CONDITION
Prostatic Hyperplasia
Prostatic hyperplasia refers to enlargement of the prostate gland, which sits just behind the bladder in intact male dogs. This enlargement happens as a normal consequence of hormonal influence over time, and tends to develop gradually in most uncastrated males as they age. The prostate tissue responds to testosterone and related hormones by increasing in size, though the gland remains structurally normal. Owners often notice changes in toileting—straining to pass faeces, ribbon-shaped stools, or occasionally blood in the urine or dripping from the prepuce when no urination is happening. Some dogs show no outward signs at all, and the enlargement is identified during examination for another reason. The size of the prostate does not always correspond to the severity of signs; a moderately enlarged gland may cause significant difficulty, while a larger one may cause none. This page explores what an owner may observe, the hormonal and structural changes occurring in the gland, how prostatic hyperplasia is investigated and distinguished from other prostatic conditions, and the range of approaches available for managing it. These approaches vary in how quickly they work, their permanence, and their suitability depending on whether the dog is used for breeding.
Why this matters now
Prostatic hyperplasia tends to develop in intact male dogs from middle age onwards, typically becoming detectable from around five to six years of age. The condition is driven by cumulative hormonal exposure, so prevalence increases with age—by eight to ten years, most uncastrated males will have some degree of prostatic enlargement, though not all will show clinical signs. There is no strong breed predisposition; the process reflects normal ageing physiology in the presence of testicular hormones rather than a specific genetic susceptibility.
Enlargement of the prostate typically progresses gradually over months to years, with the gland increasing in size in response to ongoing hormonal influence. The rate of progression varies considerably between individuals, and some dogs may develop noticeable signs relatively early whilst others remain asymptomatic despite substantial enlargement. The condition does not resolve spontaneously whilst the dog remains intact, and signs may fluctuate in severity depending on the degree of compression exerted on adjacent structures as the gland continues to grow.
Signals & patterns
Early signals
Ribbon-shaped or flattened stools
The enlarged prostate can press against the rectum as it passes through the pelvic canal, narrowing the space available and causing faeces to emerge in a flattened or ribbon-like form. This change in stool shape may be subtle at first and can occur without any straining or discomfort.
Mild straining during defaecation
Pressure from the prostate on the rectum may cause the dog to adopt a prolonged posture or strain gently when passing faeces, even when the stool itself is soft. This is distinct from the straining seen with constipation, as the difficulty relates to mechanical compression rather than stool consistency.
Occasional blood drips from the prepuce
Fresh blood may appear at the tip of the prepuce between urinations, often noticed as small spots on the floor or bedding. This bleeding typically originates from small, fragile blood vessels within the enlarged prostate and can occur intermittently without any other overt signs.
Blood-tinged urine
Urine may appear pink, red, or contain visible streaks of blood, reflecting haemorrhage from the prostate into the urethra. The blood is often most noticeable at the start or end of urination, and the amount can vary from faint discolouration to more obvious contamination.
Later signals
Persistent straining with little or no stool passed
As the prostate enlarges further, compression of the rectum can become more pronounced, leading to repeated, effortful attempts to defaecate with minimal output. This pattern can be distressing and may be mistaken for severe constipation, though the underlying issue is mechanical obstruction rather than hard faeces.
Difficulty or discomfort when urinating
In some cases, significant prostatic enlargement can affect the urethra, leading to a weaker urine stream, prolonged posturing, or apparent discomfort during urination. These signs are less common than defaecatory changes but may emerge if the gland encroaches on the urethral passage.
Recurrent urinary tract infections
An enlarged prostate can alter normal urine flow and drainage, creating conditions that favour bacterial colonisation. Owners may notice increased frequency of urination, discomfort, or persistent blood in the urine, and infections may recur despite treatment if the underlying prostatic enlargement is not addressed.
Click to read about the biological mechanisms
How this is usually investigated
Options & trade-offs
Last reviewed: Invalid Date ·