Peyronie's disease was described by its namesake as involving "rosary beads of scar tissue [that] cause an upward curvature of the penis during erection." This problem, which affects about 1% of men (usually between ages 45 and 60), produces penile deformities and erectile dysfunction. Its cause is unknown, but it is thought to result from trauma or inflammation that produces a plaque of scar tissue. The result is a curvature of the erect penis that can interfere with sexual intercourse. While there are a number of medications commonly recommended for the problem, surgery is the only proven treatment. Surgery should be reserved for men with significant pain and sexual impairment and should not be undertaken until the disease has stabilized. In most cases Peyronie's disease begins gradually and progresses slowly over one to two years.