Psoriatic Arthritis

What is psoriatic arthritis?

Psoriasis and psoriatic arthritis are autoimmune conditions. An autoimmune condition occurs when the body's immune system mistakenly sends inflammation to normal tissue/structures. In skin psoriasis, the inflammation is mistakenly directed toward the skin. In psoriatic arthritis, the inflammation is directed toward the joints, similar to rheumatoid arthritis, causing inflammation (swelling, redness, pain and stiffness) and damage. Like any autoimmune condition, psoriasis and psoriatic arthritis can present across a broad spectrum from mild to severe disease. There is a weak relationship between the severity of skin disease and arthritic involvement. Some patients may have severe skin disease and no arthritis and some arthritis patients may have only minimal skin disease.

Psoriatic arthritis can affect any joint in the body, and it may affect just one joint, several joints or multiple joints. For example, it may affect one or both knees. Affected fingers and toes can resemble swollen sausages, a condition often referred to as dactylitis. Finger and toe nails also may be affected with thickening or nail pitting. Psoriatic arthritis in the spine, called spondylitis, causes pain in the back or neck, and difficulty bending. Psoriatic arthritis also can cause tender spots where tendons and ligaments join onto bones. This condition, called enthesitis, can result in pain at the back of the heel, the sole of the foot, around the elbows or in other areas. Enthesitis is one of the characteristic features of psoriatic arthritis.

Recent research suggests that persistent inflammation from psoriatic arthritis causes joint damage later, so early accurate diagnosis is essential. Fortunately, treatments are available and effective for most people.

Symptoms and causes

Symptoms

Both psoriatic arthritis and psoriasis are chronic diseases that get worse over time, but you may have periods when your symptoms improve or go into remission alternating with times when symptoms become worse.

Psoriatic arthritis can affect joints on just one side or on both sides of your body. The signs and symptoms of psoriatic arthritis often resemble those of rheumatoid arthritis. Both diseases cause joints to become painful, swollen and warm to the touch.

However, psoriatic arthritis is more likely to also cause:

  • Swollen fingers and toes. Psoriatic arthritis can cause a painful, sausage-like swelling of your fingers and toes. You may also develop swelling and deformities in your hands and feet before having significant joint symptoms.
  • Foot pain. Psoriatic arthritis can also cause pain at the points where tendons and ligaments attach to your bones — especially at the back of your heel (Achilles tendinitis) or in the sole of your foot (plantar fasciitis).
  • Lower back pain. Some people develop a condition called spondylitis as a result of psoriatic arthritis. Spondylitis mainly causes inflammation of the joints between the vertebrae of your spine and in the joints between your spine and pelvis (sacroiliitis).

Causes

Psoriatic arthritis occurs when your body's immune system begins to attack healthy cells and tissue. The abnormal immune response causes inflammation in your joints as well as overproduction of skin cells.

It's not entirely clear why the immune system turns on healthy tissue, but it seems likely that both genetic, and environmental factors play a role. Many people with psoriatic arthritis have a family history of either psoriasis or psoriatic arthritis. Researchers have discovered certain genetic markers that appear to be associated with psoriatic arthritis.

Physical trauma or something in the environment — such as a viral or bacterial infection — may trigger psoriatic arthritis in people with an inherited tendency.

Risk factors

  • Having psoriasis is the single greatest risk factor for developing psoriatic arthritis. People who have psoriasis lesions on their nails are especially likely to develop psoriatic arthritis.
  • Your family history. Many people with psoriatic arthritis have a parent or a sibling with the disease.
  • Your age. Although anyone can develop psoriatic arthritis, it occurs most often in adults between the ages of 30 and 50.

Complications

A small percentage of people with psoriatic arthritis develop arthritis mutilans — a severe, painful and disabling form of the disease. Over time, arthritis mutilans destroys the small bones in your hands, especially the fingers, leading to permanent deformity and disability.

People who have psoriatic arthritis sometimes also develop eye problems such as pinkeye (conjunctivitis) or uveitis, which can cause painful, reddened eyes and blurred vision. They also are at higher risk of cardiovascular disease.

Diagnosis

During the exam, your doctor may:

  • Closely examine your joints for signs of swelling or tenderness
  • Check your fingernails for pitting, flaking and other abnormalities
  • Press on the soles of your feet and around your heels to find tender areas

No single test can confirm a diagnosis of psoriatic arthritis. But some types of tests can rule out other causes of joint pain, such as rheumatoid arthritis or gout.

Imaging tests

  • X-rays. Plain X-rays can help pinpoint changes in the joints that occur in psoriatic arthritis but not in other arthritic conditions.
  • Magnetic resonance imaging (MRI). MRI utilizes radio waves and a strong magnetic field to produce very detailed images of both hard and soft tissues in your body. This type of imaging test may be used to check for problems with the tendons and ligaments in your feet and lower back.

