Psoriatic Arthritis vs. Fibromyalgia: What Are the Differences?

Symptoms, Causes, Treatment

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Psoriatic arthritis (PsA) and fibromyalgia are two very painful and life-altering health conditions. While each condition has its unique features, they do share many common characteristics.

PsA is a type of inflammatory arthritis that causes joint and tissue inflammation throughout the body. It can also affect the skin. Fibromyalgia also affects the muscles, tendons, and other soft tissues, causing whole-body pain.

These two conditions can exist alone or together. Living with both PsA and fibromyalgia can be quite a challenge, so it is important to manage and treat both conditions.

This article will discuss the similarities between PsA and fibromyalgia, their symptoms and causes, and how they are treated and diagnosed.

Muscle disease

Patrik Giardino / Getty Images

Symptoms

Both PsA and fibromyalgia are painful conditions that cause whole-body symptoms. Common symptoms of both conditions include pain, chronic fatigue, and brain fog. PsA might also cause sleep disturbances, anxiety, depression, and numbness and tingling of the limbs, which are more frequently seen in fibromyalgia.

Psoriatic Arthritis
  • Swollen, tender joints

  • Swelling of the whole fingers and toes

  • Scaly skin plaques

  • Nail psoriasis

  • Chronic fatigue

  • Back and shoulder pain

  • Enthesitis

  • Chest and rib pain

  • Brain fog

Fibromyalgia
  • Widespread pain, including muscle pain and spasms

  • Stiffness upon awakening or after sitting for too long

  • Brain fog

  • Gastrointestinal troubles

  • Jaw and facial tenderness

  • Sensitivity to lights or smells

  • Anxiety and/or depression

  • Numbness and tingling in the limbs

  • Bladder troubles, including frequent urination

  • Reduced tolerance to physical activity

  • Headaches

  • Chronic fatigue

  • Costochondritis


Symptoms of PsA

PsA is an autoimmune disease—that means it is the result of your immune system attacking healthy cells and tissues. An abnormal tissue response leads to joint inflammation and the overproduction of skin cells.

PsA affects between 3.6 and 7.2 per 100,000 people worldwide. Prevalence in the United States ranges from about 0.06% to 0.25%. PsA affects about 30% of people with the inflammatory skin condition psoriasis.

Symptoms of PsA that might differentiate it from fibromyalgia include:

  • Tender, swollen joints
  • Dactylitis: Swelling of whole fingers and toes
  • Scaly skin plaques
  • Nail psoriasis: Including discolored, pitted, and crumbling nails and nailbed separation
  • Tendon and/or ligament pain
  • Reduced range of motion
  • Inflammation and redness of the eyes
  • Back and shoulder pain
  • Enthesitis: Inflammation in the areas where the muscle connects to a bone
  • Chest and rib pain: While fibromyalgia doesn’t cause chest and rib pain seen in people with PsA, it does cause a condition called costochondritis, a type of non-cardiac chest pain that inflames the cartilage connecting the ribs to the breastbone.

PsA tends to be a condition that will flare up with severe or increased symptoms that may last for days, weeks, or months. These symptoms can subside, and you will experience periods where the disease is milder or less severe. It is also possible to experience remission—periods of minimal disease activity.

Fibromyalgia Symptoms

Fibromyalgia affects around 4 million adults in the United States—about 2% of American adults, according to the Centers for Disease Control and Prevention (CDC). The majority of people with the condition are female.

Doctors don’t consider fibromyalgia to be an autoimmune disease or an inflammatory condition. According to the American College of Rheumatology (ACR), it is believed that fibromyalgia is a problem of the nervous system, specifically of the brain and the spinal cord.

The pain and tenderness from fibromyalgia will come and go and affect various parts of the body. It tends to be a lifelong problem that commonly causes widespread muscle pain, severe fatigue, and sleep problems.

