Fungal Urinary Tract Infection in Dogs (Fungal Infection of the Lower Urinary Tract, UTI)

  • Occurrence: common
  • Location of disease: Abdomen/pelvis
Author: Dr. med. vet. Gisa Löwe | Last modified: 10.08.2026
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When to visit the vet?

Non-urgent see a veterinarian within 2–3 days

?

If the condition worsens / symptoms persist, consult a veterinarian.

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Definition

Fungal infection of the urinary tract in dogs is an infection of the lower urinary tract caused by various types of fungi. This condition can lead to inflammatory conditions and further health complications if not detected and treated in time.

The most important facts at a glance

Fungal infections of the urinary tract in dogs are fungal infections caused by fungi such as Candida entering the urinary tract. These fungi are normally harmless inhabitants of the skin and mucous membranes but can become pathogenic if the immune system is weakened. Infections commonly occur in the bladder and urethra. A weakened immune system, which can be caused by diseases such as diabetes or long-term antibiotic therapy, can increase the risk of infection. Common symptoms include urinary urgency, pain during urination, and blood in the urine. Diagnosis is made through clinical examinations and laboratory analyses of the urine to detect fungi. A urine culture helps identify the fungal species and determine its sensitivity to antifungals. Treatment includes the administration of antifungals such as fluconazole as well as the treatment of underlying diseases. The prognosis is good with early treatment, but severe infections can cause permanent damage. Prevention includes strengthening the immune system through a balanced diet, limited use of antibiotics, and regular veterinary examinations. Good hygiene and adequate fluid intake are also important to reduce the risk of infection.

Causes

Mycoses are fungal infections caused by fungi entering the body. In dogs, various types of fungi can infect the urinary tract, with Candida species being the most common pathogens. These fungi are normally harmless inhabitants of the skin and mucous membranes but can become pathogenic if the immune system is weakened or if there are changes in the body’s environment.

The urinary tract consists of several components, including the kidneys, ureters, bladder, and urethra. A fungal infection can occur in any of these areas, but it is most common in the lower urinary tract – i.e., the bladder and urethra. Fungi can enter the urinary tract through the bloodstream or directly through the urethra.

Causes of a fungal infection of the urinary tract include a weakened immune system, for example, due to diseases like diabetes or long-term antibiotic use, which disrupts the natural balance of microorganisms. Anatomical abnormalities or injuries to the urinary tract can also increase the risk of infection.

Symptoms

Rare symptoms:

Dogs with a fungal infection of the urinary tract can show a variety of symptoms that often resemble those of a bacterial urinary tract infection. The most common symptoms include increased urinary urgency, pain during urination, and blood in the urine. Affected dogs may also show signs of general malaise, such as fever, loss of appetite, and lethargy.

In some cases, excessive grooming of the genital area may occur as the dog attempts to relieve itching or discomfort. In more severe infections, kidney function may be impaired, which can manifest as increased thirst and increased urination.

Therapy

The therapy for a fungal infection of the urinary tract in dogs typically requires the use of antifungals that are specifically effective against the identified fungal species. The choice of the appropriate medication depends on the type of fungus and its sensitivity, which is determined by urine culture.

Commonly used antifungals include fluconazole and itraconazole, which are administered orally. Treatment can take several weeks to months, depending on the severity of the infection and the dog’s response to therapy.

In addition to medication therapy, it is important to address underlying factors that may have contributed to the infection, such as the management of diabetes or the discontinuation of excessive antibiotic therapy. Regular follow-up examinations and urine analyses are crucial to monitor treatment success and prevent relapses.

Prognosis and follow-up care

The prognosis for dogs with a fungal infection of the urinary tract depends on several factors, including the speed of diagnosis, the severity of the infection, and the response to therapy. With early detection and appropriate therapy, the prognosis is generally good, and most dogs recover completely.

However, severe or prolonged infections, especially those affecting the kidneys, can lead to permanent damage. In such cases, the prognosis is more cautious, and long-term medical monitoring may be necessary to maintain the dog’s health.

Prevention

The prevention of fungal infections of the urinary tract in dogs includes minimizing risk factors and promoting a healthy immune system. A balanced diet and regular veterinary examinations can help strengthen the dog’s immune system and detect health problems early.

It is important to limit the use of antibiotics to what is necessary to maintain a healthy microbial balance in the body. In dogs with chronic diseases that increase the risk of fungal infections, close monitoring and regular medical care should be provided.

Maintaining good hygiene, especially in the dog’s genital area, can also help reduce the risk of infection. Owners should ensure that their dog drinks enough to regularly flush the urinary tract and prevent the accumulation of microorganisms.

Outlook on current research

Fungal infection of the urinary tract refers to a fungal infection of the bladder, ureters, or kidneys, most commonly by Candida species. What is particularly challenging from a professional standpoint is that detection of fungi in the urine does not automatically indicate a true infection: it may only indicate colonization. This distinction is currently one of the most important research areas because it is crucial for therapy decisions. (ncbi.nlm.nih.gov, idsociety.org)

A second focus is on diagnostics. Traditional urine culture remains important but is often insufficient to reliably distinguish colonization, biofilm on catheters, and invasive infections from one another. Therefore, work is being done on molecular detection methods, improved risk models, and more precise integration of microbiology, imaging, and hospital findings. This is particularly relevant in patients with catheters, urinary outflow obstruction, diabetes, or immunosuppression. (idsociety.org, pubmed.ncbi.nlm.nih.gov)

There is also research need in therapy. Not every antifungal reaches sufficiently effective concentrations in the urine or kidney tissue, and resistance development is becoming increasingly relevant. Therefore, research is investigating new strategies against biofilms, better local drug concepts, and individualized treatments depending on fungal species and infection pattern. (idsociety.org, pubmed.ncbi.nlm.nih.gov)

Overall, the outlook is good: development is clearly moving toward more precise diagnosis, more targeted therapy, and better prevention of catheter-associated fungal infections.

