A study of 26,000 South American Indians did not reveal a single case of psoriasis. However, men are thought to be more likely to experience the ocular disease. The skin almost always is affected before the eyes. The nonocular symptoms are related to rash and psoriatic arthritis. The rash can be uncomfortable or even painful.
Psoriatic arthritis can cause stiffness, pain, throbbing, swelling, or tenderness of the joints.
The distal joints, such as the fingers, toes, wrists, knees, and ankles, are affected most often. The most common ocular symptoms are redness and tearing due to conjunctivitis or blepharitis. Blepharitis is the most common ocular finding in psoriasis. Erythema, edema, and psoriatic plaques may develop, and they can result in madarosis, cicatricial ectropion, trichiasis, and even loss of the lid tissue. A chronic nonspecific conjunctivitis is fairly common.