CONDITION

Prostate Disease

Why this matters now

Prostate conditions occur almost exclusively in intact (unneutered) male dogs, with prevalence increasing significantly with age. Benign prostatic hyperplasia affects the majority of intact male dogs over five years of age. Other prostate conditions such as prostatitis or prostatic cysts may develop at various ages, whilst prostatic neoplasia is more commonly seen in older dogs, including those that have been neutered.

Prostate enlargement typically develops gradually, often remaining unnoticed until it begins affecting surrounding structures. As the gland enlarges, it may compress the urethra or rectum, leading to urinary or defecation difficulties. Bacterial prostatitis can develop acutely with sudden illness, or may become chronic with more subtle persistent signs. Early changes may be incidental findings, whilst advanced disease can significantly impact quality of life.

Signals & patterns

Early signals

Mild straining to defecate

Enlargement of the prostate can compress the rectum, making passage of faeces more difficult.

Ribbon-like or flattened stools

Rectal compression may alter faecal shape as it passes the enlarged gland.

Blood-tinged discharge from the prepuce

Prostatic fluid containing blood may be seen independent of urination.

Intermittent difficulty initiating urination

Urethral compression may cause occasional hesitancy or interrupted urine flow.

Later signals

Obvious straining with urination or defecation

More significant prostatic enlargement causes marked difficulty with elimination.

Stiff or stilted hind leg gait

Prostatic pain or enlargement may cause discomfort affecting hindquarter movement.

Signs of systemic illness

Bacterial prostatitis may cause fever, lethargy, and general unwellness.

Blood in urine

Prostatic bleeding may become apparent in urine, particularly at the end of urination.

Click to read about the biological mechanisms

How this is usually investigated

Evaluation typically combines physical examination with imaging and laboratory tests to characterise the nature and extent of prostatic changes.

Rectal palpation

Purpose: To assess prostate size, symmetry, texture, and pain response
Considerations: Provides initial information about gland characteristics. Asymmetry or irregular texture may warrant further investigation.

Abdominal ultrasound

Purpose: To visualise the prostate architecture and identify cysts, abscesses, or masses
Considerations: Allows detailed assessment of internal structure and can guide sampling procedures if needed.

Urinalysis and culture

Purpose: To check for urinary tract infection and assess urine characteristics
Considerations: Important when prostatitis is suspected. Prostatic wash or ejaculate culture may be more specific.

Blood tests

Purpose: To evaluate overall health and check for signs of infection or systemic effects
Considerations: May reveal elevated white blood cell counts with infection or other abnormalities requiring attention.

Prostatic wash or fine needle aspirate

Purpose: To obtain samples directly from the prostate for cytology and culture
Considerations: Can help differentiate between benign enlargement, infection, and neoplasia. Requires ultrasound guidance or catheter technique.

Options & trade-offs

Management depends on the specific prostatic condition and whether the dog is to be used for breeding. Various approaches may be appropriate for different situations.

Neutering (castration)

Removal of testosterone source typically leads to significant prostatic regression within weeks.

Trade-offs: Highly effective for benign prostatic hyperplasia and removes future risk. Not appropriate for breeding dogs. Does not address prostatic neoplasia.

Medical management

Medications that reduce testosterone effects or prostatic size may be used in breeding dogs or when surgery is not desired.

Trade-offs: Can provide temporary reduction in prostate size. Effects reverse when medication stops. Various drug options exist with different profiles.

Antimicrobial therapy

Antibiotics selected based on culture and sensitivity testing for bacterial prostatitis.

Trade-offs: Prolonged treatment courses are often needed as antibiotics penetrate prostatic tissue variably. Relapse can occur with chronic infection.

Surgical drainage or marsupialisation

Procedures to drain prostatic cysts or abscesses that do not resolve with medical management.

Trade-offs: May be needed for large cysts causing ongoing problems. Combined with neutering for best outcomes.

Supportive care for defecation

Stool softeners or dietary modification to ease defecation whilst other treatments take effect.

Trade-offs: Can provide symptomatic relief. Addresses consequences rather than underlying cause.

Common misconceptions

Misconception:

"Neutering increases prostate cancer risk"

Reality:

Whilst some studies suggest neutered dogs may have proportionally more prostatic neoplasia, this is likely because benign enlargement is eliminated. Prostate cancer is uncommon overall in dogs.

Misconception:

"Straining to defecate always indicates constipation"

Reality:

In intact male dogs, prostatic enlargement commonly causes defecation difficulty by compressing the rectum, which may be misattributed to primary bowel problems.

Misconception:

"Blood in urine always indicates bladder problems"

Reality:

In intact male dogs, prostatic disease is a common source of haematuria, and the prostate should be evaluated alongside the bladder.

For owners of intact male dogs, awareness that prostate changes are common with age can prompt attention to subtle signs such as altered defecation patterns or hindquarter discomfort. Noting whether urination has changed in character, or if any discharge is observed, provides useful information for veterinary discussions. The dog's breeding status influences which management approaches may be considered.

Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS