Psoriatic arthritis can affect different joints in the body, and it usually begins with the small joints of the hands and feet. It often starts with swelling and pain in the fingers and toes and can spread to larger joints, such as the knees, ankles, wrists, and elbows. It can also affect the spine, which may lead to stiffness and pain in the neck and lower back. Psoriatic arthritis can cause fatigue, swelling, and joint deformity, and it can also cause problems with the eyes, skin, and nails. Treatment may include anti-inflammatory medications, physical therapy, and lifestyle changes, such as getting adequate sleep, eating a healthy diet, and exercising regularly.