Additional symptoms of fibromyalgia are:

  • Muscle cramping and spasms
  • Stiffness upon awakening or after sitting for too long
  • Brain fog (difficultly remembering and concentrating)
  • Gastrointestinal troubles, including nausea, bloating, and constipation
  • Jaw and facial tenderness
  • Sensitivity to lights or smells
  • Anxiety and/or depression
  • Restless legs, numbness, and tingling in the limbs
  • Bladder troubles, including frequent urination
  • Reduced tolerance to physical activity
  • Headaches

Can PsA and Fibromyalgia Coexist?

Fibromyalgia affects up to 18% of people with PsA. People with PsA who also have fibromyalgia tend to have a worse disease course with PsA than those with PsA alone.

A study reported in 2016 in the Journal of Rheumatology by researchers at Tel Aviv University looked at 73 people with PsA, the majority of whom were female (57.5%). Using the American College of Rheumatology criteria for fibromyalgia, the condition was diagnosed in 13 people—12 of whom were female.

Researchers also determined that having fibromyalgia with PsA might lead to worse disease activity scores. They concluded that the impact of fibromyalgia should be considered when treating people with PsA and that doctors should avoid unnecessary changes to treatment.

Causes

The causes for both psoriatic arthritis and fibromyalgia are not easily understood, but researchers do have some theories as to what might cause these two conditions.

PsA Causes

Researchers believe PsA is caused by a combination of factors, including genetics (inheritance) and triggers, such as infections, stress, and physical trauma.

Recent research suggests that people with PsA have high levels of tumor necrosis factor (TNF)—an inflammatory protein—in their joints and affected skin areas. The increased levels overwhelm the immune system and make it harder to stop the inflammation caused by PsA.

The people with the highest risk of PsA are those who already have psoriasis. Still, it is possible to have PsA without psoriasis or to have psoriasis and never develop PsA. PsA occurs most frequently in adults ages 35 to 55, but it can affect anyone regardless of age. It affects males and females equally. 

A family history of PsA and/or psoriasis also increases your risk of PsA. Children who have a parent with PsA or psoriasis have a greater risk of PsA. According to the Cleveland Clinic, the most common age for juvenile-onset PsA is 9 to 11 years.

Fibromyalgia Causes

Researchers aren’t entirely sure what causes fibromyalgia, but most speculate that genetics might play a role. This is because fibromyalgia tends to run in families. Newer research suggests that having certain gene mutations (which might also run in families) makes someone more susceptible to developing fibromyalgia.

Anyone can get fibromyalgia, including children. However, most people diagnosed with the condition are in middle age, and the risk for fibromyalgia increases as you get older.

Females are twice as likely as males to have fibromyalgia. Up to 20% of people with the condition also have other chronic diseases, like PsA, rheumatoid arthritis, and lupus.

Diagnosis

Because PsA and fibromyalgia cause common symptoms, it is important to properly distinguish one from the other to determine the best course of treatment.

PsA Diagnosis

There is no one specific test to confirm a PsA diagnosis. The condition is diagnosed using various methods to rule out other causes of joint pain and stiffness.

Tools your doctor might employ to determine PsA and rule out other conditions include: 

  • Physical examination of skin and joints
  • Review of family and personal history
  • Blood tests that look for specific inflammation markers
  • Imaging, including X-rays, magnetic resonance imaging (MRI), and ultrasound, to reveal inflammation and bone changes
  • Joint aspiration: This involves taking a small fluid sample from an affected joint. The fluid is tested in a lab to look for specific markers of inflammation linked to PsA and other types of inflammatory arthritis.

An early diagnosis of PsA is vital to prevent and slow down permanent damage to joints. People with PsA can have joint deformities, seen on imaging, very early in the disease.

Fibromyalgia Diagnosis

Like PsA, there isn’t a specific test to diagnose fibromyalgia. Instead, fibromyalgia tends to be a diagnosis of exclusion, meaning your doctor will perform lab work and imaging to rule out other conditions that cause similar symptoms.

