symptoms Associated With Psoriatic Arthritis

Symptoms associated with psoriatic arthritis vary in how they occur and which joints are affected. Any joint in the body can be affected with pain and tenderness. There may be stiffness and difficulty moving the affected joints through their normal range of motion. Some people with the disease experience morning stiffness that lasts more than a half hour. When psoriasis is involved, there are patches of red, patchy, raised, or scaly areas of skin. Nail abnormalities may appear as pitting and thickened or discolored fingernails. Other common symptoms associated with psoriatic arthritis include fatigue, swollen sausage-shaped fingers and toes (dactylitis), tendinitis, enthesitis, low back pain, and conjunctivitis.

Types of Psoriatic Arthritis

Psoriatic arthritis belongs to a group of conditions known as spondyloarthropathies. There are five recognized types of psoriatic arthritis which are differentiated by their symptoms. The five types, which can overlap, are:

  • Symmetric Psoriatic Arthritis affects joints on both sides of the body (e.g., both knees, both hips), and usually affects multiple joints (polyarthritis). It is similar to rheumatoid arthritis but is typically milder with less deformity. About 25 percent of psoriatic arthritis patients have this type of the disease.
  • Asymmetric Psoriatic Arthritis does not affect the same joints on both sides of the body. Any joint can be affected, though. Sausage-like appearance of fingers and toes is common. Joints may be red, warm, swollen, and painful. Generally considered a mild form of psoriatic arthritis, it may become disabling in some people. About 80 percent of people with psoriatic arthritis are affected by this type of the disease.
  • Distal Interphalangeal Predominant (DIP) Psoriatic Arthritis is considered the "classic type," according to the National Psoriasis Foundation, although it occurs in only about 5 to 10 percent of those with psoriatic arthritis. The primary features of this type of psoriatic arthritis are the involvement of the distal joints of the fingers and toes (the joint closest to the nail), as well as evidence of nail changes.
  • Spondylitis Type of Psoriatic Arthritis has inflammation of the spine as the primary symptom. About 5 to 20 percent of people with psoriatic arthritis are affected with the spondylitis type. About half of those with spondylitis are positive for HLA-B27, a genetic marker.
  • Arthritis Mutilans Type of Psoriatic Arthritis is considered severe, disabling, and rare. Less than 5 percent of people with psoriatic arthritis are affected. Joint deformity characterizes arthritis mutilans with the small joints of the hands and feet most affected. Neck pain and low back pain are also associated with this type of psoriatic arthritis.

Diagnosis of Psoriatic Arthritis

There is no single test used to diagnose psoriatic arthritis. A physical examination, x-rays, and MRI are used to help formulate the diagnosis. Blood tests are mostly used to rule out other types of arthritis with similar symptoms, such as rheumatoid arthritis, gout, reactive arthritis, ankylosing spondylitis, and osteoarthritis.

While some aspects of psoriatic arthritis are similar to other types of arthritis, the skin lesions, nail abnormalities, and patterns of inflammation differentiate it from other inflammatory types of arthritis. As soon as the diagnosis is confirmed by a doctor, appropriate treatment can begin. Early diagnosis and early treatment are important to bring the disease under control, providing the best chance to prevent disability, disease progression, and permanent joint damage.

Treatment of Psoriatic Arthritis

Because psoriatic arthritis involves both skin manifestations and joint manifestations, the target of any treatment plan must have that dual focus. Your rheumatologist will consider disease severity when choosing a treatment, as well as consider the potential effect of a particular treatment on other aspects of the disease. For example, will a medication chosen to manage arthritis symptoms help or hurt the skin aspects of psoriatic arthritis? Comorbidities are also a factor in selecting a treatment.

Usually, NSAIDs (nonsteroidal anti-inflammatory drugs) are the first-line medication for people with mild peripheral arthritis symptoms. For people with moderate to severe arthritis symptoms, who do not respond well to NSAIDs alone, DMARDs (disease-modifying anti-rheumatic drugs), such as methotrexate or Arava (leflunomide), may be used. Biologic drugs, such as TNF blockers, are appropriate for people with severe disease (e.g., evidence of erosions, several joints affected, considerable functional limitation). Corticosteroids are typically not used for psoriatic arthritis.

When skin symptoms are prominent, perhaps equally severe as joint symptoms, medications that can control both are optimal. TNF blockers are regarded as effective treatment for both skin and joint aspects of psoriatic arthritis. Methotrexate, photochemotherapy, PUVA, retinoic acid, and cyclosporine A may help both skin and joint manifestations as well.

There are newer drugs available for psoriatic arthritis that may be considered, too:

Gaining Control Over Psoriatic Arthritis

Interestingly, at one time, psoriatic arthritis was thought to be a mild disease. In fact, psoriatic arthritis is more severe than originally thought. The consensus of scientific literature has revealed that, in terms of progressive joint damage, poorer prognosis is related to:

  • A higher number of joints with active inflammation
  • Elevated sedimentation rate and CRP
  • Joint damage evident on x-rays
  • Failure to achieve adequate response with certain medications
  • Functional limitations
  • Poor quality of life

To gain control over psoriatic arthritis, it is imperative that you be evaluated, diagnosed, and treated by a rheumatologist. People with psoriatic arthritis who receive early treatment have the best chance for controlling disease progression and joint damage. It is also known that psoriatic arthritis is associated with comorbidities, an increased risk of complications, and increased mortality—another reason why early treatment is important.

Managing psoriatic arthritis successfully requires that you be compliant with your treatment plan, exercise, use joint protection techniques, maintain your ideal weight, and manage the comorbidities (e.g., cardiovascular disease).

A Word From Verywell

Psoriatic arthritis has been called a unique inflammatory arthritis because of its association with psoriasis. That, along with potential complications and associated comorbid conditions, make it necessary to get effective treatment underway quickly. The goal for people with psoriatic arthritis is to manage the disease well and limit its impact on quality of life. At Verywell, we have provided you with the facts you need to know about psoriatic arthritis. That knowledge will allow you to understand your doctor's directives, to formulate questions to ask your doctor, and to be encouraged by the effective treatment options, including some that are relatively new.

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