SYMPTOM
Urinary incontinence
Owners may notice wet patches where the dog has been lying or sleeping, urine dribbling while the dog stands or walks, or a damp, urine-stained coat around the vulva or prepuce. The dog often seems unaware of the leak. Repeated contact with urine can scald the skin in these areas.
Neurological
Conditions affecting the nerves that control bladder storage and emptying can lead to involuntary urine loss. This may involve spinal cord changes, nerve compression, or disruption of the signals between the brain, spinal cord, and bladder wall. Leakage that starts suddenly alongside weak or wobbly back legs can follow a disc pressing on the spinal cord, which can also stop the bladder emptying properly.
Hormonal
Low levels of sex hormones after neutering, particularly in spayed female dogs, can reduce the tone of the urethral sphincter, the muscle that keeps urine contained. This is called urethral sphincter mechanism incompetence. Affected dogs typically leak urine without noticing while asleep or lying down, but pass urine normally otherwise.
Structural
Anatomical variations or changes in the bladder, urethra, or surrounding tissues can alter how urine is stored and released. This may involve congenital differences, scarring from previous inflammation or surgery, or positional shifts within the pelvis.
Inflammatory or infectious
Irritation or infection of the bladder lining can bring on sudden, frequent urges to pass urine and lower the amount the bladder holds before it empties, sometimes resulting in small-volume leaks.
Age-related
Leakage from reduced sphincter tone may become more noticeable in middle-aged and older dogs, when other conditions can make it more obvious. Reduced mobility or cognitive changes can also alter awareness of bladder fullness or access to usual toileting areas. These patterns can overlap with other age-associated changes in mobility and general health.
Behavioural or environmental
In some cases, apparent incontinence may reflect difficulty accessing usual toileting areas, reluctance to adopt normal postures due to discomfort elsewhere, or learned patterns related to past experiences. Distinguishing involuntary leakage from voluntary but poorly timed urination can matter.
Why timing matters
Early observation
When incontinence first appears, the pattern of leakage can offer clues about the underlying mechanism. Small volumes leaked during rest or sleep, in a dog that otherwise passes urine normally, may point towards reduced sphincter tone. Constant dribbling from a bladder that stays full points instead to a bladder that cannot empty, called overflow incontinence, which can follow a blockage of the urethra or a spinal cord problem. Whether the dog seems surprised by the leakage can also be informative.
Later presentation
If incontinence continues or worsens over weeks to months, it may indicate progression of an underlying process, inadequate compensation by surrounding structures, or the development of secondary changes such as skin irritation or behavioural adjustments. Persistent leakage can also make it harder to distinguish the primary pattern from adaptive changes in drinking, posture, or toileting behaviour.
Some forms of incontinence remain stable for extended periods, particularly when tied to stable hormonal or structural factors. Others may fluctuate with activity level, weight, hydration, or concurrent illness. Individual variation in pelvic anatomy, muscle tone, and compensatory capacity means that two animals with similar underlying patterns can follow quite different trajectories over time.
Conditions commonly associated
Urinary Tract Infection in Dogs
Urinary tract infections can cause inflammation and irritation of the bladder lining, which can trigger sudden urges to pass urine that the dog cannot hold, so small leaks may occur alongside more frequent urination or straining.
Prostate Disease
Prostate disease in male dogs can cause the gland to enlarge or become infected, placing pressure on the urethra or affecting the sphincter mechanism that controls urine release, which may result in dribbling or leakage.
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Transitional Cell Carcinoma
Transitional cell carcinoma tends to develop in the region where the bladder meets the urethra, and tumour growth in this area can interfere with the normal closure of the urinary sphincter or alter bladder wall compliance, leading to involuntary urine loss.
Degenerative Myelopathy in Dogs
Degenerative myelopathy involves progressive loss of nerve function in the spinal cord, and when the affected segments include those controlling bladder sphincter tone, incontinence can develop as the signals governing voluntary urine retention are weakened or lost.
Cauda Equina Syndrome
Nerve compression at the base of the spine can disrupt bladder control, although in dogs with degenerative lumbosacral stenosis incontinence is more often a separate problem than a direct result of the compression.
Cannabis Toxicity
Dribbling urine is a recognised sign of cannabis toxicity in dogs, usually seen alongside commoner signs such as wobbliness, sensitivity to touch and lethargy.
Ectopic Ureters
When a ureter bypasses the bladder and opens beyond the sphincter, urine dribbles out continuously rather than being stored and passed normally.
Intervertebral Disc Disease in Dogs
A disc pressing on the spinal cord can cause sudden back-leg weakness, and a dog that loses the use of its back legs usually also loses the ability to empty its bladder, leading to dribbling from an overfull bladder.
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When to explore further
If there is straining with little or no urine passing, constant dribbling alongside a swollen, firm or painful belly, or leakage that starts with sudden weakness or wobbliness of the back legs. These signs can mean the bladder cannot empty or the spinal cord is affected, and how full the bladder is cannot be judged at home. A complete blockage of the urethra leads to a build-up of waste products in the blood within 36 to 48 hours and can be fatal within about 72 hours.
If incontinence appears alongside other changes such as increased thirst, altered appetite, shifts in gait or posture, or difficulty rising or settling.
If the volume, frequency, or timing of leakage changes noticeably over days to weeks, or if the animal begins to show awareness or distress around the leakage.
If there is visible blood in the urine or signs of discomfort when passing urine.
If the incontinence starts following recent surgery, injury, or a period of illness, or if it coincides with the introduction of new medications or dietary changes.
If leakage occurs frequently enough to affect the animal's comfort, create hygiene challenges, or require significant changes to household routines.
Urinary incontinence gains meaning in the context of the animal's age, reproductive history, body condition, and any other observations over the same timeframe. Keeping a loose record of when leakage occurs, the volumes involved, and any accompanying behaviours can help clarify the pattern. This picture, alongside the animal's broader history and physical findings, shapes the conversation about what might be contributing and what options may be worth exploring.
Last reviewed: 9 October 2026 · Dr Alastair Greenway MRCVS