Priapism, a persistent, painful erection of the penis is an uncommon condition, but it is an emergency that requires immediate medical attention—if untreated, priapism may cause tissue damage that can result in erectile dysfunction.

Priapism occurs when the blood, blood vessels, or nerves within the penis change normal blood flow. Causes of this include:

  • Blood disorders, such as sickle cell anemia or leukemia
  • Prescription medications, such as Viagra or antidepressants
  • Alcohol and drug use
  • Traumatic injury to the penis

If you have an erection that lasts more than four hours or that is very painful, seek immediate medical attention.