This is a challenge because widespread pain is a symptom of many conditions, including PsA. For example, enthesitis from PsA can be mistaken for widespread muscle pain from fibromyalgia and vice versa.  

People with fibromyalgia are more sensitive to pain that doesn’t bother others without the condition, so doctors assess the number of tender areas on the body when determining fibromyalgia.

But not all doctors use the tender point system for diagnosing the condition. Many rely on newer diagnostic criteria from the American College of Rheumatology that pays specific attention to widespread pain and symptoms.

After all other possible conditions have been ruled out, the main symptom required for a fibromyalgia diagnosis is widespread pain that has lasted for three or more months. The definition of “widespread pain,” according to the ACR, is lasting pain in at least four of five regions of the body.

The ACR’s criteria for diagnosis also looks at symptoms experienced that have lasted three or more months, including fatigue, sleep problems, and cognitive problems.

Treatment

There is no cure for PsA or fibromyalgia, but both are treatable and manageable. Because these conditions have different causes and underlying processes, they require different treatment methods.

Goals for treating PsA include reducing pain and other symptoms and preventing joint damage. Most people with the condition take medications regularly to keep inflammation in check and to manage pain and swelling.

Medicines used to treat PsA include nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroidsdisease-modifying antirheumatic drugs (DMARDs), and biologics.

Treatment for fibromyalgia includes lifestyle therapies and medications to improve symptoms. Medicines used to treat the condition include antidepressants and prescription and over-the-counter pain relievers.

Other therapies for fibromyalgia include improving sleep habits, stress management, cognitive behavioral therapy, and physical therapy, including strength training and exercise.

Prevention

Conditions like psoriatic arthritis and fibromyalgia generally cannot be prevented. However, it is possible to prevent flare-ups of these conditions and work to reduce the frequency and severity of symptoms.

Doctors do not know of any way to prevent PsA, and no treatment can guarantee prevention. Because only a small number of people with psoriasis eventually go on to develop PsA, it is difficult to identify who might go on to get PsA.

A 2019 review aimed to identify the challenges of knowing who might be at risk of PsA. The report’s authors cite the difficulty in trying to predict events that might lead people with psoriasis to develop PsA. They also point to a lack of understanding on how and why the disease progresses and which people would be most at risk.

Most experts concede that fibromyalgia generally is not preventable. Some cases of fibromyalgia might be preventable, especially if they are caused by chronic stress or sleep issues. But if fibromyalgia results from physical trauma (e.g., a car crash) or as a result of genetics, there isn’t a lot you can do about that.

Without knowing what exactly causes fibromyalgia, there is no way of knowing whether the condition truly can be prevented. Regardless, fibromyalgia symptoms can be managed with proper treatment, including the management of triggers like diet, stress, and sleep troubles.

Summary

Psoriatic arthritis and fibromyalgia are two very painful and debilitating conditions. They share many similarities, especially symptoms. They both appear to run in families and are linked to gene mutations and environmental triggers.

No one test can confirm either condition. PsA is diagnosed using a variety of methods, including blood work and imaging. Fibromyalgia, on the other hand, tends to be a diagnosis of exclusion—that is, it cannot be considered until other conditions that cause similar symptoms are ruled out.

There is no cure for PsA or fibromyalgia, but both conditions are treatable. Researchers don’t know if either condition can be prevented, but with fibromyalgia, it is possible to reduce risk factors for the condition.

People who have PsA are at an increased risk of fibromyalgia, but it is often difficult for rheumatologists to recognize fibromyalgia when it coexists with PsA.

A Word From Verywell

If you have psoriatic arthritis and you start experiencing severe fatigue, muscle pain, cramping, spasms, and/or other symptoms of fibromyalgia, reach out to your doctor. If you find your doctor isn’t receptive to your experience, you should consider finding a doctor who better understands fibromyalgia, such as a rheumatologist or a neurologist. This is especially important if fibromyalgia runs in your family. 

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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