What is psoriatic arthritis?

Psoriatic arthritis is a chronic disease characterized by inflammation of the skin and joints Psoriatic arthritis is a systemic rheumatic disease that can also 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 features with several other arthritic conditions, such as ankylosising spondylitis, and arthritis associated with Crohn's disease and ulcerative colitis. All of these conditions can cause inflammation in the spine and other joints, and the eyes, skin, mouth, and various organs. In view of their similarities and tendency to cause inflammation of the spine, these conditions are collectively referred to as "spondyloarthropathies

The causes of psoriatic arthritis

The cause of psoriatic arthritis is currently unknown. A combination of genetic and immune as well as environmental factors are likely involved. In patients with psoriatic arthritis who have arthritis of the spine, a gene marker named HLA-B27 is frequently, but not always, found. It can develop at any time, but for most people it appears between the ages of 30 and 50. Psoriatic arthritis seems to affect men at a slightly higher percentage than women.

Symptoms of psoriatic arthritis

Psoriatic arthritis can develop slowly with mild symptoms, or it can develop quickly and be severe. Early recognition, diagnosis and treatment of psoriatic arthritis can help prevent or limit extensive joint damage that occurs in later stages of the disease. Generally, one or more of the following symptoms appears:

• Generalized fatigue
• Tenderness, pain and swelling over tendons
• Swollen fingers and toes
• Stiffness, pain, throbbing, swelling and tenderness in one or more joints
• A reduced range of motion
• Morning stiffness and tiredness Nail changes—for example, the nail separates from the nail bed and/or becomes pitted and mimics fungus infections
• Redness and pain of the eye, such as conjunctivitis
  

The disease can develop in a joint after an injury and may mimic a cartilage tear. The diagnosis of psoriatic arthritis may sometimes be made only after repeated episodes. Muscle or joint pain can occur without joint inflammation (swelling). Tendonitis and bursitis may be prominent features. Swelling of the fingers and toes can suggest a "sausage-like" appearance, known as dactylitis. Psoriatic arthritis usually affects the distal joints (those closest to the nail) in fingers or toes. The lower back, wrists, knees or ankles also may be affected

Types of psoriatic arthritis

There are five types of psoriatic arthritis: symmetric, asymmetric, distal interphalangeal predominant (DIP), spondylitis and arthritis mutilans.
Symmetric arthritis is much like rheumatoid arthritis but generally milder with less deformity. It usually affects multiple symmetric pairs of joints (occurs in the same joints on both sides of the body) and can be disabling.

Asymmetric arthritis can involve a few or many joints and does not occur in the same joints on both sides of the body. It can affect any joint, such as the knee, hip, ankle or wrist. The hands and feet may have enlarged "sausage" digits. The joints may also be warm, tender and red. Individuals may experience periodic joint pain which is usually responsive to medical therapy. This form is generally mild, although some people might develop disabling disease.

Distal interphalangeal predominant (DIP) although the "classic" type, occurs in only about 5 percent of people with psoriatic arthritis. Primarily, it involves the distal joints of the fingers and toes (the joint closest to the nail). Sometimes it is confused with osteoarthritis, but nail changes are usually prominent.

Spondylitis is inflammation of the the spinal column. In about 5 percent of individuals with psoriatic arthritis, spondylitis is the predominant symptom. Inflammation with stiffness of the neck, lower back, sacroiliac or spinal vertebrae are common symptoms in a larger number of patients, making motion painful and difficult. Peripheral disease can be present in the hands, arms, hips, legs and feet.

Arthritis mutilans is a severe, deforming and destructive arthritis that affects fewer than 5 percent of people with psoriatic arthritis. It principally affects the small joints of the hands and feet, though there is frequently associated neck or lower back pain.