Laboratory tests

  • Rheumatoid factor (RF). RF is an antibody that's often present in the blood of people with rheumatoid arthritis, but it's not usually in the blood of people with psoriatic arthritis. For that reason, this test can help your doctor distinguish between the two conditions.
  • Joint fluid test. Using a needle, your doctor can remove a small sample of fluid from one of your affected joints — often the knee. Uric acid crystals in your joint fluid may indicate that you have gout rather than psoriatic arthritis.
  • The presence of an HLA-B27 genetic marker is associated with psoriatic arthritis but it is not diagnostic. Occasionally skin biopsies (small samples of skin removed for analysis) are needed to confirm the psoriasis.

Treatment

Medications are used to reduce inflammation caused by arthritis reducing pain, swelling and stiffness. Many of the medications suppress the immune system and lead to a potential increase risk of infections. The majority of the medications treat both the skin and joint disease, but some medications may work better for one compared to the other. Non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin or Advil) or naproxen (Aleve) are the initial treatment for very mild arthritis. These do not help skin psoriasis. Non-steroidal anti-inflammatory medications have not been proven to stop damage caused by more aggressive/severe psoriatic arthritis.

If the arthritis does not respond, disease modifying anti-rheumatic drugs (DMARDs)may be prescribed. These include sulfasalazine (Azulfidine), methotrexate (Rheumatrex, Trexall, Otrexup, Rasuvo),  and leflunomide (Arava). Although these medications can be very helpful with improving both skin and joint disease, they have not been proven to stop the progression of joint damage radiographically. If joint damage is present at time of diagnosis, consider increasing therapy to include biologic therapy. Older DMARD therapies that are less commonly used today due to the development of biologic therapies are sulfasalazine (Azulfidine), Azathioprine (Imuran), and the anti-malarial drug hydroxychloroquine (Plaquenil). It was once thought Hydroxychloraquine would flare skin psoriasis but this has not been proven.

Newer biologic therapy has been developed to block molecules and/or their receptors leading to decreased inflammation. Many of these medications are given by injections at home or by an infusion at the doctor’s office. These medications suppress the immune system to a great degree compared to the DMARDs. They have been proven to stop joint damage as well as pain and swelling in moderate to severe psoriatic arthritis. They are very good at clearing skin psoriasis. The biologic therapies include anti-tumor necrosis factor (anti-TNF) drugs such as adalimumab (Humira), etanercept (Enbrel), golimumab (Simponi), certolizumab (Cimzia) and infliximab (Remicade) are also available and can help the arthritis as well as the skin psoriasis.

Other biologic therapies include ustekinumab (Stelara) which blocks two proteins IL-12 and IL-23. This is given as a subcutaneous injection every 3 months. The newest biologic to be FDA approved (in January of 2016) is secukinumab (Cosentyx) which blocks IL-17 to reduce inflammation. It is given by a subcutaneous injection and has been approved for treatment of both skin psoriasis and psoriatic arthritis. Apremilast (Otezla) is a phosphodiesterase 4 inhibitor that helps stop inflammation. It is an oral pill taken twice daily. Unlike the other treatments, it is not thought to suppress the immune system causing increased risk on infections. Stomach upset, headache, weight loss and worsening depression are potential side effects.

For swollen joints, corticosteroid injections can be useful. Surgery can be helpful to repair or replace badly damaged joints.

Broader health impact of psoriatic arthritis

The impact of psoriatic arthritis depends on the joints involved and the severity of symptoms. Ocular inflammation, including uveitis and conjunctivitis, occurs in some patients with psoriatic arthritis. Some psoriatic arthritis patients also experience mood changes. Treating the arthritis and reducing the levels of inflammation helps with these problems. People with psoriasis are slightly more likely to develop high blood pressure, high cholesterol, obesity or diabetes. Maintaining a healthy weight and treating high blood pressure and cholesterol are also important aspects of treatment. - See more at: http://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Psoriatic-Arthritis#sthash.CmVuVT9t.dpuf

Living with psoriatic arthritis

Many people with arthritis develop stiff joints and muscle weakness due to lack of use. Proper exercise is very important to improve overall health and keep joints flexible. This can be quite simple. Walking is an excellent way to get exercise. A walking aid or shoe inserts will help to avoid undue stress on feet, ankles, or knees affected by arthritis. An exercise bike provides another good option, as well as yoga and stretching exercises to help with relaxation.

Some people with arthritis find it easier to move in water. If this is the case, swimming or walking laps in the pool offers activity without stressing joints. Many people with psoriatic arthritis also benefit from physical and occupational therapy to strengthen muscles, protect joints from further damage, and increase flexibility.

See more at: http://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Psoriatic-Arthritis

Links

http://www.mayoclinic.org/diseases-conditions/psoriatic-arthritis/home/ovc-20233896

http://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Psoriatic-Arthritis