Veterinary Guide to Fungal Lower Urinary Tract Infection in Dogs (2025)🐶

By Dr. Duncan Houston BVSc

🔍 What Are They?

Fungal UTIs in dogs are most often caused by overgrowth of Candida species in the bladder or urethra. They’re unusual, typically occurring in immunocompromised dogs or those with predisposing factors like antibiotics or urinary catheters.

💡 Risk Factors

• Prolonged or broad-spectrum antibiotic use
• Corticosteroid therapy or systemic immunosuppression
• Structural urinary tract issues—catheters, stones, congenital anomalies
• Concurrent illnesses—diabetes, Cushing’s disease, kidney failure

🚨 Signs & Clinical Features

• May be asymptomatic or mimic bacterial UTI: straining, frequent or hesitant urination, blood/cloudy/foul-smelling urine
• Often discovered during evaluation for another condition or after failed antibiotic therapy
• Possible systemic signs of infection: fever, lethargy, abdominal pain

🔬 Diagnostic Approach

• ✅ Urinalysis & Culture: Obtain via cystocentesis—look for yeast, pyuria, and confirm with fungal culture
• 🖥️ Ultrasound: Check for fungal “bezoars” in bladder/collecting system—hyperechoic non-shadowing masses on ultrasound (see images)
• 🧪 Consider blood/urine cultures and systemic workup if disseminated infection is suspected

🛠 Treatment Strategy

• 🏥 Address underlying causes: Discontinue unnecessary antibiotics/catheters, optimize immune status
• 💊 Fluconazole therapy: First-line oral antifungal—treat for at least 7–14 days; duration may be extended based on culture and imaging
• 🔬 Systemic antifungals: Consider itraconazole or amphotericin B in severe or refractory cases
• 🧽 Supportive care: Ensure optimal hydration, bladder flushing if needed, and treat signs of cystitis
• 🧷 Remove obstacles: Surgically address bladder stones or fungomas obstructing urine flow

📈 Prognosis & Monitoring

• Generally good if treated early with fluconazole and causes reversal
• Monitor via repeat urine cultures and ultrasound to confirm fungal clearance
• If systemic spread occurs (e.g., kidneys), the prognosis becomes guarded and may require prolonged therapy and specialist care

🛡 Prevention & Owner Tips

• Minimize broad-spectrum antibiotic use, and use targeted culture-guided therapy
• Limit urinary catheter use and ensure sterile techniques
• Manage chronic diseases like diabetes and Cushing's effectively
• Encourage frequent urination and bladder hygiene

🔧 Owner Tools & Support Services

• Ask A Vet App: 24/7 guidance on symptoms, urine collection techniques, and therapy monitoring 📱

✅ Final Thoughts

Fungal urinary infections in dogs, while uncommon, require thorough diagnosis and targeted antifungal treatment. With timely intervention—especially fluconazole therapy—and correction of predisposing factors, the prognosis is generally favourable. Follow-up with urine cultures and ultrasound ensures complete resolution. In 2025, use Ask A Vet through treatment and recovery. 🐾❤️

Download the Ask A Vet app today for expert help with fungal UTI diagnosis, treatment steps, and follow‑up monitoring. 📱💡