There is no cure for psoriasis but the symptoms can be managed. It causes red, itchy scaly patches usually on the knees, elbows, trunk and scalp. It tends to go through cycles flaring for a few weeks or months and then subsiding or going into remission. The reason for psoriasis to develop is the increase in the turnover rate of skin cells. The new extra cells on the surface forms the red, silvery scaly patches. The symptoms include itching, burning, scaling, swollen and stiff joints, thickened, pitted or ridged nails. Dry, cracked skin can also cause blood coming out of the cracks. Treatment options include topical therapy with corticosteroids, Vitamin D analogues, retinoids, calcineurin inhibitors, salicylic acid, coal tar, Goeckerman therapy, and anthralin; light therapy that include sunlight, UVB broadband, UVB narrowband, Psoralen plus ultraviolet A (PUVA), and excimer laser; oral or injected medications that include steroids, retinoids, methotrexate, cyclosporine, biologics or other medications like thioguanine and hydroxyurea.