Prostatitis is a bacterial infection of the prostate gland in dogs, and it ranges from a sudden, severe illness to a low-grade infection that lingers for months without obvious symptoms. It accounts for roughly 40% of all prostatic disease cases in dogs and occurs almost exclusively in intact (unneutered) males, though neutered dogs can occasionally develop it too.
Acute vs. Chronic Prostatitis
The two forms of prostatitis look and feel very different from your dog’s perspective. Acute prostatitis hits suddenly. It’s driven by a severe bacterial infection that causes rapid inflammation of the prostate, and it can progress to abscess formation if left untreated. Dogs with acute prostatitis are visibly sick: lethargic, feverish, and often in significant abdominal pain. In severe cases, dehydration, bloodstream infection, and even shock can develop.
Chronic prostatitis is more common and far sneakier. A dog with a chronic prostate infection may show no obvious signs at all. The only clue might be recurrent urinary tract infections that keep coming back despite treatment. Some dogs develop symptoms that overlap with benign prostatic hyperplasia (BPH), a noncancerous enlargement of the prostate, which can make the chronic form harder to identify on its own.
How Dogs Get Prostate Infections
Bacteria reach the prostate through two main routes, and the route often determines which form of prostatitis develops. In acute cases, bacteria typically spread through the bloodstream from an infection somewhere else in the body. In chronic cases, bacteria usually migrate upward from the urethra into the prostate.
The most common culprit is E. coli, the same bacterium behind many urinary tract infections. An underlying condition called benign prostatic hyperplasia plays an important role here. BPH causes structural changes in the prostate tissue that make it more vulnerable to bacterial colonization. Since BPH affects the vast majority of intact male dogs by middle age, it essentially sets the stage for prostatitis to develop.
Symptoms to Watch For
The signs of acute prostatitis tend to be obvious but nonspecific, meaning they could point to many different illnesses. You might notice:
- Severe abdominal pain, especially in the lower belly or hindquarters
- Fever and lethargy, with your dog refusing food or reluctant to move
- Stiff or unusual gait, because the swollen prostate presses on nearby structures
- Straining to urinate or defecate, sometimes with blood in the urine
- Discharge from the penis, which may be bloody or cloudy
Chronic prostatitis is a different story. Your dog may seem perfectly normal between bouts of urinary tract infections. Some dogs develop intermittent discomfort, mild straining, or occasional bloody urine, but these signs come and go and are easy to dismiss. If your intact male dog keeps getting UTIs, a prostate infection is one of the first things your vet will consider.
How Prostatitis Is Diagnosed
Vets typically start with a rectal exam, feeling the prostate through the rectal wall to check its size, shape, and whether it causes pain. In acute cases, the prostate is often swollen and extremely tender. In chronic cases, the gland may feel irregular or asymmetrical but isn’t necessarily painful.
Ultrasound gives a clearer picture of what’s happening inside the gland, revealing inflammation, fluid pockets, or abscesses. Urine culture identifies the specific bacteria involved, which guides antibiotic selection. In some cases, your vet may collect fluid directly from the prostate for culture, though this is avoided in acute cases because of the pain and the risk of spreading bacteria.
Why Untreated Prostatitis Is Dangerous
Left untreated, acute prostatitis can progress to a prostatic abscess, a walled-off pocket of infection inside the gland. This is where the condition becomes life-threatening. The abscess can rupture, spilling infectious material into the abdominal cavity and causing peritonitis. From there, the complications cascade quickly: bloodstream infection, a dangerous clotting disorder, and organ failure. The mortality rate for ruptured prostatic abscesses is high, which is why aggressive early treatment matters so much.
Chronic prostatitis carries lower immediate risk, but the repeated cycles of urinary infection can damage the kidneys over time and significantly reduce your dog’s quality of life.
Treatment and Recovery
Antibiotics are the foundation of treatment, but treating a prostate infection is harder than treating a standard UTI. The prostate has a barrier that blocks many common antibiotics from reaching effective concentrations inside the gland. Drugs that are fat-soluble and carry a positive charge penetrate this barrier best. Fluoroquinolones are typically the first choice for E. coli infections, with other options selected based on culture results if the bacteria are resistant.
The course of antibiotics is long, often lasting up to two months. This extended timeline is necessary because the prostate barrier makes it difficult to maintain high enough drug levels to fully clear the infection. Shorter courses frequently lead to relapse, with bacteria surviving deep in the prostate tissue and flaring up weeks later.
For dogs with acute prostatitis who are dehydrated, feverish, or in shock, initial treatment involves hospitalization with intravenous fluids and injectable antibiotics until the dog stabilizes. Once the dog is eating, drinking, and comfortable, treatment transitions to oral antibiotics at home.
The Role of Neutering
Neutering is a central part of the treatment plan for prostatitis in intact dogs. Once antibiotics have been started and the dog is clinically stable, castration is recommended to help resolve the infection and prevent recurrence. Removing the source of testosterone causes the prostate to shrink significantly over several weeks, which reduces the tissue environment that harbors bacteria. Without neutering, prostatitis tends to recur even after a full course of antibiotics, because the enlarged, hormone-stimulated prostate remains a hospitable environment for bacterial growth.
For dogs with prostatic abscesses, neutering is equally important. Combined with appropriate antibiotic therapy and, in some cases, surgical drainage of the abscess, castration gives the dog the best chance of full recovery and prevents the cycle from starting again.
Monitoring During Recovery
During the weeks-long antibiotic course, keep an eye on your dog’s urination habits, energy level, and appetite. A dog that improves initially but then starts straining to urinate, becomes lethargic again, or develops a fever may be relapsing. Recurrent UTIs after completing treatment are a red flag that the prostate infection wasn’t fully cleared.
Your vet will likely want to recheck a urine culture after the antibiotic course ends to confirm the infection is gone. For chronic cases, periodic rechecks over the following months help catch any recurrence early, before it becomes a bigger problem.