Integumentary system (skin, hair, nails)
Although rare, psoriasis [3] is observed in people that have AS. The skin disease is autoimmune and can result in scaly patches of skin and red. The scaly patches can be seen anywhere in the body, but the knees, elbows, and scalp are more susceptible. In some cases, you may experience itchiness, stinging, tenderness, and burning. Your doctor may prescribe drugs to relieve symptoms.
Studies show that about 30 percent of people with psoriasis will experience complications like Psoriatic arthritis (PsA) [4]. This kind of arthritis can be seen in the knees, shoulders, hands, spine, and feet. If you experience pain in these areas, you should contact your doctor.