What are psoriatic arthritis symptoms and signs?
In most patients, the psoriasis precedes the 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 and few joints, spondylitis, distal interphalangeal joints, and arthritis mutilans.
The 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. There is usually loss of range of motion of the involved joints. Sometimes, joint inflammation in the fingers or toes can cause swelling of the entire digit, giving them the appearance of a "sausage." Joint stiffness is a common symptom and is typically worse early in the morning. Less commonly, psoriatic arthritis may involve many joints of the body in a symmetrical fashion, mimicking the pattern seen in rheumatoid arthritis. Psoriatic arthritis can also cause inflammation of the spine (spondylitis) and the sacrum, causing 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. A very destructive, though less common, form of arthritis called "mutilans" can cause rapid damage to the joints. Fortunately, this form of arthritis is rare in patients with psoriatic arthritis.
Patients with psoriatic arthritis can also develop inflammation of the tendons (tendinitis), tendon insertion points on bone (enthesitis), and around 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 of the cartilage that links the ribs to the breastbone (sternum) can cause chest pain, as seen in costochondritis.
Aside from arthritis and spondylitis, psoriatic arthritis can cause fatigue and inflammation in other organs, such as the eyes, lungs, and aorta. Inflammation in the colored portion of the eye (iris) causes iritis, a painful health condition that can be aggravated by bright light as the iris opens and closes the opening of the pupil. 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, as well as shortness of breath. Inflammation of the aorta (aortitis) can cause leakage of 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 fingernails and toenails of 80% of patients with psoriatic arthritis. 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. In fact, 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.