The short answer: People do get psoriatic arthritis (PsA) without psoriasis — although it’s pretty rare — and most often they will have a first-degree relative [sibling or parent] with skin psoriasis,” says Rebecca Haberman, MD, a rheumatologist at NYU Langone in New York City.
Psoriatic arthritis is a type of inflammatory arthritis that often attacks the joints, causing swelling, stiffness, redness, and pain. In most cases, PsA occurs along with cutaneous psoriasis (PsO), or skin and nail inflammation. Your organs can also be affected by out-of-control inflammation, including your heart.
“It’s hard to define the percentage of patients who have PsA without PsO, because in a lot of these patients, the psoriasis can show up after the joint disease — or it’s just not seen,” says Dr. Haberman. “In our cohort of PsA patients, 99.1 percent have skin involvement.”
Psoriasis is often located in “hidden areas, like the umbilicus and gluteal fold that are not routinely checked when a patient sees their primary care provider for a sore foot,” says Susan M. Goodman, MD, a rheumatologist at Hospital for Special Surgery in New York City. “The hope is that better epidemiologic studies will ensure that PsA patients don’t have hidden disease.”
Why Is Psoriatic Arthritis So Tricky to Diagnose?
Unfortunately, having at least one misdiagnosis prior to being diagnosed with psoriatic arthritis is very common. According to a 2018 study conducted by our parent non-profit organization, the Global Healthy Living Foundation, 96 percent of people ultimately diagnosed with PsA reported being misdiagnosed with a different condition first.
“Some of the delay may be due to difficulty among primary care providers to recognize that the patient has inflammatory arthritis,” says Dr. Goodman.
Psoriatic arthritis has come to the forefront of both rheumatology and dermatology fairly recently, explains Dr. Haberman, so health care providers don’t always know all of the signs or the symptoms or when to refer a rheumatologist. A rheumatologist is a specialist who diagnoses and treats musculoskeletal disease and systemic autoimmune conditions known as rheumatic diseases.
PsA can also be easily mistaken for other types of inflammatory arthritis, including osteoarthritis, rheumatoid arthritis, gout, axial spondyloarthritis, or reactive arthritis.
For example, if you only have pain in the big toe joint, it can be mistaken for gout, says Dr. Haberman. On the other hand, if you have asymmetrical joint pain and lower back pain, a doctor may initially suspect axial spondyloarthritis, which impacts the vertebrate in your spine and the area where your spine meets the pelvis, known as the sacroiliac joints.
Symptoms of Psoriatic Arthritis
Psoriasis appears first in about 85 percent of patients who are diagnosed with PsA. But while the presence of psoriasis (especially on the scalp, nails, or groin) is certainly a big clue, it’s not required to make a PsA diagnosis.
According to Dr. Goodman, you should see a rheumatologist if you are experiencing the following distinctive characteristics of PsA, with or without skin involvement.
- Red, hot, swollen joints (or one joint)
- Pain and stiffness that worsen with rest (you feel worse when you wake up in the morning)
- Pain and stiffness that respond symptomatically to anti-inflammatory medications
- Joint pain and another change in your well-being (i.e. joint pain and fatigue)
- Enthesitis (swelling of the ligaments and tendons at the site of insertion to the bone, including the Achilles, plantar fascia, or elbows)
- Dactylitis (swollen, sausage-like fingers or toes)
- Fingernail or toenail abnormalities, like pitting or ridging
- Inflammatory back pain
If a patient has these symptoms, they should see a rheumatologist who will talk about your personal and family health history, give you a physical exam, and take multiple lab and imaging tests, says Dr. Haberman.
To make a diagnosis, your rheumatologist will do bloodwork to check for inflammation or genetic markers that point to other types of inflammatory arthritis or PsA:
- Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) to help rule out osteoarthritis and non-inflammatory arthritis
- Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) to help rule out rheumatoid arthritis
- HLA-B27 to help rule out axial spondyloarthritis
- Uric acid levels to rule out gout (although people with PsA can also have high uric acid levels)
Confirming a diagnosing of PsA may also involve multiple imaging tests (such as X-rays and MRIs) to show joint damage, joint disfiguration, or inflammation in the joint or entheses.
