The inability to completely retract the penis into the preputial cavity usually occurs after erection. It is seen most often after semen collection or coitus. The skin at the preputial orifice becomes inverted, trapping the extruded penis and impairing venous drainage. Other causes of paraphimosis include mild phimosis, foreign objects around the penis, a constricting band of hair at the preputial orifice, or trauma. Paraphimosis is easily differentiated from priapism, congenitally shortened prepuce, congenital deformity of the os penis, or paralysis of the retractor penis muscles on the basis of physical examination and palpation.
Paraphimosis is a medical emergency. The exposed penis quickly becomes edematous because its venous drainage is compromised. With continued exposure, it becomes dry and painful. If untreated, ulceration, ischemic necrosis, or gangrene may develop. If recognized early, before severe edema and pain develop, paraphimosis is easily treated. Treatment consists of gentle cleansing and lubrication of the exposed penis. The penis is replaced inside the prepuce by first sliding the prepuce in a posterior direction, extruding the penis further. This everts the skin at the preputial orifice; usually the prepuce then slides easily over the penis. The edema resolves promptly once circulation is restored.
If the everted prepuce does not slide over the edematous, exposed penis, a cold compress may be applied with gentle digital pressure to act as a pressure bandage. Application of hypertonic solutions may also help reduce swelling. With paraphimosis due to other causes, or of longer duration, sedation or general anesthesia is required. It may be necessary to incise the preputial skin to thoroughly examine the preputial cavity, remove restricting material, and relieve venous obstruction. The penis is then replaced in the preputial cavity, and the incision is closed. If the urethra has been damaged, temporary placement of a closed-system indwelling urinary catheter may be needed to prevent stricture formation. If necrosis or gangrene is severe, amputation of the penis and prepuce and castration may be necessary.
Last full review/revision July 2011 by Cheri A. Johnson, DVM, MS, DACVIM (Small Animal)