Paraphimosis occurs when the foreskin becomes trapped behind the glans penis and is unable to return to its natural position inside the preputial cavity (sheath) leaving the glans exposed.

Clinical Signs

May see the following:

  • Penis stuck outside of the preputial cavity (sheath). Swelling and balanitis (inflammation of glans penis) may also be present.
  • Band of retracted skin behind the head of penis, may also be swollen and tight.
  • Rat frantically licks the penis.
  • Rat showing signs of sensitivity and pain when the area is examined or touched.
  • A redness and later darkening of tissue.
  • Rat usually has difficulty urinating.

*Note: for additional information on recognizing various signs of pain or discomfort refer to: Signs of Pain In Rats.


Paraphimosis results when the foreskin (sheath) is either retracted behind the glans and becomes strictured, or becomes folded (rolled). This constriction can cause blood flow from the penis to be blocked or compromised. When this happens, swelling and inflammation of the glans penis, foreskin (sheath), or both, result. The increased size due to constriction and swelling then prevents the penis from being returned to its natural position within the sheath.

Paraphimosis can be a result of phimosis (inability to retract the prepuce over the glans penis), injury (trauma), infection, or congenital issues such as an abnormally shortened prepuce or an abnormally long penis.
There have been reports of paraphimosis occurring after severe dehydration and/or starvation but this has not been confirmed within the scientific community.

Other causes that can lead to paraphimosis are:

  • Poor hygiene
  • Chemical irritants (soaps)
  • Conditions that result in edema (swelling) such as CHF, or nephrosis
  • Bacterial infections (primarily anaerobic infections)
  • Obesity
  • Diabetes

Paraphimosis can be a true emergency. If left untreated, the impaired lack of blood flow to the glans can result in urinary retention, infection, and necrosis. It is important to seek help from a veterinarian as soon as possible. Prognosis is favorable with prompt treatment.


Case History of Paraphimosis

  • Fig 1: Paraphimosis in a 7-week-old rat


Care should be taken to take a full health history and perform a full examination.
Visual and manual examination of the penis will show a penis that is enlarged and trapped outside of the sheath. The penis may present as a reddened, round ball of flesh.

Paraphimosis should not be confused with priapism (an erection that doesn’t subside) or phimosis (constricted foreskin that can trap the penis inside and prevent it from being able to emerge from the sheath). If the condition returns steps should be taken to determine if there is an underlying problem.


The main goal of each method is to return the penis to its naturally occurring position inside the preputial cavity (sheath). If recognized early, before pain and severe edema develop, paraphimosis can be resolved easily with non invasive treatment

Noninvasive treatment methods

  • Very gently retract sheath, gently cleanse with warm water and mild soap to remove any secretions that may have built up, rinse gently, and pat dry.
  • Apply a lubricant (e.g., olive oil, canola oil, vegetable oil, peanut oil) to the penis to help with gentle manual reinsertion and prevent tissue from drying out. *Note: may repeat application of lubricant/ointment if the penis remains exposed out of the sheath when checking the rat a couple of hours after the first application.
  • The use of an antibiotic ointment (e.g., Polysporin or Bacitracin) may be applied to help control infection if present.
  • Manual insertion may be accomplished by gently extruding the penis further out, lubricating the shaft, and gently pushing it back into the preputial cavity.
  • Reduction of swelling to allow the penis to naturally slide back in.
    • To reduce swelling you can:
      • Sprinkle fine granulated sugar on the penis and surrounding area (Gradient osmosis).
      • Apply a small wrapped ice pack to the penis for short intervals.
      • Apply a steroidal cream.

Mildly invasive treatment

  • Puncture technique (under anesthesia) with the use of hyaluronidase (degradation of hyaluronic acid permits diffusion of trapped fluid) by hypodermic needle via several puncture sites to the edematous prepuce for evacuation of trapped fluid.

Invasive treatment

  • In extreme, or reoccurring, cases it may be necessary for the vet to perform a surgical dorsal slit incision, under anesthesia, to enlarge the preputial orifice.
Pain management:
  • Lidocaine gel applied to the area will enable manipulation without pain.
  • Banamine injection for pain may be given if your veterinarian feels it is warranted.
  • Over the counter children’s Tylenol, Advil, or Motrin may be used for light pain, discomfort, and to help reduce inflammation.
Follow up care:
  • Apply a corticosteroid ointment
  • Oral antimicrobial as directed

For more information regarding the above medications see the: Rat Medication Guide.

Nursing Care

  • If the doctor performs a dorsal slit to the foreskin, keep the area clean and follow wound care as directed by your veterinarian.
  • Give appropriate pain medication such as indicated.
  • Keep the rat on soft towels to prevent irritation or contamination from bedding particles.
  • Use white (or light colored) towels in the environment to monitor urination.
  • Refrain from breeding activity.
  • Maintain a clean habitat.
  • House the rat alone if his cage mates lick off the lubricant/ointment.
  • Give antimicrobials as directed by the veterinarian.
  • Control diet, and monitor weight.

Return to the vet if any of the following occur after initial treatment:

  • Large scrapes on the penis.
  • Areas of tissue that are black, green, or gray.
  • Difficult with/or lack of urination.
  • Temperature is high or low.
  • The condition reoccurs.
  • Bleeding from the penis or sheath is noticed.
  • Hematuria (blood in urine) is seen.
  • A discharge/drainage from penis or sheath.
  • A swelling in the groin area.
  • Other signs of illness develop.


  • Swelling resolved
  • Penis returned to sheath
  • Free of pain
  • Paraphimosis does not reoccur
  • Underlying medical problems treated and resolved
  • Weight reduced if obese


  • There is no known prevention in such small creatures as rats other than to maintain their cleanliness by keeping their habitat clean, treating any urinary tract infections early, provide grooming care of the elderly and paralyzed male rat, and maintaining a healthy weight for the rat.

  1. Cahill, D., & Rane, A. (1999). Reduction of paraphimosis with granulated sugar. BJU Int, 83(3), 362. Retrieved November 30, 2008, from the Medline database.
  2. Choe, J. (2000, December 15). Paraphimosis: Current Treatment Options. Retrieved November 30, 2008, from
  3. Donohoe, J. (n.d.). Paraphimosis. Retrieved November 30, 2008, from
  4. Phimosis. (n.d.). Retrieved November 30, 2008, from


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