Fibromyalgia and Psoriatic Arthritis: What’s the Difference?

Fibromyalgia and psoriatic arthritis (PsA) are often confused because they share similar symptoms. This can lead to confusion and misdiagnosis. To add to the complexity, some people have both fibromyalgia and PsA at the same time. In fact, 15 to 25 percent of people with PsA also have fibromyalgia.^1,2

But even though they can look similar, they are two different conditions that require different treatment. Understanding how they are different can help you get the right diagnosis and treatment.¹

What is fibromyalgia?

Fibromyalgia is a widespread pain disorder. It is caused by dysfunction in the way the brain processes pain signals. For those with this condition, pain sensitivity is much higher than normal. The condition is more common in women than men.^1,2

Fibromyalgia causes musculoskeletal pain (pain in the bones, muscles, tendons, and ligaments) and tenderness. Other symptoms of fibromyalgia include:^1,2

• Fatigue
• Brain fog/li>
• Headaches/li>
• Mood changes/li>
• Difficulty sleeping/li>

Overlapping symptoms of fibromyalgia and psoriatic arthritis

Both fibromyalgia and PsA are chronic conditions that cause pain and discomfort in various parts of the body. Both conditions can have flare-ups (when symptoms get worse) and periods of remission (when symptoms go away for a time). People with both conditions often experience:^1-3

• Widespread bone and joint pain
• Fatigue
• Brain fog
• Sleep issues

How are they different?

While fibromyalgia and PsA present similar symptoms, they have totally different causes. Fibromyalgia is a disorder of the central nervous system. It affects the way the brain and body process pain. Even though the pain is very real, the condition does not cause damage to the joints.^1-3

PsA, on the other hand, is an autoimmune condition. This is when the immune system mistakenly attacks healthy, normal cells in the body. In PsA, there is damage to the joints. The damage can worsen over time if left untreated. And in some severe cases, surgery may be necessary to treat joint damage.^1,2

Another key difference is where pain occurs. Fibromyalgia typically involves widespread pain affecting the muscles and soft tissues throughout the body. People with this condition often have very tender areas. Unlike PsA, fibromyalgia is not linked to inflammation.¹

In contrast, PsA causes pain, stiffness, and swelling in the joints. PsA can affect any joint in the body, but it particularly affects the fingers, toes, wrists, knees, and ankles. In addition to joint symptoms, people with PsA also may have:^1,4

• Psoriasis – A skin condition in which red, scaly patches form on the skin
• Nail changes – Nails become brittle and weak, and they may have pitting
• Uveitis – Inflammation in the eye that causes redness, pain, and even vision loss in severe cases

Why are they often misdiagnosed?

The overlapping symptoms of fibromyalgia and PsA can lead to misdiagnosis. Since the conditions share common features like pain and fatigue, doctors may struggle to tell them apart. This can lead to delayed treatment or treatment for the wrong condition that does not work.¹

How healthcare providers distinguish between them

A rheumatologist is best suited to treat both fibromyalgia and PsA. This is a doctor who specializes in the joints, bones, and muscles. Here are some things they might do to distinguish between the 2 conditions (and rule out others):¹

• Medical history – Your doctor will need a detailed medical history to help get the right diagnosis. This should include any history of psoriasis or family history of autoimmune diseases. Both fibromyalgia and PsA have been shown to run in families.
• Physical exam – Your doctor will assess any joint tenderness, swelling, and skin changes you may have.
• Diagnostic tests – Your doctor may order blood tests to rule out other conditions. They may also suggest imaging like ultrasound, X-rays, and MRI scans. These tests can check for any inflammation or joint damage that might be caused by PsA.
• Response to treatment – Fibromyalgia and PsA require different treatment approaches. So, if you are still having widespread pain even after being on PsA treatment, the pain may be due to fibromyalgia.

For both these conditions, early diagnosis and treatment are crucial. The earlier you are diagnosed, the better your outcomes will be. You also will be less likely to have long-term complications.