Psoriatic arthritis is an inflammatory condition that affects the joints of children and adults with psoriasis. Psoriasis is a skin condition that causes patches of thick, red skin to form on certain areas of your body. Not everyone with psoriasis develops psoriatic arthritis, but everyone with psoriatic arthritis has psoriasis.
Most people develop the skin signs of psoriasis first and are later diagnosed with psoriatic arthritis. Joint pain in people with psoriatic arthritis can range from mild to severe. Many experience changing signs and symptoms as the disease continues.
Many definitions of psoriatic arthritis exist, which makes it hard to estimate how many people have the disease. About 10 percent to 15 percent of people with psoriasis eventually develop psoriatic arthritis. While no cure for psoriatic arthritis exists, doctors work to control your signs and symptoms and prevent damage to your joints.
Psoriasis is a skin condition marked by a rapid buildup of rough, dry, dead skin cells that form thick scales. Arthritis causes pain and stiffness in your joints. Both are autoimmune problems — disorders that occur when your body's immune system, which normally fights harmful organisms such as viruses and bacteria, begins to attack healthy cells and tissue. The abnormal immune response causes inflammation in your joints as well as the overproduction of skin cells.
It's not entirely clear why the immune system turns on itself, but it seems likely that both genetic and environmental factors play a role. Many people with psoriatic arthritis have a close relative, such as a parent or sibling, with the disease, and researchers have discovered certain gene mutations that appear to be associated with psoriatic arthritis.
Having a genetic mutation doesn't necessarily mean you'll develop psoriatic arthritis, but it does mean you have a greater tendency to do so than other people do. Physical trauma or something in the environment — such as a viral or bacterial infection — may eventually trigger psoriatic arthritis in people who have an inherited tendency.
Risk Factor :
Having psoriasis is the single greatest risk factor for psoriatic arthritis. In particular, people who experience psoriasis lesions on their nails are more likely to develop psoriatic arthritis.
Other risk factors include :
- Your family history. Many people with psoriatic arthritis have a close relative with the disease.
- Your age. Although anyone can develop psoriatic arthritis, it occurs most often in adults between the ages of 30 and 50.
- Your sex. In general, psoriatic arthritis affects men and women equally, but DIP and spondylitis are more likely to affect men, whereas symmetric arthritis occurs more often in women.
When to seek medical advice :
If you have persistent discomfort and swelling in multiple joints, see your doctor. He or she can work with you to develop a pain management and treatment plan.
Psoriatic arthritis may affect one joint or many. Signs and symptoms of psoriatic arthritis include :
- Pain in affected joints
- Swollen joints
- Joints that are warm to the touch
Patterns of joint pain in psoriatic arthritis
Doctors have identified five patterns in which psoriatic arthritis typically occurs. Most people move from one pattern of psoriatic arthritis to another throughout their lives. Treatment usually varies based on the pattern of joint involvement you experience. Patterns of psoriatic arthritis include :
- Pain in joints on one side of your body. The mildest form of psoriatic arthritis, called asymmetric psoriatic arthritis, usually affects joints on only one side of your body or different joints on each side — including those in your hip, knee, ankle or wrist. One to three joints are generally involved, and they're often tender and red. When asymmetric arthritis occurs in your hands and feet, swelling and inflammation in the tendons can cause your fingers and toes to resemble small sausages (dactylitis).
- Pain in joints on both sides of your body. Symmetric psoriatic arthritis usually affects four or more of the same joints on both sides of your body. More women than men have symmetric psoriatic arthritis, and psoriasis associated with this condition tends to be severe.
- Pain in your finger joints. Distal interphalangeal (DIP) joint predominant psoriatic arthritis is rare and occurs mostly in men. DIP affects the small joints closest to the nails (distal joints) in the fingers and toes.
- Pain in your spine. This form of psoriatic arthritis, called spondylitis, can cause inflammation in your spine as well as stiffness and inflammation in your neck, lower back or sacroiliac joints. Inflammation can also occur where ligaments and tendons attach to your spine. As the disease progresses, movement tends to become increasingly painful and difficult.
- Destructive arthritis. A small percentage of people with psoriatic arthritis have arthritis mutilans — a severe, painful and disabling form of the disease. Over time, arthritis mutilans destroys the small bones in the hands, especially the fingers, leading to permanent deformity and disability.
No single test can confirm a diagnosis of psoriatic arthritis. Your doctor will assess your signs and symptoms and work to rule out other causes of joint pain, such as osteoarthritis and rheumatoid arthritis. Tests that help to distinguish psoriatic arthritis from other conditions include :
- X-rays. These can help pinpoint changes in the joints that occur in psoriatic arthritis but not in other arthritic conditions.
