SYMPTOM
Blood in urine
Urine that appears pink, red, or brown in colour, or the presence of blood spots or drops at the end of urination.
Urinary tract infection
Bacterial cystitis is one of the most common causes of haematuria in dogs. The inflammatory response to bacterial colonisation of the bladder mucosa increases vascular permeability and can erode the urothelial lining, allowing red blood cells to enter the urine. Blood is often most noticeable at the end of urination and may be accompanied by increased frequency, straining, and discomfort. Female dogs are more commonly affected due to their shorter urethra.
Urinary stones (urolithiasis)
Stones within the bladder or urethra can cause mechanical irritation and trauma to the urinary tract lining as they move or as the bladder wall contracts around them during urination. Struvite and calcium oxalate stones are the most common types in dogs. The haematuria may be intermittent, sometimes more pronounced after physical activity. Urethral stones can cause obstruction and more dramatic bleeding.
Bladder or urinary tract neoplasia
Tumours of the bladder wall — most commonly transitional cell carcinoma — can produce persistent or intermittent haematuria as the tumour erodes through the mucosal surface. This is more commonly seen in older dogs, with certain breeds (Scottish Terriers, Shetland Sheepdogs, West Highland White Terriers) being overrepresented. The bleeding may be accompanied by other lower urinary tract signs that can mimic chronic UTI.
Coagulopathy or platelet disorder
Disorders affecting the blood's ability to clot normally can produce haematuria as part of a broader bleeding tendency. Thrombocytopenia, inherited or acquired clotting factor deficiencies, and exposure to anticoagulant rodenticides can all cause bleeding into the urinary tract. In these cases, other signs of abnormal bleeding — such as petechiae, ecchymoses, or prolonged bleeding from wounds — may also be present.
Prostatic disease
In intact or neutered male dogs, prostatic conditions including benign hyperplasia, prostatitis, prostatic cysts, and prostatic neoplasia can produce haematuria or blood dripping from the prepuce independent of urination. Prostatic blood typically enters the urine via the prostatic urethra and may be present throughout the urine stream rather than concentrated at the beginning or end.
Trauma or vigorous exercise
Physical trauma to the urinary tract or kidneys, or strenuous exercise, can produce transient haematuria. Exercise-induced haematuria is typically mild and self-limiting, resolving within hours to a day of rest. Traumatic haematuria from blunt abdominal injury may be more significant and can indicate damage to the kidneys, bladder, or urethra.
Why timing matters
Early observation
When blood in the urine is first noticed, it typically represents an active process affecting the urinary tract lining or kidney. The colour and timing of blood relative to the urine stream can provide initial characterisation: blood throughout the stream may suggest bladder or upper tract origin, blood at the end of urination often suggests a bladder or urethral source, and blood at the beginning may suggest a urethral or prostatic source. Early haematuria from UTI is often accompanied by other lower urinary tract signs and typically responds to appropriate treatment. Isolated, painless haematuria without other urinary signs warrants particular attention as it may suggest a neoplastic or structural cause.
Later presentation
Persistent or recurrent haematuria over weeks suggests an ongoing process that has not resolved spontaneously. If initial treatment for suspected UTI has not resolved the bleeding, other causes become more important to consider. Chronic haematuria can lead to iron deficiency over time if significant blood loss is occurring, though this is uncommon with most causes of urinary tract bleeding. Progressive worsening of haematuria — from occasional pink-tinged urine to consistently red or passing clots — indicates an advancing process.
The trajectory depends on the underlying cause. UTI-related haematuria typically resolves within days of appropriate antibiotic therapy. Stone-related bleeding may fluctuate with the stone's position and movement within the urinary tract. Neoplastic causes tend to produce progressive or persistent haematuria that worsens over time. Exercise-induced haematuria is self-limiting and resolves with rest. Monitoring the pattern of bleeding, its relationship to treatment, and whether associated signs are developing or resolving provides important context about the underlying process.
Conditions commonly associated
Urinary Tract Infection in Dogs
Urinary tract infection is one of the most common causes of blood in the urine in dogs. The inflammatory response to bacterial colonisation of the bladder mucosa increases vascular permeability and can erode the urothelial lining, allowing red blood cells to enter the urine.
Urinary Stones (Urolithiasis)
Urinary stones irritate the bladder lining through mechanical abrasion, causing microhaemorrhage that produces visibly blood-tinged urine, often intermittently.
Prostate Disease
Prostatic disease frequently causes haematuria, with blood often most noticeable at the end of urination.
Transitional Cell Carcinoma
Transitional cell carcinoma causes bleeding from the tumour surface into the urine, often the first sign noticed by owners.
When to explore further
When blood in the urine persists beyond a few days or recurs after apparent resolution, the pattern suggests an ongoing process rather than a transient event and may warrant investigation to identify the source.
When haematuria is accompanied by straining, increased frequency, or apparent discomfort during urination, these lower urinary tract signs help localise the source and suggest an active inflammatory or irritative process in the bladder or urethra.
When blood is present in the urine without any other urinary signs — painless haematuria — this pattern is noteworthy because it may suggest processes such as neoplasia or coagulopathy rather than inflammatory conditions that typically produce concurrent discomfort.
When haematuria occurs alongside signs of bleeding elsewhere — such as bruising, nosebleeds, or prolonged bleeding from minor wounds — the combination suggests a systemic clotting problem rather than a localised urinary tract issue.
When blood in the urine develops in an older dog, particularly breeds known to be predisposed to transitional cell carcinoma, the age and breed context adds importance to thorough investigation even if initial signs are mild.
Noting the characteristics of the haematuria — whether blood appears at the beginning, middle, or end of urination, its colour (pink, red, or brown), whether clots are present, and whether it occurs with every urination or intermittently — can help characterise the source. Observing whether the dog shows other urinary signs such as increased frequency, straining, or discomfort provides additional context. Collecting a urine sample for analysis can be informative and is often the first step in understanding the cause of urinary bleeding.
Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS