Psoriatic Arthritis

  • Psoriatic arthritis is a chronic disease characterized by a form of inflammation of the skin (psoriasis) and joints (inflammatory arthritis).
  • Some 15%-25% of people with psoriasis also develop inflammation of joints (psoriatic arthritis).
  • The first appearance of skin disease (psoriasis) can be separated from the onset of joint disease (arthritis) by years.
  • Psoriatic arthritis symptoms and signs include
    • low back pain,
    • conjunctivitis,
    • reduced range of motion,
    • swollen joints,
    • nail pitting,
    • joint pain and morning stiffness,
    • foot pain,
    • fatigue,
    • swelling of the toes and fingers (dactylitis).
  • Psoriatic arthritis belongs to a group of arthritis conditions that can cause inflammation of the spine (spondyloarthropathies).
  • People with psoriatic arthritis can develop inflammation of tendons, cartilage, eyes, lung lining, and, rarely, the aorta.
  • Psoriatic arthritis’s arthritis is treated independently of psoriasis, exercise, ice applications, medications, and surgery.

 Psoriatic arthritis is a chronic autoimmune disease characterized by a form of inflammation of the skin (psoriasis) and joints (inflammatory arthritis). Psoriasis is a common skin condition affecting 2% of the Caucasian population in the United States. Signs and symptoms include patchy, raised, red areas of skin inflammation with scaling. Psoriasis often affects the elbows and knees’ tips, the scalp and ears, the navel, and genital areas or anus. Approximately 15%-25% of patients who have psoriasis also develop an associated inflammation of their joints. Patients who have inflammatory arthritis and psoriasis are diagnosed as having psoriatic arthritis.

The onset of psoriatic arthritis generally occurs in the fourth and fifth decades of life. Males and females are affected equally. The skin disease (psoriasis) and the joint disease (arthritis) often appear separately. The skin disease precedes arthritis in nearly 80% of people. However, arthritis may precede psoriasis in up to 15% of patients. In some patients, psoriatic arthritis diagnosis can be difficult if arthritis precedes psoriasis by many years. Some patients have had arthritis for over 20 years before psoriasis eventually appears! Conversely, patients can have psoriasis for more than 20 decades before developing arthritis, leading to psoriatic arthritis’s ultimate diagnosis.

Psoriatic arthritis is a systemic rheumatic disease that also can cause inflammation in body tissues away from the joints other than the skin, such as in the eyes, heart, lungs, and kidneys. Psoriatic arthritis shares many symptoms with several other arthritic conditions, such as ankylosing spondylitis, reactive arthritis, and arthritis associated with Crohn’s disease and ulcerative colitis. These health conditions can cause inflammation in the spine and other joints, and the eyes, skin, mouth, and various organs. Given their similarities and tendency to cause inflammation of the spine, these health conditions are collectively referred to as “spondyloarthropathies.”

Symptoms and Signs of Psoriatic Arthritis

Psoriatic arthritis symptoms and signs include

  • joint aches and stiffness,
  • joint swelling,
  • joint warmth and redness,
  • joint pain and tenderness,
  • loss of range of motion of the affected joints.

If the spine is affected, there can be pain and stiffness in the low back, buttocks, neck, and upper back. Tendons can also become inflamed. If Achilles tendonitis is present, other symptoms can include limping, pain with walking, and climbing stairs. Enthesitis, or the inflammation of the areas at which ligaments and tendons meet the bone, is often a feature of psoriatic arthritis.

Causes of Psoriatic Arthritis

The cause of psoriatic arthritis is currently unknown. A combination of genetic, immune, and environmental factors is likely involved. In patients with psoriatic arthritis who have arthritis of the spine, a blood test gene marker called HLA-B27 is found in about 50%. Several other genes have also been found to be more common in patients with psoriatic arthritis. Specific changes in the immune system may also be significant in the development of psoriatic arthritis. For example, the decline in the number of immune cells called helper T cells in people with AIDS (HIV infection) may play a role in the development and progression of psoriasis in these patients. Researchers are investigating the importance of infectious agents and other environmental factors in the cause of psoriatic arthritis.

Risk factors of Psoriatic Arthritis

The primary risk factor for developing psoriatic arthritis has a family member with psoriasis. This relationship has been recognized as so significant that it is used as a valuable part of the doctor’s health history to aid in the diagnosis of psoriatic arthritis. It might be that stressful life situations could affect the immune system, allowing for the expression and or exacerbation of psoriatic arthritis. However, precisely how these emotional issues are related to psoriatic arthritis has not been established.

Different types of Psoriatic Arthritis

The type of psoriatic arthritis depends on the distribution of the joints affected. Accordingly, there are five types of psoriatic arthritis: symmetrical polyarthritis (both sides of the body), asymmetric oligoarticular, spondylitis, distal interphalangeal joints, and arthritis mutilans.

Symptoms and Signs of Psoriatic Arthritis

In most patients, psoriasis precedes arthritis by months to years. There can be tiny pitting nail changes of the finger and toenails. The type of psoriatic arthritis depends on the distribution of the joints affected. Accordingly, there are five types of psoriatic arthritis: symmetrical, asymmetric, few joints, spondylitis, distal interphalangeal joints, and arthritis mutilans.

Arthritis frequently involves the knees, ankles, and joints in the feet. Usually, only a few joints are inflamed at a time. The inflamed joints become painful, stiff, swollen, hot, tender, and red during flare-ups. There is usually a loss of range of motion of the involved joints. Sometimes, psoriatic joint inflammation in the fingers or toes can cause swelling of the entire digit (dactylitis), giving them a sausage-like appearance. Joint stiffness is a common arthritis symptom and is typically worse early in the morning. Less commonly, psoriatic arthritis may involve many joints of the body symmetrically, mimicking the pattern seen in rheumatoid arthritis. Psoriatic arthritis can also cause inflammation of the spine (spondylitis) and the sacrum (sacroiliitis), causing other symptoms like pain and stiffness in the low back, buttocks, neck, and upper back. Occasionally, psoriatic arthritis involves the small joints at the ends of the fingers. Though less common, a form of arthritis called “mutilans” can cause rapid joint damage. Fortunately, this form of arthritis is rare in patients with psoriatic arthritis.

Patients with psoriatic arthritis can also develop the tendons (tendinitis), tendon insertion points on the bone (enthesitis, inflammation of the entheses), and cartilage. Inflammation of the tendon behind the heel causes Achilles tendinitis, leading to pain with walking and climbing stairs. Inflammation of the chest wall and the cartilage that links the ribs to the breastbone (sternum) can cause chest pain, as seen in costochondritis.

In most patients, psoriatic arthritis causes swelling and inflammation of the fingers and pitting and ridges in the fingernails.

Aside from arthritis and spondylitis, psoriatic arthritis can cause symptoms like fatigue and inflammation in other organs, such as the eyes, lungs, and aorta. Inflammation in the colored portion of the eye (iris) causes iritis. This painful health condition can be aggravated by bright light as the iris opens and closes the pupil’s opening. Corticosteroids injected directly into the eyes are sometimes necessary to decrease inflammation and prevent blindness. Inflammation in and around the lungs (pleuritis) causes chest pain, especially with deep breathing as the lungs expand against the inflamed areas and shortness of breath. Inflammation of the aorta (aortitis) can leak the aortic valves, leading to heart failure and shortness of breath.

Acne and nail changes are symptoms commonly seen in psoriatic arthritis. Pitting and ridges are seen in the fingernails and toenails of 80% of patients with psoriatic arthritis. Onycholysis, or separation of the nail bed, may also occur. Interestingly, these characteristic nail changes are observed in only a minority of psoriasis patients who do not have arthritis. Acne has been noted to occur in higher frequency in patients with psoriatic arthritis. A syndrome exists that features inflammation of the joint lining (synovitis), acne, pustules on the feet or palms, thickened and inflamed bone (hyperostosis), and bone inflammation (osteitis). This syndrome is, therefore, named by the eponym SAPHO syndrome.