If you have?psoriatic arthritis?(PsA) and experience persistent pain and fatigue, you may also need to be evaluated for another chronic disorder known as?fibromyalgia. The two conditions often occur together and share some symptoms, but they require different treatments.
People who have psoriatic arthritis are at greater risk of developing fibromyalgia,?according to the National Fibromyalgia Association, yet rheumatologists may not realize that their patients with psoriatic arthritis in fact have both conditions.
“Sometimes people with psoriatic arthritis are on their fourth or fifth rheumatologist before a rheumatologist realizes they might have both,” says?Philip Mease,?MD, a rheumatologist at Swedish Medical Center in Seattle and a clinical professor at the University of Washington School of Medicine in Seattle. “Keep in mind that a person with psoriatic arthritis can have other forms of arthritis as well.”
Diagnosis: Psoriatic Arthritis
Psoriatic arthritis occurs when the immune system begins to attack healthy cells and tissues. The abnormal immune response causes joint inflammation and the overproduction of skin cells.
Psoriatic arthritis affects more than 8 million people in the United States, according to the National Psoriasis Foundation.
Both psoriatic arthritis and fibromyalgia can result in pain and fatigue, but people with psoriatic arthritis have these symptoms that differentiate the condition from fibromyalgia:
- Tender, swollen joints
- The swelling of a whole toe or finger, referred to as “sausage digits”
- Scaly skin psoriasis plaques or nail psoriasis resulting in discolored, pitted, grooved, or crumbling nails, or nails that are raised from the nail bed
Around 30 percent of Americans with psoriasis develop psoriatic arthritis, according to the National Psoriasis Foundation, so doctors considering a psoriatic arthritis diagnosis will look for the skin or nail symptoms of psoriasis and ask if psoriasis runs in the family.
There isn’t a specific test to diagnose psoriatic arthritis. To rule out other causes of joint pain and stiffness, such as osteoarthritis or rheumatoid arthritis, doctors rely on a combination of tests:
- Blood tests that look for markers of inflammation without rheumatoid antibodies
- MRIs or ultrasounds that can reveal inflammation consistent with enthesitis, a condition affecting the areas where tendons or ligaments connect to bones
- X-rays that can show damage from early disease
Doctors may also remove a small sample of fluid from one of the affected joints. If the test reveals uric acid crystals, the diagnosis may be gout rather than psoriatic arthritis.
Early diagnosis of psoriatic arthritis is vital in order to get treatment that can prevent or slow joint damage.
Unlike psoriatic arthritis, fibromyalgia is not thought to be an autoimmune or inflammatory disease, according to the American College of Rheumatology. Research suggests that the nervous system is involved, particularly the brain and spinal cord.
Fibromyalgia affects about 4 million adults in the United States, says the Centers for Disease Control and Prevention (CDC), with women twice as likely to have the condition as men.
Certain symptoms of fibromyalgia may distinguish the condition from psoriatic arthritis:
- Pain all over the body (known as widespread pain)
- Problems with thinking, memory, and concentration, known as “brain fog” or “fibro fog”
- Sleep problems, including waking feeling unrefreshed
- Abdominal pain or bowel problems
- Numbness or tingling in the hands and feet
- Restless legs
- Frequent urination
As with psoriatic arthritis, there’s no test for fibromyalgia. It is mostly a diagnosis of exclusion, with doctors performing lab tests or X-rays to rule out other problems, according to the American College of Rheumatology.
A challenge for rheumatologists is knowing when widespread pain that appears to be enthesitis from psoriatic arthritis is actually a sign of fibromyalgia. Doctors may have special difficulty diagnosing patients who are overweight, explains Marina Magrey, MD, a professor of medicine at Case Western Reserve University School of Medicine at MetroHealth in Cleveland.
Doctors might consider how well a patient with widespread pain does on medications that tend to work well for people with psoriatic arthritis, such as NSAIDs (nonsteroidal anti-inflammatory drugs) like?ibuprofen (Advil, Motrin), naproxen (Aleve), and etodolac (Lodine). “Most patients with fibromyalgia may not have substantial improvements with NSAIDs alone,” Dr. Magrey says.
What Causes Psoriatic Arthritis and Fibromyalgia?
It’s not entirely clear why some people develop psoriatic arthritis, but researchers believe that the cause may be a combination of genetic vulnerabilities and triggers such as infection, stress, and physical trauma.
Anyone can develop psoriatic arthritis, but it most often occurs in adults between age 30 and 50, says the National Psoriasis Foundation.
Researchers don’t know the exact cause of fibromyalgia either, but as with psoriatic arthritis, genetics seems to play a role. Fibromyalgia tends to run in families, and there may be certain genetic mutations that may make someone more susceptible.
The CDC says that age is also a risk factor for fibromyalgia: While it can affect people of all ages, most people are diagnosed during middle age, and the risk increases as you get older. People who’ve had lupus or rheumatoid arthritis are more likely to develop fibromyalgia.
Other possible risk factors for fibromyalgia, according to the CDC, include the following:
- Stressful or traumatic incidents, such as a car accident, or post-traumatic stress disorder
- Injury from repetitive stress to a joint such as knee bending
- Illness such as a viral infection
- Family history
If you have both psoriatic arthritis and fibromyalgia, it’s important that your doctor recognizes that you have both conditions. For one thing, getting a correct diagnosis will help your doctor prescribe the right kinds and amounts of psoriatic arthritis medications. “If a doctor doesn’t recognize the presence of fibromyalgia, he or she could increase the dosage of powerful [psoriatic arthritis] drugs or switch drugs unnecessarily,” says Dr. Mease.
There is no known cure for fibromyalgia, but medication and other therapies (such as psychological and behavioral interventions) can help relieve symptoms. “The first treatment for fibromyalgia is often with a nonaddictive sleep aid, because fibromyalgia disrupts phase 4 sleep, which is the deep sleep that’s most restful and restorative,” says Dr. Magrey.
“To relieve pain associated with fibromyalgia, we usually prescribe gabapentin, pregabalin, and selective serotonin and norepinephrine reuptake inhibitors like Cymbalta and milnacipran,” Magrey says, adding that rheumatologists might also prescribe NSAIDS and muscle relaxants.
Aerobic and resistance exercise is also important for reducing pain and enhancing quality of life for people with psoriatic arthritis or fibromyalgia. Consider water exercises such as water walking, water aerobics, and swimming —?low-impact activities that won’t stress joints.
“It may take three weeks before exercising doesn’t hurt,” Magrey says. ”But then you’re up the hill, and exercising will feel much better.”
Additional reporting by Barbara Kean.