About 1.5 million Americans have psoriatic arthritis (PsA), a form of inflammatory arthritis. For many of those people, PsA is only part of the story. That’s because patients may have two or more chronic conditions.
Psoriatic arthritis (PsA) can be difficult to diagnose because it shares symptoms with conditions like rheumatoid arthritis, osteoarthritis, fibromyalgia, and gout.
According to the Psoriatic Arthritis in America 2016 survey, most people who have PsA experience multiple symptoms over a period of years before the condition is properly diagnosed. The survey found that 41 percent of people saw at least four health professionals before a PsA diagnosis was made.
Psoriatic arthritis and rheumatoid arthritis (RA) are autoimmune diseases, in which the immune system mistakenly attacks healthy cells, causing swelling, pain, and stiffness in the joints.
“Psoriatic and rheumatoid arthritis are similar but separate diseases, sometimes with manifestations that look quite similar,” says Mark Genovese, MD, the director of the rheumatology clinic at Stanford Health Care in Palo Alto, California. “In general, the two diseases do not coexist together.”
Dr. Genovese points out, however, that during the months or even years when the arthritis is first developing, the type of arthritis a patient has may be unclear.
One of the features that distinguishes psoriatic arthritis from rheumatoid arthritis is dactylitis, according to Jason Faller, MD, a rheumatologist at Lenox Hill Hospital in New York City. With this condition, fingers or toes swell and take on a sausage-like appearance.
Enthesitis, or inflammation of the areas where ligaments or tendons enter into the bones, is also a characteristic of psoriatic arthritis that does not occur in rheumatoid arthritis or osteoarthritis.
As many as 30 percent of individuals who have psoriasis develop psoriatic arthritis, according to the National Psoriasis Foundation. Signs of the condition, such as red, scaly skin, can help doctors differentiate PsA from RA.
Dr. Faller notes that many of the treatments are the same for both conditions, but “there are some treatments for psoriatic that don’t treat rheumatoid; and there are some treatments for rheumatoid that don’t treat psoriatic.”
Often both types of arthritis benefit from anti-inflammatory medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and immunosuppressants.
Osteoarthritis, a degenerative joint disease in which the cartilage wears away with age and bone rubs against bone, is the most common form of arthritis and affects about 27 million Americans.
“Virtually everyone will develop osteoarthritis at some point, so you can certainly have osteoarthritis and psoriatic arthritis at the same time,” says Genovese.
While pain relief medication can help manage symptoms of both conditions, osteoarthritis is not an inflammatory joint disease. Treatment also differs because psoriatic arthritis may respond to drugs that target the immune system.
Last year, Diane Talbert of Waldorf, Maryland, who has lived with psoriatic disease for 30 years (she has psoriasis and psoriatic arthritis) was diagnosed with fibromyalgia, a disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory, and mood issues.
“I think it is very common to have [PsA and fibromyalgia] at once. It just gets missed by our doctors,” says Talbert. “The biggest change I noticed was brain fog and fatigue. I felt like my psoriatic arthritis was getting worse. I was having more pain, stiffness, and tenderness in my muscles. It felt like the pain was all over my body. I know with my psoriatic arthritis I had pain also, along with swelling, but the tenderness is in certain joints.”
Talbert stresses that patients have to be aware of changes in their bodies so they can get the proper diagnosis. She started keeping a journal when she noticed she was having symptoms that were different from her usual psoriatic arthritis.
“I was feeling pain in different parts of my body, and the pain would get worse even after I rested,” she says. “I couldn’t sleep but two or three hours. I was tired all the time and couldn't move like I used to. I would get restless legs along with numbness.”
Talbert now takes one medication for her PsA and a different one for her fibromyalgia.
Genovese warns that patients who have psoriatic arthritis can also go on to develop gout, another form of inflammatory arthritis characterized by high levels of uric acid in the blood. This can form uric acid crystals, which may accumulate in the joints and cause pain.
“There’s a higher rate of uric acid formation in patients who have active psoriasis because of the cellular turnover and that may increase the rates of gout in that population,” he says.
Dealing with multiple diagnoses can be a constant challenge, and Talbert says that maintaining a positive attitude is important.
“It can be hard to stay positive all the time, but it can help you deal better with what is going on with you,” she says. “My goal in life is to help find a cure for my diseases, not dwell on what I can't change.”
“I ran a support group for 10 years,” she says. “It was a place where we came together to share our fears, doubts, experiences and just overall life. So many of us are alone with this journey, and we need support so that we don't feel alone.”
Talbert recommends that patients seek out support groups near their homes and look into national resources such as the National Psoriasis Foundation and the International Pain Foundation.