What is the cause of recurrent oral candidiasis (thrush) in a 23-month-old child after two courses of Nystatin (nystatin)?

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Last updated: April 23, 2025View editorial policy

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From the Guidelines

For recurring thrush in a 23-month-old after two courses of nystatin, I strongly recommend switching to fluconazole oral suspension, 100-200 mg daily, for 7-14 days, as it is a more effective treatment for moderate to severe disease, according to the 2016 update by the Infectious Diseases Society of America 1. This recommendation is based on the high-quality evidence that supports the use of fluconazole for the treatment of candidiasis, especially in cases where nystatin has failed to resolve the infection. Some key points to consider in the management of recurring thrush in this patient include:

  • Good oral hygiene practices, such as gently wiping the child's mouth with a clean, damp cloth after feedings and sterilizing pacifiers, bottles, and toys that go in the mouth.
  • Identifying and addressing any underlying issues that may be contributing to the recurring infection, such as an immune system concern, persistent source of reinfection, or resistance to nystatin.
  • Considering the potential impact of antibiotics on the child's oral flora and the possible need to treat the mother's nipples with an antifungal cream if the child is breastfed.
  • Dietary changes, such as temporarily reducing sugary foods and drinks, may also help to promote a healthy oral environment and prevent yeast growth. It is essential to consult a pediatrician for further evaluation and guidance on the best course of treatment for this patient, as recurring thrush can be a sign of an underlying issue that needs to be addressed. The use of fluconazole as an alternative treatment is supported by the clinical practice guideline for the management of candidiasis, which recommends oral fluconazole, 100-200 mg daily, for 7-14 days, for moderate to severe disease 1.

From the FDA Drug Label

CLINICAL PHARMACOLOGY Microbiology Nystatin is both fungistatic and fungicidal in vitro against a wide variety of yeasts and yeast-like fungi. Candida albicans demonstrates no significant resistance to nystatin in vitro on repeated subculture in increasing levels of nystatin; other Candida species become quite resistant.

The child may have a resistant Candida species or inadequate treatment. Consider re-evaluating the diagnosis or consulting a specialist for further guidance. 2

From the Research

Recurring Thrush in a 23-Month-Old

  • The child has undergone two courses of nystatin for thrush, which suggests that nystatin may not be effective in treating the condition 3, 4.
  • Studies have shown that fluconazole is more effective than nystatin in treating oral thrush in infants and children 3, 4.
  • In one study, fluconazole was shown to have a clinical cure rate of 100% compared to 32% for nystatin in treating oral candidiasis in infants 3.
  • Another study found that fluconazole was more effective than nystatin in treating oropharyngeal candidiasis in immunocompromised children, with a clinical cure rate of 91% compared to 51% for nystatin 4.

Possible Causes of Recurring Thrush

  • Recurring thrush can be caused by various factors, including immunodeficiency or autoimmune disorders 5.
  • In some cases, recurring thrush can be a symptom of an underlying condition, such as autoimmune polyendocrinopathy syndrome type 1 (APS-1) 5.
  • It is essential to consider other possible causes of recurring thrush beyond immunodeficiency, as seen in the case of a child with APS-1 who presented with recurrent oral thrush 5.

Alternative Treatments

  • Capric acid has been shown to have antifungal activity against Candida isolates, although its effectiveness is lower than that of fluconazole and nystatin 6.
  • The combination of capric acid with fluconazole or nystatin may be effective against resistant isolates, although the interactions between these agents can be synergistic, indifferent, or antagonistic 6.
  • Fluconazole has been shown to be effective in preventing candida infections in children undergoing chemotherapy, and may be a suitable alternative to nystatin in some cases 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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