What is the ICD-10 code and treatment for oral candidiasis (fungal infection in the mouth) caused by Candida?

ICD-10 Code and Treatment for Oral Candidiasis

ICD-10 Code

The ICD-10 code for oral candidiasis (thrush) is B37.0 for candidal stomatitis, which covers fungal infections of the mouth caused by Candida species 1, 2, 3.

First-Line Treatment Algorithm

For Mild Oral Candidiasis

Oral fluconazole 100-200 mg daily for 7-14 days is the most effective first-line treatment, superior to topical agents in efficacy and convenience 4, 5. This recommendation is based on multiple randomized controlled trials showing fluconazole's superiority over topical therapies 4.

Alternative topical options for mild disease include:

• Clotrimazole troches: 10 mg dissolved in mouth 5 times daily for 7-14 days 4, 6, 5
• Nystatin suspension: 4-6 mL (400,000-600,000 units) swished in mouth and swallowed 4 times daily for 7-14 days 4, 6, 1
• Miconazole mucoadhesive buccal tablet: 50 mg applied once daily for 7-14 days 4, 5

Important caveat: Topical agents like nystatin have significantly lower efficacy (32-54% cure rates) compared to fluconazole (approaching 100% in many studies), and should be reserved only for very mild cases or when systemic therapy is contraindicated 4, 6.

For Moderate to Severe Disease

Oral fluconazole 200 mg daily for 14-21 days is the definitive treatment 4, 5. For patients unable to swallow, intravenous fluconazole 200-400 mg daily should be used 4, 6.

For Esophageal Candidiasis

Topical therapy is completely ineffective for esophageal involvement 4. Treatment requires:

• Oral fluconazole 200 mg daily for 14-21 days (first-line) 4
• Itraconazole solution 200 mg daily (alternative) 4, 7
• IV therapy if unable to swallow 4, 6

Treatment for Refractory or Recurrent Cases

Second-Line Options (Fluconazole-Refractory Disease)

When fluconazole fails after adequate treatment duration:

• Itraconazole oral solution 200 mg daily: Effective in 64-80% of fluconazole-refractory cases; must be swished in mouth before swallowing 4, 6, 7
• Posaconazole suspension 400 mg twice daily: Approximately 75% efficacy in refractory cases 4, 5
• Voriconazole 200 mg twice daily: Effective alternative for refractory disease 4, 5, 8

Third-Line Options (Azole-Refractory Disease)

For cases failing all azole therapy:

• Echinocandins (IV only): Micafungin 150 mg daily, caspofungin 70 mg loading then 50 mg daily, or anidulafungin 200 mg daily 4, 6
• Amphotericin B deoxycholate 0.3-0.7 mg/kg IV daily: Reserved as last resort due to toxicity 4, 6, 5

Critical Management Considerations

Treatment Duration

Continue therapy for the full 7-14 days even if symptoms resolve earlier 4, 6, 5. For esophageal candidiasis, extend treatment for at least 2 weeks after symptom resolution 4, 7.

Special Populations and Situations

HIV/AIDS patients:

• Initiate or optimize antiretroviral therapy (HAART) immediately—this is more important than antifungal choice for preventing recurrence 4, 5
• For recurrent infections: Fluconazole 100-200 mg three times weekly as chronic suppressive therapy 4, 5
• Primary prophylaxis is NOT recommended despite efficacy, due to drug interactions, cost, and resistance concerns 4

Denture-related candidiasis:

• Denture disinfection is mandatory alongside antifungal therapy; failure to disinfect dentures will result in treatment failure 6, 5, 3
• Remove dentures at night and soak in chlorhexidine or other disinfectant 4, 2

Immunocompromised patients:

• Avoid topical agents; use systemic fluconazole from the outset 4, 6
• Higher risk of azole-refractory disease with repeated azole exposure 4

Common Pitfalls to Avoid

1. Do not rely on fungal cultures for diagnosis: Candida is a normal oral commensal in 40-65% of healthy adults; diagnosis is clinical, confirmed by response to therapy 4, 2, 9

2. Do not use nystatin or other topical agents for moderate-severe disease or immunocompromised patients: These have unacceptably low cure rates and poor tolerability (bitter taste, frequent dosing) 4, 6

3. Do not use itraconazole capsules: Poor oral absorption makes them ineffective; only itraconazole solution is recommended 4

4. Do not use ketoconazole: Inferior efficacy to fluconazole and significant hepatotoxicity risk 4, 2

5. Do not stop treatment when symptoms improve: Premature discontinuation leads to recurrence 4, 6, 5

6. Do not forget to assess for underlying predisposing factors: Diabetes, xerostomia, inhaled corticosteroids, broad-spectrum antibiotics, and immunosuppression must be addressed 2, 3, 9