Paraphimosis in dogs: a penis stuck outside the sheath

Overview

The prepuce is the skin fold and enclosed space that normally protect the penis. Its shape, length and opening help keep the penis covered. Retractor muscles hold the penis inside the sheath.

Acute paraphimosis often occurs after an erection. In a chronic problem, the penis may also slip out because of inadequate support, without a constricting ring. Urgency therefore depends particularly on whether the tissue is trapped and compressed.

Paraphimosis and priapism are different conditions. Priapism is an erection that continues without sexual stimulation. However, it can also leave the penis partly outside the sheath.

The urethra runs along the full length of the penis. Its opening is at the tip.

Causes

Skin at the sheath opening can turn inwards and trap the exposed penis. Constriction impairs drainage through the veins. It also makes normal subsidence of the erection difficult. Fluid accumulating in the tissue rapidly increases swelling.

A sheath opening that is too small can prevent the penis returning. A foreign object around the penis can cause the same problem. Hair at the opening can form a constricting ring. Penile injury is another possible cause.

A congenitally inadequate sheath may leave part of the penis constantly unprotected. Partial loss of the sheath in an accident can also reduce coverage. A problem with the nerve supply to the retractor muscles may impair return. Rarely, a penile tumour prevents it.

Risk factors

Paraphimosis occurs particularly after manual semen collection. It also occurs with mating, but less often than after collection. High sexual activity in young entire males may predispose to it.

In young, small, long-haired dogs, hair entanglement may combine with a narrow or short sheath. In Chihuahuas, a pendulous sheath and weak retractor muscle may underlie the penis slipping out. In large dogs, neurological disease of the lumbosacral region may also be associated with incomplete return.

A drug-associated persistent erection can also leave the penis partly outside the sheath.

Typical symptoms

The typical change is directly visible around the penis and sheath:

• The penis remains visible and does not return fully inside its protective sheath.

• The exposed part swells noticeably and rapidly when blood drainage is blocked.

• The lining dries from continued exposure.

• Your dog starts licking or biting the exposed penile tissue.

• In a severe case, the glans changes colour as blood supply is impaired.

Sensation in the glans may decrease with advanced damage. Difficulty urinating and blood in the urine may accompany tissue injury. Appetite may also decrease with severe penile damage.

Early on, penile tissue may look normal and not yet be painful.

A dog may still eat and drink despite dead tissue in the penis. Normal walking may also continue despite severe local damage.

Complications and consequences

Ongoing disruption of blood supply can cause irreversible penile tissue death. Licking and biting can extend the local damage. Injury involving the urethra may make urination difficult. The severity and duration of damage affect the outlook.

Extensive irreversible damage may require partial or complete penile removal. A new urinary opening can be created in the scrotal region at the same time. Later problems with this opening include narrowing and recurrent urinary tract infections.

In one 2-year-old dog, penile exposure lasting 3 weeks was already associated with tissue death.

Creating a urinary opening also carries risks of bleeding, wound infection and wound breakdown.

Diagnosis at the vet

Examining the sheath and penis

Diagnosis begins with clinical examination of the penis and sheath. The assessment establishes previous similar episodes and treatments. Examination distinguishes conditions such as a congenitally short sheath with associated penile exposure. A tumour or haematoma is also considered.

The vet assesses glans colour and sensation to evaluate blood supply. Severe pain may require sedation for handling. Opening the sheath may be necessary to examine its interior thoroughly.

Investigating a prolonged or unusual problem

A condition unresponsive to usual treatment is also investigated for priapism. Penile ultrasound helps distinguish this. Possible causes of priapism include neurological disorders, medicines and blood vessel abnormalities. Sometimes the cause remains unknown.

Neurological examination forms part of surgical assessment when investigating impaired penile return. Findings may prompt spinal X-rays. Abnormal tissue can be investigated with cell or tissue samples.

Priapism is divided into ischaemic disease, with impaired blood flow, and a non-ischaemic form. A persistent erection is an emergency if blood flow is blocked. Examination also distinguishes phimosis, in which the penis cannot be exposed from within the sheath. Phimosis may become apparent only when mating attempts fail.

Treatment

Restoring blood flow

The vet gently cleans the exposed penis and applies lubrication. The aim is to return it inside the protective sheath. Swelling starts to decrease rapidly once blood flow is restored. A cool compress may help reduce swelling.

More advanced cases may require sedation or general anaesthesia. Constricting material is removed through an incision in the sheath when needed. A temporary tightening suture may help keep the replaced penis inside. Urethral injury may require a temporary urinary catheter connected to a closed collection system.

