Priapism causes abnormally persistent erections not related to sexual stimulation. Priapism symptoms may vary depending on the type of priapism. There are two main types: ischemic and nonischemic priapism.

Ischemic priapism

Ischemic, also called low-flow, priapism is the result of blood not being able to leave the penis. It's the more common type of priapism. Signs and symptoms include:

  • Unwanted erection lasting more than four hours
  • Unwanted erection off and on for several hours (stuttering priapism)
  • Rigid penile shaft, but usually soft tip of penis (glans)
  • Usually painful or tender penis

Nonischemic priapism

Nonischemic, or high-flow, priapism occurs when too much blood flows into the penis. Nonischemic priapism is usually painless. Signs and symptoms include:

  • Unwanted erection lasting at least four hours
  • Erect but not rigid penile shaft

When to see a doctor

If you have an erection lasting longer than four hours, go to the emergency room. If you experience a painful, persistent erection that resolves on its own in less than four hours, see your doctor. You may need treatment to prevent further episodes.

Jun. 15, 2013