Frequently Asked Questions (FAQs)

1. What is a fungal infection of the urinary tract?
A urinary tract mycosis is an infection of the lower urinary tract by fungi, usually Candida species, less commonly Aspergillus, Cryptococcus, or other molds. Candida albicans is the most common pathogen. The condition is overall rare in dogs and primarily affects animals with a weakened immune system or predisposing underlying diseases.
2. Which dogs are at risk?
Risk factors include diabetes mellitus, long-term therapy with antibiotics or corticosteroids, indwelling bladder catheters, hyperadrenocorticism, and structural abnormalities of the urinary tract. Fungal infections can also spread after chemotherapy and in chronic kidney failure.
3. What Symptoms occur?
Often the clinical signs are nonspecific and resemble bacterial cystitis: increased urinary urgency, painful urination, bloody or cloudy urine, and incontinence. However, many dogs are also asymptomatic, especially with pure colonization without true infection.
4. How is the diagnosis made?
Culture of the urine is crucial, ideally from a sterile cystocentesis. Microscopic detection of fungal elements in the sediment and a positive fungal culture confirm the diagnosis. Species identification and, if necessary, an antifungal susceptibility test help with therapy selection.
5. How is a urinary tract mycosis treated?
Therapy is systemic with fluconazole, a highly water-soluble azole that concentrates well in the urine. Treatment duration is usually two to four weeks. For resistant pathogens, itraconazole or local irrigation with diluted clotrimazole solution may be considered.
6. Why are concurrent diseases so important?
Fungal infections rarely develop on healthy ground. An underlying disease such as diabetes mellitus or Cushing's syndrome must be identified and treated, otherwise recurrences occur regularly. Indwelling catheters should also be removed if possible or changed frequently.
7. Is the mycosis transmissible to humans?
The Candida species relevant in dogs also live in humans as mucosal commensals. Direct transmission from dog to human is theoretically possible but clinically very rare. Good hand hygiene after urine handling is sufficient.
8. How do you distinguish colonization from infection?
The mere detection of individual colonies in the urine does not yet mean infection, especially in asymptomatic dogs. Only repeated high colony counts in conjunction with clinical symptoms or signs of inflammation in the sediment justify therapy. In asymptomatic dogs, observation is often sufficient.
9. How is treatment success monitored?
A follow-up urine culture should be performed two to four weeks after the end of therapy to confirm elimination of the pathogen. In persistent infection, extension of therapy, change of antifungal, or search for a remaining underlying cause are considered.
10. What is the prognosis?
In dogs without severe underlying disease, the prognosis is good. In severe immunosuppression, persistent diabetes, or structural urinary tract abnormalities, recurrences are common. Consistent treatment of the underlying disease is crucial for long-term success.

Literature

  • Weese, J. S., & Weese, H. E. (2025). Treatment of fungal urinary tract disease in dogs and cats: A scoping review. Research in Veterinary Science, 192, Article 105710. https://doi.org/10.1016/j.rvsc.2025.105710
  • Reagan, K. L., Dear, J. D., Kass, P. H., & Sykes, J. E. (2019). Risk factors for Candida urinary tract infections in dogs and cats. Journal of Veterinary Internal Medicine, 33(2), 648–653. https://doi.org/10.1111/jvim.15444
  • Jin, Y., & Lin, D. (2005). Fungal urinary tract infections in the dog and cat: A retrospective study (2001–2004). Journal of the American Animal Hospital Association, 41(6), 373–381.
  • Pressler, B. M., Vaden, S. L., Lane, I. F., Cowgill, L. D., & Dye, J. A. (2003). Candida spp. urinary tract infections in 13 dogs and seven cats: Predisposing factors, treatment, and outcome. Journal of the American Animal Hospital Association, 39(3), 263–270. https://doi.org/10.5326/0390263
  • Han, S. M., Chae, H., Kim, D., & Lee, G. (2024). Successful treatment of Candida albicans-induced fungal cystitis in a dog using caspofungin: A case report. Veterinary Research Forum, 15(8), 435–438. https://doi.org/10.30466/vrf.2024.2021058.3941
  • Forward, Z. A., Legendre, A. M., & Khalsa, H. D. S. (2002). Use of intermittent bladder infusion with clotrimazole for treatment of candiduria in a dog. Journal of the American Veterinary Medical Association, 220(10), 1496–1498. https://doi.org/10.2460/javma.2002.220.1496
  • Kim, M., Jung, W. K., Park, Y. K., Lee, S. H., Park, H. E., Lee, H., Choi, J., Lee, H. J., Jeong, D. G., Kim, J.-M., & Kim, M. (2017). Azole resistance caused by increased drug efflux in Candida glabrata isolated from the urinary tract of a dog with diabetes mellitus. Mycobiology, 45(4), 349–353. https://doi.org/10.5941/MYCO.2017.45.4.349