How Is Psoriatic Arthritis Linked to Psoriasis?

Psoriatic arthritis is a condition that affects many people who have psoriasis with skin symptoms. Like psoriasis, psoriatic arthritis is an autoimmune condition with symptoms that are caused by inflammation. Both conditions are also chronic, meaning that they are lifelong conditions, even though symptoms may come and go over time1.

The psoriatic form of arthritis causes inflammation in a person’s joints. If it is not treated, psoriatic arthritis can cause serious damage to a person’s joints very quickly (sometimes after just 6 months). Healthcare providers monitor patients with psoriasis for symptoms of psoriatic arthritis because early detection and treatment of the condition is so important to prevent damage to the joints that can be very serious or permanent2.

What are the symptoms of psoriatic arthritis?

Some of the most common symptoms of psoriatic arthritis include1:

  • Swelling, stiffness, pain, and/or tenderness in the joints or the joint areas
  • Limited ability to move the joints
  • Swollen fingers and/or toes
  • Tiredness and fatigue
  • Nail symptoms, such as pitting or having the nail separate from the nail bed

The most common location of psoriatic arthritis symptoms is in the joints of the fingers or toes, especially in the joints that are closest to the nails2. Many patients also experience symptoms in the knees, ankles, wrists, hips, and lower back. Most patients have symptoms that affect different joints on each side of the body. Symptoms such as stiffness are often worse in the morning than at other times of the day.

Are there different types of psoriatic arthritis?

The symptoms of psoriatic arthritis can be mild, moderate, or severe. Symptoms can appear quickly, or they can develop at a slower pace. Some people have psoriatic arthritis symptoms that affect one or a small number of joints; others may have many affected joints.

There are several different types of psoriatic arthritis that differ according to the location of the symptoms and how much of the body is affected. Oligoarticular psoriatic arthritis affects between 1 and 4 joints in the body, so it is a relatively mild form of the condition. Polyarticular psoriatic arthritis is a more severe form of the condition, which is diagnosed if more than four joints in the body are affected1. 

Some people with psoriatic arthritis have inflammation in the areas where tendons and ligaments connect to the bone. This is called enthesitis, and it can affect the bottom of the foot, the back of the heel, the ribs, the spine, or the pelvis.

Dactylitis is a form of inflammation affects an entire finger or toe, causing it to swell up. It often affects multiple fingers and/or toes of each side of the body. This condition is sometimes called sausage digits.

How is psoriatic arthritis linked to plaque psoriasis?

About 85% of people who develop psoriatic arthritis in their joints had psoriasis skin symptoms first. Most of those patients have mild psoriasis and have had skin symptoms for years before they develop joint symptoms1. Nail involvement is often one of the first signs that people with plaque psoriasis will also develop psoriatic arthritis5.

However, many patients with both conditions find that their joint symptoms and skin symptoms do not usually flare up at the same time2. Further, research has shown that there does not seem to be a direct link between the severity of the two conditions among people who have both of them3. For example, having severe skin symptoms does not necessarily mean that you will also have severe joint symptoms, and vice versa.

How common is psoriatic arthritis?

Researchers estimate that up to 1% of people in the United States will develop psoriatic arthritis and that about 30-40% of people with plaque psoriasis will go on to develop psoriatic arthritis at some point2. Although people of any age can develop psoriatic arthritis, it usually happens after the age of 30 and before the age of 50.

Like psoriasis of the skin, psoriatic arthritis tends to run in families3. Around 40% of people with psoriatic arthritis have a relative who also has had psoriasis or psoriatic arthritis. Having a parent or sibling with psoriatic arthritis makes a person about 50 times more likely to develop the condition than someone without this family link4.

How is psoriatic arthritis treated?

If you are diagnosed with psoriatic arthritis, it is very important to start and maintain a treatment regimen in order to control your symptoms and prevent serious damage to your joints. You may be referred to a rheumatologist, which is a physician who specializes in diagnosing and treating arthritis. To diagnose psoriatic arthritis, the rheumatologist will need to rule out other conditions that have similar symptoms, such as rheumatoid arthritis2.

Treatment options for psoriatic arthritis depend upon how severe the symptoms are and where they are located. For mild psoriatic arthritis that affects 1-4 joints, treatment may include3:

  • Pain relievers called nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Heat and ice therapy
  • Physical therapy
  • Injections of corticosteroid medicine directly into the affected joint

If symptoms are affecting multiple joints and the psoriatic arthritis is moderate or severe, patients may need stronger types of treatments. These may include medicines called disease-modifying antirheumatic drugs (DMARDs). Examples of DMARDs are methotrexate, sulfasalazine, leflunomide, and cyclosporine. DMARDs can help to improve both skin and joint symptoms, but they cannot prevent the longer-term joint damage that psoriatic arthritis can cause4.

Biologic therapies work by affecting the body’s immune system to prevent the inflammation that is the underlying cause of the symptoms, and can help to prevent joint damage. Biologic therapies that may be recommended for people with psoriatic arthritis include6:

Written by: Anna Nicholson | Last reviewed: July 2016.
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