How PsA Without PsO Is Treated
When it comes to diagnosing and treating PsA, the earlier, the better. Even a mere six-month delay can impact your disease outcome over the long term, says Dr. Haberman. And this may mean using stronger medications with potentially more side effects, according to Elaine Husni, MD, MPH, a rheumatologist at the Cleveland Clinic in Ohio.
Once a proper diagnosis is made — which for about 30 percent of patients still, unfortunately, takes more than five years — your treatment plan should factor the part(s) of your body impacted as well as the severity of your symptoms, according to clinical treatment guidelines by the American College of Rheumatology (ACR) and the National Psoriasis Foundation (NPF).
In other words, you’ll need to work with your rheumatologist to figure out the most problematic symptoms and areas for you (dactylitis, enthesitis, back pain, etc.) and then try treatments that best target those areas, explains Dr. Husni.
“There is no real difference in the treatment of psoriatic arthritis with or without psoriasis,” says Dr. Goodman. Both cases will likely involve a bit of trial and error to determine which medication works best for your system.
Common treatment and medications for PsA include:
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Local glucocorticoid injections
- Oral small molecules (OSMs)
- Tumor necrosis factor inhibitor (TNFi) biologics,
- Interleukin-17 inhibitor (IL-17) biologics
- IL-12/23 inhibitor biologics
- IL-23 inhibitor biologics
- JAK inhibitors
“While we have a lot of medication options for PsA, at the outset, we still don’t know which medications will work best for which patient,” says Dr. Haberman. “Psoriatic arthritis is a very complex, heterogeneous disease that can present in many different ways.”
In addition to complying with your treatment plan, it’s of paramount importance to not smoke, maintain a healthy body weight, and exercise, all of which can decrease the risk of developing comorbidities of PsA like heart disease and interfere with the effectiveness of certain PsA medications, adds Dr. Goodman.
If you’re experiencing pain, stiffness, and swelling and have a relative with psoriasis, don’t write it off as a minor injury. “Even if the swelling goes away, you can still be having underlying damage to the joint so you don’t want to ignore your symptoms,” says Dr. Haberman, noting that a lot of people with psoriasis don’t even know about PsA.
“We are actually trying to raise awareness. Read articles, associate yourself with CreakJoints, and if you have any questions, see a rheumatologist,” she says.
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Clinical manifestations and diagnosis of psoriatic arthritis. UpToDate. https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-psoriatic-arthritis.
Feld J, et al. Axial disease in psoriatic arthritis and ankylosing spondylitis: a critical comparison. Nature Reviews Rheumatology. May 2018. doi: https://doi.org/10.1038/s41584-018-0006-8.
Interview with Elaine Husni, MD, MPH, a rheumatologist at the Cleveland Clinic in Ohio
Interview with Rebecca Haberman, MD, a rheumatologist at NYU Langone in New York City
Interview with Susan M. Goodman, MD, a rheumatologist at Hospital for Special Surgery in New York City
Ogdie A, et al. Diagnostic experiences of patients with psoriatic arthritis: misdiagnosis is common. Annals of the Rheumatic Diseases. June 2018. doi: https://doi.org/10.1002/acr.23174.
Psoriatic Arthritis. American College of Rheumatology. https://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Psoriatic-Arthritis.
Psoriatic arthritis. Genetics Home Reference. U.S. National Library of Medicine. https://ghr.nlm.nih.gov/condition/psoriatic-arthritis#inheritance.
Singh JA, et al. 2018 American College of Rheumatology/National Psoriasis Foundation Guideline for the Treatment of Psoriatic Arthritis. Journal of Psoriasis and Psoriatic Arthritis. January 2019. doi: https://doi.org/10.1177/2475530318812244.