Prostate Gland Enlargement (Benign Prostatic Hyperplasia) in Dogs

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Key takeaways

In male dogs, the prostate is a small gland found near the neck of the urinary bladder, through which the urethra passes and functions to create some of the fluids found in semen. The most common ailment affecting the canine prostate is benign prostatic hyperplasia (BPH), which is an enlargement of the prostate. 

  • BPH is caused by the influence of male sex hormones over time
  • All intact male dogs eventually develop BPH if they live out their full life expectancy
  • BPH is often asymptomatic, but typical symptoms include urinary incontinence, straining to urinate and/or defecate, and bloody urine or semen
  • Diagnosis is made by palpation of an enlarged prostate, diagnostic imaging and biopsy of the prostatic tissue may be indicated
  • Treatment is castration (neutering)
  • If the dog’s fertility must be preserved, medications are available
  • Prognosis is good
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A closer look: Prostate Gland Enlargement (Benign Prostatic Hyperplasia) in Dogs

The prostate is a small gland in the male reproductive system which makes components of semen and acts to switch urethral function between urination and ejaculation. In intact males, the presence of sex hormones over time leads to an enlargement of the prostate, or benign prostatic hyperplasia (BPH) which can cause other symptoms and discomfort.

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Risk factors

BPH is very common in intact male dogs (neutered males are not affected). By 4 years of age, approximately half of intact male dogs have signs of BPH, and more than 90% have signs by 8 years of age. Symptoms mimic those of other, more serious conditions, making early detection critical.

Untreated BPH predisposes dogs to prostatic infections. Overall the prognosis is good with treatment.

Possible causes

The cause of BPH is the effect of male sex hormones from the testes on the prostate gland over time.

Main symptoms

BPH is usually asymptomatic.

Testing and diagnosis

The first step of diagnosis of possible BPH is a complete physical exam, including a rectal exam. Urinalysis, urine culture, general blood work to rule out other diseases, and diagnostic imaging may also be required. Biopsy may be performed to rule out infection and cancer, and the prostatic fluid may be analyzed. Canine Prostate-Specific Arginine Esterase (CPSE) measurement may be helpful as a screening tool for BPH. It may take several different tests to pinpoint the precise source of enlargement as there are numerous prostate ailments. Definitive diagnosis is only possible by biopsy.

Steps to Recovery

Treatment is not necessary in asymptomatic dogs, but castration is the gold standard. This is curative; the prostate gland shrinks back to normal size within months. For dogs that must be left intact for breeding or showing, there are several medications that have been used effectively to treat BPH. As soon as the medication is stopped, however, the prostate starts to enlarge again. Advanced techniques such as pulsed electromagnetic field therapy and magnetic resonance-guided ultrasonic ablation may be available in specialty practices. Supportive care includes enemas and stool softeners for tenesmus (straining to defecate).

Benign prostatic hyperplasia is progressive, and never resolves on its own. If untreated, it can lead to infertility and infection. Within 3 weeks after castration, the prostate starts to shrink, and within 3-4 months will have returned to normal size. Prognosis is good overall.


Castration is the only prevention for benign prostatic hyperplasia. BPH is not contagious.

Is Prostate Gland Enlargement (Benign Prostatic Hyperplasia) in Dogs common?

BPH is the most common disorder of the prostate gland, and is extremely common in intact male dogs.

Typical Treatment

  • Benign neglect
  • Castration (neuter)
  • Medications
  • Supportive care


Michelle Kutzler, DVM, PhD, DACT - Writing for Merck Veterinary Manual
Michelle Kutzler, DVM, PhD, DACT - Writing for Merck Veterinary Manual
Bruce W. Christensen, DVM, MS - Writing for Veterinary Clinics of North America: Small Animal Practice
Malcolm Weir, DVM, MSc, MPH; Ryan Llera, BSc, DVM; Ernest Ward, DVM - Writing for VCA Animal Hospitals
Dr. Laci Schaible - Writing for Hill's Pet Nutrition
Bruce W Christensen - Writing for Veterinary Clinics of North America: Small Animal Practice
S. Romagnoli - Writing for Veterinary Information Network®

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