Whether you’ve been diagnosed or know a friend or family member who has, here’s a guide to the basics of psoriatic arthritis.
What is psoriatic arthritis?
Psoriatic arthritis (PsA) is an autoimmune disease that occurs in up to 40% of people with psoriasis. Psoriasis is an inflammatory disease that affects the skin, causing red, scaly patches that are often painful and itchy. Both conditions are chronic, lifelong diseases, although symptoms may come and go over time. In the majority of cases, the skin disease (psoriasis) precedes joint disease (psoriatic arthritis), and PsA often develops within 5-10 years from the onset of psoriasis. However, in about 10-15% of patients, PsA will develop before psoriasis.
So PsA is an autoimmune disease – what does that mean?
PsA is categorized as an autoimmune disease—the immune response is abnormally activated, and it begins to attack healthy tissue. As a result, people with PsA experiences chronic inflammation and joint pain. Additionally, they could experience uvelitis, hearing loss, mood changes (depression), chronic fatigue, and other negative symptoms. People with autoimmune diseases usually fluctuate between periods of remission (little or no symptoms) and flare-ups (worsening symptoms). There are over 80 autoimmune diseases. Examples include: rheumatoid arthritis, psoriasis, Sjögren’s syndrome, lupus, inflammatory bowel disease (IBD), multiple sclerosis, and type 1 diabetes.
How is psoriatic arthritis different from rheumatoid arthritis?
Although some characteristics of PsA resemble those of Rheumatoid Arthritis (RA), PsA can be distinguished from RA by several features:
- Blood test results: Oftentimes, individuals with RA will have an antibody present in their blood known as rheumatoid factor.
- Specific joints affected: PsA often affects distal joints in the fingers and toes and in the lower back. Conversely, RA tends to affect a different set of joints, such as those in the middle of fingers and toes, as well as at the wrist. Additionally, joint pain with PsA is typically asymmetrical versus the more uniform RA.
- PsA affects much more than just joints: PsA often goes beyond just bones to affect tendons, skin, nails, and even the eyes. This can lead to a wide host of related conditions, such as plantar fasciitis, conjunctivitis of the eye, and most commonly, psoriasis of the skin. Although one doesn’t have to have psoriasis to have PsA, it is a very common comorbidity.
What causes psoriatic arthritis?
PsA is a chronic, inflammatory arthritis that occurs in up to 40% of people diagnosed with psoriasis. While the exact cause of PsA is unknown, experts have discovered that there are genetic and environmental factors that may combine to trigger the disease. Several studies have found a link between genetics and PsA. The prevalence of PsA among first-degree relatives is shown to be 49 times higher than the prevalence in the general population. Additionally, there are a few studies to indicate that environmental factors—including viruses and physical trauma—may be to blame for PsA.
Is all psoriatic arthritis the same? What are the different kinds?
PsA is a progressive disease, which means that symptoms tend to worsen over time. There are three types—characterized by the disease severity: mild, moderate, and severe. Mild disease is generally characterized by oligoarticular PsA and has minimal impact on the person’s quality of life. Moderate disease shows an impact on the daily tasks of living and physical functions. Moderate disease may also impact the mental well-being of the person and shows a lack of response to mild treatment, such as with non-steroidal anti-inflammatory drugs (NSAIDs). Severe disease greatly impacts the person’s quality of life. With severe disease, a person cannot perform major daily tasks of living without pain or dysfunction. There is a large impact on both physical and mental well-being.
How is psoriatic arthritis diagnosed?
Rheumatologists, who specialize in the diagnosis and treatment of musculoskeletal disease and systemic autoimmune conditions, most often handle a PsA diagnosis. Because most people first develop the skin condition, psoriasis, a dermatologist may be the first physician to recognize the person’s symptoms as PsA.
Several areas are assessed when evaluating a patient for PsA, including:
- Peripheral joint assessment (where the doctor checks 68 joints for tenderness and 66 joints for swelling)
- Pain (which is patient reported)
- Patient assessment of disease activity
- Physical function (as measured by a health assessment questionnaire)
- Health-related quality of life
- Fatigue (which is patient reported)
- Acute phase reactants (for example, C-reactive protein or erythrocyte sedimentation rate measured by laboratory testing)
In addition, imaging is usually performed to view the affected joints, including x-rays, ultrasounds, MRIs, and/or CT scans.
To aid in diagnosis, researchers have sought to create standardized diagnostic criteria. The most recent and well established are the Classification Criteria for Psoriatic Arthritis (CASPAR) criteria, which assess a patients’ personal and family history of psoriasis, as well as the patient’s physical symptoms of disease.
How is psoriatic arthritis treated? Is there a cure?
There is no cure for PsA; however, there are ways to manage the symptoms of PsA. Treatment for PsA varies depending on the severity of the disease and specific symptoms that are the most problematic at the time.
Treatment may include medication to reduce inflammation (NSAIDs, DMARDs, and/or biologics), steroid injections, or joint replacement surgery. In addition, common non-pharmacological treatment options used in psoriatic arthritis include physical or occupational therapy and phototherapy (light therapy) for psoriasis lesions. Physical and occupational therapy are often critical interventions to protect the involved joints and maintain function.
While treatment won’t cure PsA or reverse joint damage, it can help stop the progression of PsA and slow the impact of chronic inflammation to other parts of the body.
How can I manage my psoriatic arthritis?
In addition to medical treatment, exercise is an important part of managing PsA pain and maintaining the range of motion in joints. Low-impact exercise has been shown to reduce pain and improve well-being in people with PsA.
Research has also identified that people living with PsA are more likely to experience depression and anxiety. Coping strategies are critical to emotional and mental health, and include support groups (online or in person), seeing a mental health counselor, or going to a therapist.
Finally, for some people, adaptations to the home or work are necessary to ensure safety and functioning. Assistive devices, including modified kitchen utensils, walking canes, shoe inserts, and large button telephones, can help protect painful, inflamed joints and make it easier to accomplish everyday tasks.