Itchy knees need to be alert to degenerative joint disease and autoimmune disease. 1. Degenerative lesions of the knee joint: that is, osteoarthropathy of the knee joint, when the knee degeneration may cause the formation of the knee joint’s bone cumbersome, synovial membrane hyperplasia and other pathologic changes, resulting in the joint in the process of movement of the joint impact or friction caused by the increase in the joint damage, the body in the process of repairing the damaged parts, the knee itching symptoms may occur. 2. Autoimmune diseases: patients with autoimmune diseases may accumulate in the knee joints, causing metabolic reactions in the joints, resulting in the deposition of metabolites, immune complexes and other substances in the joints, stimulating the surrounding nerve roots, and symptoms of knee itching may also occur, such as gouty knee osteoarthritis, rheumatic knee osteoarthritis and other common diseases. Itchy knees may also have other causes, including skin allergic diseases, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.