- Joint fluid test. In this test, your doctor removes a small sample of fluid from one of your joints — often the knee — for analysis in a laboratory. Uric acid crystals in your joint fluid may indicate that you have gout, rather than psoriatic arthritis.
- Sed rate. This blood test checks your erythrocyte sedimentation rate (ESR), commonly known as the sed rate, by measuring how far from the top of a glass tube your red blood cells fall in a given time. Generally, the blood cells fall farther — that is, the sed rate increases — when inflammation is present. But because many conditions can cause inflammation in the body, including many forms of arthritis and other rheumatic diseases, an elevated sed rate alone can't confirm the presence of psoriatic arthritis.
- Rheumatoid factor (RF). RF is an antibody — a protein made by the immune system — that's often present in the blood of people with rheumatoid arthritis, but not in the blood of people with psoriatic arthritis. For that reason, this test can help your doctor distinguish between the two conditions.
Most people are diagnosed with psoriasis before they begin experiencing the pain of psoriatic arthritis. In a minority of cases, people experience the joint pain of psoriatic arthritis before they have signs and symptoms of psoriasis. In these cases, if you have joint pain that suggests psoriatic arthritis, your doctor will conduct a careful examination of your skin to look for any signs and symptoms of psoriasis.
Psoriatic arthritis can be debilitating and painful, making it difficult to go about your daily routine. Despite medications, psoriatic arthritis can cause erosion in your joints.
Doctors have difficulty determining who will experience the most destructive forms of this disease and who won't. In general, people diagnosed with psoriatic arthritis at a younger age, women and those with sudden-onset joint pain are more likely to develop severe psoriatic arthritis.
No cure exists for psoriatic arthritis. Your doctor works to control inflammation in your affected joints in order to prevent joint pain and disability. This is usually accomplished with medications and, rarely, surgery.
Medications commonly used to treat psoriatic arthritis include :
Nonsteroidal anti-inflammatory drugs (NSAIDs). Drugs such as aspirin and ibuprofen (Advil, Motrin, others) may help control pain, swelling and morning stiffness. Prescription NSAIDs provide higher potencies than do over-the-counter drugs. But all NSAIDs can irritate your stomach and intestine, and long-term use can lead to ulcers and gastrointestinal bleeding.
Other potential side effects include damage to your kidneys, fluid retention and heart failure. In addition, NSAIDs may worsen skin problems. Still, these medications may be a good option for people with minor joint pain and stiffness.
- Corticosteroids. If you have mild psoriatic arthritis, your doctor might recommend corticosteroids to control infrequent joint pain flares. Corticosteroids can be taken orally, or they can be injected directly into aching joints. Corticosteroid injections provide almost immediate relief and improve range of motion — sometimes for months. But because injected steroids can cause damage, their use is usually limited.
- Disease-modifying antirheumatic drugs (DMARDs). Rather than just reducing pain and inflammation, this class of drugs helps limit the amount of joint damage that occurs in psoriatic arthritis. But because DMARDs act slowly, you may not notice the effects for weeks or even months. For that reason, your doctor may prescribe a pain reliever, such as aspirin, in addition to a DMARD. Examples of DMARDs include sulfasalazine (Azulfidine), hydroxychloroquine (Plaquenil) and methotrexate.
- Immunosuppressant medications. These medications act to suppress the immune system, which normally protects the body from harmful organisms, but which attacks healthy tissue in people with psoriatic arthritis. Commonly used immunosuppressants include azathioprine (Imuran), cyclosporine (Sandimmune, Neoral) and leflunomide (Arava).
Immunosuppressants can have potentially dangerous side effects and usually are used in only the most severe cases of psoriatic arthritis. Because they suppress the immune system, all such drugs can lead to anemia and an increased risk of serious infection. And many of them can cause liver and kidney problems.
- TNF-alpha inhibitors. Your doctor may recommend tumor necrosis factor-alpha (TNF-alpha) inhibitors if you have severe psoriatic arthritis. These drugs block a protein that causes inflammation in some types of arthritis. Drugs in this category include etanercept (Enbrel), adalimumab (Humira) and infliximab (Remicade). TNF-alpha inhibitors can help manage signs and symptoms of psoriasis, as well. However, these drugs carry a risk of side effects, including serious infections.
Although surgery is rarely performed for psoriatic arthritis, your doctor may recommend some form of joint operation when other treatments fail to relieve your symptoms. Surgeons use various procedures to ease pain and restore mobility. Because these operations pose some risks, be sure you thoroughly discuss your options with your doctor.