What is the first line treatment for oral thrush in infants?

Treatment and Diagnosis of Oral Thrush in Babies

First-Line Treatment

Nystatin oral suspension is the first-line treatment for oral thrush in otherwise healthy infants, administered as 2 mL (200,000 units) four times daily, with the dropper placing one-half of the dose in each side of the mouth, avoiding feeding for 5-10 minutes. 1

Dosing Specifics by Age

• Premature and low birth weight infants: 1 mL four times daily is effective 1
• Standard infants: 2 mL (200,000 units) four times daily 1
• Duration: Continue for at least 48 hours after symptoms disappear and cultures confirm eradication of Candida albicans 1

Administration Technique

• Use dropper to place medication directly on oral lesions 1
• Retain preparation in mouth as long as possible before swallowing 1
• Avoid feeding for 5-10 minutes after administration to maximize contact time 1

Alternative First-Line Treatment

Fluconazole 3-6 mg/kg once daily for 7 days is superior to nystatin and should be considered as first-line therapy, particularly when nystatin fails or compliance is challenging. 2, 3

Evidence Supporting Fluconazole

• Clinical cure rates: fluconazole 100% vs. nystatin 32% in head-to-head comparison 3
• Once-daily dosing improves compliance compared to nystatin's four-times-daily regimen 3
• Half-life of 55-90 hours in neonates supports once-daily administration 2

When to Choose Fluconazole Over Nystatin

• Treatment failure with nystatin after 5-7 days 2
• Compliance concerns with four-times-daily dosing 3
• Recurrent thrush despite adequate nystatin treatment 4
• Moderate to severe disease requiring more reliable cure rates 3

Miconazole Oral Gel: Use with Extreme Caution

Miconazole oral gel (15 mg four times daily) demonstrates superior efficacy to nystatin but carries significant risk of airway obstruction in infants and should be avoided. 5, 6

Why Miconazole Should Be Avoided

• Risk of asphyxiation: Documented near-fatal airway obstruction in neonates due to viscous gel consistency 6
• Concerns for triazole resistance: Potential to generate resistant Candida species 7
• Guideline recommendation against use: ESCMID guidelines grade miconazole as D-II (should not be used) 7

Despite showing 84.7% cure rate by day 5 versus 21.2% for nystatin 5, the safety concerns outweigh efficacy benefits in routine practice.

Diagnosis of Oral Thrush

Clinical Presentation

• White, curd-like plaques on tongue, buccal mucosa, or palate that do not wipe off easily 4
• Erythematous base when plaques are removed 4
• Feeding difficulties or fussiness during feeds may be present 4

Confirmation

• Clinical diagnosis is usually sufficient in typical cases 4
• Culture confirmation should be obtained if diagnosis is uncertain or treatment fails 1
• Consider underlying conditions if thrush is recurrent or treatment-resistant (immunodeficiency, diabetes, chronic steroid use) 4, 8

Special Populations

High-Risk Neonates (Birth Weight <1000g)

In nurseries with invasive candidiasis rates >10%, prophylactic fluconazole 3-6 mg/kg twice weekly for 6 weeks is recommended. 7, 2

• This prevents progression to invasive candidiasis in extremely low birth weight infants 7
• Prophylaxis should be considered on individual basis in units with lower incidence 7

Immunocompromised Children

Systemically absorbed antifungals (fluconazole or itraconazole) should be used when risk of dissemination exists. 4

• Non-absorbed agents (nystatin) are insufficient when immunodeficiency is present 4
• Consider evaluation for underlying immunodeficiency if thrush is severe, recurrent, or treatment-resistant 8

Treatment Failure Algorithm

If No Improvement After 5-7 Days of Nystatin:

1. Switch to fluconazole 3-6 mg/kg once daily 2, 3
2. Verify compliance with administration technique and frequency 1
3. Assess for reinfection source: maternal breast candidiasis, contaminated bottle nipples, pacifiers 4

If No Improvement After Fluconazole:

1. Obtain culture to confirm Candida species and rule out resistant organisms 1
2. Evaluate for underlying immunodeficiency or predisposing conditions 8
3. Consider systemic candidiasis if infant appears ill or has risk factors 7

Common Pitfalls to Avoid

• Inadequate contact time: Nystatin must remain in contact with oral mucosa; avoid immediate feeding 1
• Premature discontinuation: Continue treatment 48 hours after symptom resolution 1
• Ignoring reinfection sources: Treat maternal breast candidiasis, sterilize pacifiers and bottle nipples 4
• Using miconazole gel in young infants: Risk of airway obstruction outweighs benefits 6
• Missing underlying conditions: Persistent or recurrent thrush warrants investigation for immunodeficiency 8