The catheter aims to prevent later narrowing of the damaged urethra.

Correcting a structural problem

Recurrent or persistent paraphimosis may need surgery to correct the sheath opening. A short sheath can provide more coverage if advanced forwards. Phallopexy, surgery fixing the penis in place, is another option. The method depends on cause, duration and tissue viability.

The corrective surgical wound may break down during healing. Penile fixation may also fail before strong scar tissue forms. A changed urine stream after surgery may wet the front legs or underside of the chest.

Treating severe tissue damage and recovery

Extensive tissue death and irreversible damage may make penile removal and a urinary opening necessary. The urethra is opened onto the skin so urine can leave by a new route. In the scrotal region, it lies near the surface and has a relatively large diameter.

In one dog operated on for severe paraphimosis, the urinary opening bled slightly for the first 3 days. In another dog, similar bleeding lasted 7 days and decreased daily. The latter dog was well and urinating without difficulty at a 4-month review.

In the same dog, a protective collar prevented licking and biting of the surgical site for 2 weeks. Postoperative pain relief is planned individually. Antimicrobial selection considers factors including suspected infection and any culture and susceptibility results.

A urinary opening can shrink by up to 50% during healing, which is considered when creating it.

Opening the urethra at scrotal level causes less bleeding than an opening made higher up.

Surgical outcomes for recurrent paraphimosis

After combined preputial advancement and phallopexy, 14 of 16 dogs, or 87.5%, improved. These dogs had paraphimosis unresponsive to non-surgical treatment. The underlying cause was unknown. Outcomes were assessed through an owner questionnaire.

Paraphimosis did not recur in 8 dogs, or 50%. Occasional recurrence occurred in 3 dogs, or 18.75%, without needing further treatment. Another 3, or 18.75%, had recurrence requiring intermittent medication, but were better than before. Two dogs, or 12.5%, had no significant improvement.

Major complications occurred in 2 of 16 dogs, or 12.5%. Minor complications occurred in one, or 6.25%. Improvement and complete resolution were therefore different outcomes.

Median duration of these combined operations was 60 minutes, with a range of 45–75 minutes. No complications occurred during the operations themselves.

Prevention

Trimming long hair around the sheath opening helps prevent problems from hair entanglement. Lubrication under veterinary guidance may help protect tissue when needed. Close supervision of entire males near bitches in season reduces risks associated with sexual activity.

Early treatment of a trapped, exposed penis prevents irreversible tissue damage. A structural coverage problem may require surgical correction. Castration does not help treat priapism because this erectile disorder does not depend on testosterone.

Important for dog owners

Record when the penis remained exposed and whether this followed mating, semen collection or another event. Explain whether it is the first episode or a recurring problem and which treatments have been tried. Mention current medicines, previous injuries and any back or hindleg symptoms. Monitor whether urine passes normally and where the stream goes.

Ask whether the problem is constriction, inadequate coverage or a persistent erection. After treatment, agree how to protect the area, what to monitor and when review will take place. If a urinary opening has been created, ask for written instructions on monitoring bleeding, the wound and urination. Discuss which signs require an immediate return to emergency care too.

Bleeding from the surgical site should decrease each day.

Frequently asked questions

Can paraphimosis resolve by itself?

A penis that does not return promptly on its own needs veterinary care. Exposed lining may swell, dry and become painful. Early replacement is easier than after severe swelling develops. A recurrent problem may require surgical correction of the sheath.

Is paraphimosis the same as a tight sheath?

In paraphimosis, the penis cannot return fully inside the sheath. In phimosis, it cannot be exposed from inside. A narrow sheath opening may be involved in either problem. Phimosis may result from congenital structure or previous injury, for example.

Does castration always help?

Castration does not correct priapism, a persistent erection without sexual stimulation. Paraphimosis may also result from a sheath opening that is too small. Sometimes congenital structure or injury leaves inadequate coverage. Treatment then targets the underlying structural problem.

Is surgery always needed?

Early paraphimosis may be treated with gentle cleaning, lubrication and replacement inside the sheath. More advanced cases may need additional treatment or surgery. Extensive tissue death may require partial or complete penile removal.

Can a dog urinate after penile removal?

A new urinary outlet can be created in the scrotal region during penile removal. One dog treated this way was still urinating without difficulty at a 4-month review. However, possible later problems include narrowing of the opening and recurrent urinary tract infections.