What is the diagnosis and treatment for a patient presenting with white plaques on the tongue that can be scraped off and leave a red base, suggestive of oral thrush?

Diagnosis and Treatment of Oral Thrush

Diagnosis

The clinical presentation of white plaques on the tongue that can be scraped off leaving a red base is diagnostic of oropharyngeal candidiasis (oral thrush), and diagnosis is typically made on clinical grounds without requiring laboratory confirmation. 1, 2

Clinical Features

• Pseudomembranous candidiasis presents as painless, creamy white, plaque-like lesions on the buccal mucosa, oropharyngeal mucosa, or tongue surface that can be easily scraped off with a tongue depressor 1
• The key distinguishing feature from oral hairy leukoplakia is the ability to scrape off the superficial whitish plaques 1
• Less commonly, erythematous patches without white plaques may appear on the palate or tongue 1
• Angular cheilitis may also be present 1

When Laboratory Confirmation is Needed

• Laboratory confirmation is only required for refractory or recurrent cases 1
• A scraping for microscopic examination using potassium hydroxide (KOH) preparation can demonstrate yeast forms 1
• Culture on fungal selective media identifies the Candida species and allows susceptibility testing 1
• Species identification and susceptibility testing are specifically recommended for patients repeatedly exposed to fluconazole 1

Critical Assessment Points

• Evaluate for immunosuppression, particularly HIV infection with CD4+ counts <200 cells/µL 1, 3
• Assess for predisposing factors: corticosteroid use (including inhaled steroids), broad-spectrum antibiotics, xerostomia, smoking, alcohol consumption, and denture use 3, 4
• Screen for esophageal involvement if the patient reports odynophagia, retrosternal burning pain, or dysphagia, as this occurs in 10-20% of cases and requires different management 1, 2

Treatment

First-line therapy is fluconazole 200-400 mg (3-6 mg/kg) orally daily for 7-14 days, which achieves clinical response rates of 80-90%. 2

First-Line Systemic Therapy

• Fluconazole 200-400 mg daily for 7-14 days is the preferred treatment for most cases 2
• Clinical response (cured or improved) averages 84-86% across controlled trials 5
• The 14-day regimen is associated with lower relapse rates than 7-day therapy 5

Topical Therapy Options

Topical agents are appropriate for mild cases or when systemic therapy is contraindicated 2:

• Clotrimazole troches 10 mg dissolved slowly in the mouth 5 times daily 2
• Nystatin suspension (swish and swallow) or pastilles multiple times daily 2
• Miconazole 50 mg mucoadhesive buccal tablets once daily 2

Refractory Cases

For patients who fail fluconazole or have fluconazole-resistant organisms 2, 5:

• Itraconazole oral solution 200 mg daily (response rate 64-80%) 2, 5
• Posaconazole suspension 2
• Voriconazole (response rate 75%) 2
• In one study of fluconazole-unresponsive HIV patients, itraconazole oral solution 100 mg twice daily achieved complete resolution in 55% of cases 5

Special Populations and Circumstances

HIV-Infected Patients:

• Antiretroviral therapy is the most important intervention to reduce recurrent infections and is the best prophylaxis against oral thrush 1, 3, 2
• Primary antifungal prophylaxis is not recommended despite proven efficacy, due to concerns about drug resistance, drug-drug interactions with antiretroviral therapy, cost, and toxicity 1
• For frequent recurrences despite adequate antiretroviral therapy, fluconazole 100 mg three times weekly as suppressive therapy (efficacy 80-90%) 2

Denture-Related Candidiasis:

• Denture disinfection is essential in addition to antifungal therapy (efficacy 90%) 2
• Proper denture hygiene and removal at night prevents recurrence 2

Common Pitfalls and How to Avoid Them

Resistance Development

• Prolonged or repeated fluconazole courses lead to resistance in 10-20% of immunocompromised patients 2
• Fluconazole resistance is predominantly the consequence of previous exposure, particularly repeated and long-term use 1, 3
• Non-albicans Candida species (particularly C. glabrata) emerge with intrinsic reduced azole susceptibility after repeated antifungal exposure in 5-10% of cases 1, 3, 2

Failure to Address Underlying Causes

• Treatment failure occurs in 20-30% when predisposing factors are not addressed 2
• Always identify and manage: immunosuppression, inhaled corticosteroids, broad-spectrum antibiotics, xerostomia, smoking, alcohol use, and denture hygiene 3, 4

Missing Esophageal Extension

• Esophageal candidiasis should be suspected in patients with oral thrush who report odynophagia, retrosternal pain, or dysphagia (incidence 10-20%) 2
• Esophageal involvement requires endoscopic diagnosis and typically longer treatment duration 1
• Several patients in clinical trials developed esophageal symptoms while receiving therapy for oral disease alone 5

Inadequate Treatment Duration

• Most women will deliver before serologic response can be assessed in pregnancy-related syphilis, but this is irrelevant to candidiasis management 1
• Ensure 14-day therapy rather than 7-day to reduce relapse rates 5
• Of patients who respond and discontinue treatment, relapse occurs in approximately 23% within 4 weeks 5