What Is Psoriatic Arthritis?
Psoriatic arthritis (PsA) is a form of inflammatory arthritis. It affects about 1 million people in the United States, or 30% of people who have psoriasis. Psoriasis is a skin disease that causes a red, scaly rash, most often on your elbows, knees, ankles, feet, and hands.
Psoriatic arthritis is an autoimmune condition. It happens when your body’s immune system attacks healthy tissue by mistake. PsA most often affects your skin and your joints, which can become swollen, stiff, and painful. Over time, if you don’t treat it, the inflammation can damage joints and tissues.
Psoriatic Arthritis Symptoms
The symptoms of psoriatic arthritis include:
- Swollen fingers and toes
- Foot pain
- Lower back pain
- Fatigue
- Swelling and pain around tendons
- Stiffness and tiredness in the morning
- Less range of motion
- Nail changes
- Eye redness and pain
- Scaly skin, especially on your knees, elbows, and scalp
Psoriatic arthritis shares some symptoms with rheumatoid arthritis (RA). But RA usually affects joints on both sides of your body. It can also cause bumps under your skin. Other skin and nail changes are more likely with psoriatic arthritis.
Where can psoriatic arthritis affect your body?
This condition can involve different body parts.
- Spondylitis affects your spine and may cause inflammation and stiffness in your neck, lower back, spinal vertebrae, or sacroiliac region (pelvic area), which can make it hard to move. Spondylitis also can attack connective tissue, like ligaments, or cause arthritis in the joints of your arms, hips, legs, or feet.
- Enthesitis is inflammation of entheses, the place where ligaments or tendons insert into your bones. You’re likely to get it on the bottoms of your feet, your Achilles tendons, and the places where ligaments attach to your ribs, spine, and pelvis. It affects only people with PsA, not other types of arthritis like rheumatoid arthritis or osteoarthritis. Over time, enthesitis can make tissues in the affected area ropey (your doctor will call this fibrosis) or solid (the doctor might refer to this as ossification or calcification).
- Dactylitis, or “sausage digits,” is inflammation that affects an entire finger or toe. It happens when small joints and entheses of the surrounding tendons get inflamed. Dactylitis is another hallmark of psoriatic arthritis. It usually involves a few fingers or toes, but not in a symmetrical pattern. Unlike other types of arthritis, PsA can affect different toes and fingers on different sides of your body.
Types of Psoriatic Arthritis
Like other types of arthritis, psoriatic arthritis can be more or less severe. PsA may be:
- Oligoarticular. Usually a milder type that affects four or fewer joints
- Polyarticular. A more severe type that affects four or more joints
Psoriatic Arthritis Causes
Doctors aren’t sure what causes psoriatic arthritis, but these things may play a role:
- Genes. Having a parent with psoriasis triples your chance of getting psoriasis and makes you more likely to have psoriatic arthritis.
- Infection. An infection that sets off your immune system could be to blame. Psoriasis, for example, is often triggered by strep throat.
Psoriatic Arthritis Risk Factors
- Psoriasis. Up to 30% of people with psoriasis get psoriatic arthritis. It affects men and women equally.
- Age. You can get PsA at any age, but it usually affects people between 30 and 50.
- Family history. As many as 40% of people with psoriatic arthritis have a family history of skin or joint disease.
Psoriatic Arthritis Diagnosis
Your doctor will ask about your symptoms and whether any of your relatives have psoriasis, psoriatic arthritis, or another autoimmune disease. They’ll also check how well your joints move and whether you have pain, tenderness, swelling, or warmth. You may have tests including:
- Imaging tests such as X-rays, MRIs, CT scans, and ultrasounds
- Blood tests to rule out other kinds of arthritis and look for signs of inflammation
- Tests of the fluid from your joints or tiny samples of skin
Psoriatic Arthritis Treatment
Medical treatments for psoriatic arthritis include:
- Nonsteroidal anti-inflammatory drugs (NSAIDs). These are over-the-counter medications like ibuprofen and naproxen.
- Disease-modifying antirheumatic drugs (DMARDs). These can slow or stop pain, swelling, and joint and tissue damage. If NSAIDs don’t work, your doctor will try DMARDs. They may take longer to work.
- Immunosuppressants. If you can’t take a DMARD, you might get a type of drug called an immunosuppressant. These drugs curb your immune system, which is what’s causing the problem in an autoimmune condition like PsA. But they can also make it more likely that you’ll get an infection.
- UV light. Therapy with UVA light can ease skin symptoms in people who have severe psoriasis. But it may also raise your chances of skin cancer.
- Biologics. If immune suppression doesn't work, your doctor may prescribe a biologic. These are a newer type of DMARD. Rather than weaken your entire immune system, these medications block a protein that causes inflammation.
- Enzyme inhibitor. This works by blocking a certain enzyme, a kind of protein, called PDE-4. That helps slow other reactions that lead to inflammation.
- Steroids. These can help control inflammation, but doctors don’t use them often for PsA because they can make your skin rash worse. Doctors prescribe steroids only when you really need them. If you use them for a long time, you could have serious side effects such as brittle bones, weight gain, hypertension, and diabetes.
- Surgery. A severely damaged joint can be replaced with a new one made from metal and plastic.
Lifestyle changes and home remedies
Some things you do on your own can ease psoriatic arthritis symptoms:
- Keep a healthy weight. Carrying extra pounds puts more stress on your joints. It may also affect how well your medications work.
- Stop smoking. This is one of the best things you can do for your overall health.
- Limit alcohol. It can also affect how your treatments work.
- Exercise. It’s a great way to protect your joints and keep your weight in check. Stronger muscles can also support your joints. Low-impact exercises like swimming or walking are easier on them. Ask your doctor about an exercise plan.
- Try physical or occupational therapy. Your doctor might recommend that you see a specialist who can help you learn to manage your symptoms. This can involve exercises, body adjustments, hot and cold therapy, and tips for changing the way you do certain things. A physical or occupational therapist can also help you pick assistive devices like braces or splints to support your joints.
- Use acupuncture or massage therapy. These treatments are natural ways to ease pain and stiffness.
Psoriatic Arthritis Complications
PsA can make you more likely to have:
- A form of arthritis called gout
- Fatigue
- Obesity
- Metabolic syndrome, which may include high blood pressure, high cholesterol, and high blood sugar
- Fibromyalgia
- Depression and anxiety
Psoriatic Arthritis Flare Triggers
Certain things could trigger psoriatic arthritis, including:
Psoriatic Arthritis Outlook
There’s no cure for psoriatic arthritis. But treatment can ease your symptoms and may make them go away completely, known as remission. These periods can last for years.