Peyronie's disease is caused by scar tissue in the penis, which makes the penis curve during an erection. For some men, this curving can cause pain and make sexual intercourse difficult or impossible.
The scar that causes this problem is composed of fibrous tissues that grow in the penile lining. This growth of fibrous tissue is most likely caused by injury to the penis.
Peyronie's disease usually affects men who are 50 and older. It rarely gets better on its own. But treatment usually is not needed. If Peyronie's disease causes pain or interferes with sexual function, treatment may include medicines or surgery.