What is the treatment for a 4-week-old female infant with a yeast infection?

Treatment of Yeast Infection in a Four-Week-Old Female Infant

For a four-week-old female infant with a yeast infection (candidal diaper rash), topical nystatin cream or ointment applied to the affected area with each diaper change is the recommended first-line treatment. 1

Assessment and Diagnosis

Before initiating treatment, confirm the diagnosis by examining:

• Characteristic bright red, well-demarcated rash with satellite lesions
• Involvement of skin folds
• Presence of concurrent oral thrush (white patches in mouth)

Treatment Algorithm

First-Line Treatment

• Topical antifungal therapy:
  • Nystatin cream or ointment applied to affected areas with each diaper change for 7-14 days 1
  • Continue treatment for at least 48-72 hours after the rash resolves to prevent recurrence

For Concurrent Oral Thrush

• Add oral nystatin suspension 1 mL (100,000 units) four times daily 1
• Administer after feeds by applying to the inside of cheeks
• Continue for at least 48 hours after symptoms resolve

For Severe or Persistent Infection

• If no improvement after 3 days of topical therapy, consider:
  • Amphotericin B deoxycholate 1 mg/kg daily (for systemic infection) 2
  • Fluconazole 12 mg/kg daily (if no prior fluconazole exposure) 2

Supportive Measures

• Keep the diaper area clean and dry
• Change diapers frequently
• Allow for diaper-free time to promote air circulation
• Avoid occlusive barrier creams that may promote fungal growth 1
• Address underlying causes such as gastroesophageal reflux if present

Special Considerations

Warning Signs for Systemic Infection

Monitor for signs of systemic infection, especially in premature or low birth weight infants 2:

• Persistent fever
• Feeding intolerance
• Lethargy
• Persistent positive cultures

If systemic infection is suspected:

• Perform blood cultures, lumbar puncture, and urine culture 2
• Consider imaging of genitourinary tract, liver, and spleen 2
• Initiate systemic antifungal therapy promptly

Cautions

• Echinocandins should be used with caution in infants and generally limited to salvage therapy 2
• Fluconazole should be used cautiously in infants less than 6 months of age due to limited efficacy data 3
• Monitor for potential side effects of systemic antifungals

Follow-up

• Evaluate response to therapy after 2-3 days of treatment
• If no improvement is seen, reassess diagnosis and consider alternative antifungal agents 1
• For systemic infections, continue therapy for 2 weeks after documented clearance of Candida from bloodstream 2

By following this treatment approach, most infants with candidal infections will respond well to therapy with minimal risk of complications or progression to systemic disease.