An erection of the penis that lasts too long, most often without sexual arousal.

Priapism can cause a full or partial erection. It can happen on its own. Or certain antidepressants or erectile dysfunction medicines can cause it. Priapism is common in people with sickle cell disease.

Symptoms include an erection lasting more than four hours or off and on for several hours. The penis can be painful or tender.

Prompt treatment is needed. Options include draining blood from the penis and medicine to restrict blood flow to the penis.