Symptoms and Complications
Symptoms of psoriatic arthritis involve both skin and joint symptoms.
Skin symptoms include:
- scaly and silvery skin on the scalp, elbows, knees, or lower back that itch or burn
- fingernails or toenails that lift away from the skin or that are pitted with small holes (the nails can look similar to nails infected with the common nail fungus)
For more detailed information about skin symptoms, see the condition article on psoriasis.
Joint symptoms of psoriatic arthritis include pain, swelling, redness, and stiffness. Inflammation can occur in almost any joint but typically affects the joints of the fingers and toes, which may cause the fingers to swell and become sausage-shaped. Pain and swelling is also common where tendons and ligaments attach to bone (i.e., at the elbow or back of the heel) called enthesitis. Large joints are less commonly affected.
The patterns of joint involvement in psoriatic arthritis include:
- asymmetric with few joints involved
- symmetric rheumatoid-like pattern
- involvement of only the distal joints (finger and toe joints near the nails), which is very characteristic of psoriatic arthritis and uncommon in other conditions
- enthesitis (inflammation of the tendons and ligaments that attach to bone), which is common in psoriatic arthritis and can be very disabling; when severe, it can cause dactylitis
- dactylitis (the finger or toe looks sausage-like due to joint and tendon swelling), which is very characteristic of spondylopathies and more common
- back and sacroiliac joint predominantly involved
- a very rare joint-mutilating form
The most common pattern of inflammation is the asymmetrical type. Basically, this term is used to distinguish psoriatic arthritis from rheumatoid arthritis, in which inflammation in one joint is often mirrored on the other side of the body. Asymmetrical arthritis affects joints in an apparently random fashion. Someone might have pain in the left shoulder and right knee, for example. On the other hand, it may be that the left shoulder and left knee are affected. There's no set pattern.
Most people with psoriatic arthritis do not have back pain but if they do have inflammation in the spine, they usually find it worse at night and in the morning, and it eases with activity during the day.
In very severe psoriatic arthritis, the shape of the joint and the surrounding bone and tissue can change greatly. When severe arthritis causes disfiguration it's called arthritis mutilans. Rheumatoid arthritis is more likely than psoriatic arthritis to cause such severe damage.
Psoriatic arthritis inflammation tends to rise and fall in severity. The remissions (symptom-free periods) tend to be more complete than in rheumatoid arthritis; the arthritis may totally disappear during these periods. In some people, joint pain tends to rise and fall with the degree of skin inflammation, and in others, the two symptoms seem to occur entirely independent of one another.