Few topics stir as much debate among lactation professionals as “nipple thrush.” Some clinicians see it frequently, while others doubt whether Candida albicans is the true culprit of nipple and breast pain. What is certain is that pain during breastfeeding can be severe, disruptive, and a risk factor for early weaning. Understanding the biology of Candida, its risk factors, and the complexities of diagnosis will help lactation professionals guide families with clarity and evidence.

What Is Candida albicans?

Candida albicans is a yeast that normally lives in the human microbiome, colonizing the mouth, gut, vagina, and skin without causing symptoms (Koparal et al., 2023). In healthy hosts, it exists as a harmless commensal. Under certain conditions—such as after antibiotics or when the immune system is compromised—it can switch from a benign yeast form to an invasive hyphal form, causing infection.

This morphologic flexibility, combined with adhesive proteins, biofilm formation, and tissue-damaging enzymes, makes C. albicans a highly adaptable organism capable of causing mucosal infections like thrush.

What Causes Candida Overgrowth?

Thrush arises when the balance between host defenses, bacterial flora, and yeast is disrupted. Risk factors include:

• Maternal or infant antibiotics: Strongly associated with yeast overgrowth. Infants of mothers on antibiotics for more than one week had triple the odds of thrush in one study (Mackawy et al., 2025).

• Nipple trauma: Cracks or abrasions provide entry points for yeast (Amir et al., 2013).

• Moisture: Yeast thrives in warm, damp environments, such as under breast pads, or on pacifiers and nipple shields (Lawrence & Lawrence, 2022).

• Maternal health: Diabetes, vaginal candidiasis, immunosuppression, or corticosteroid use increase susceptibility (Koparal et al., 2023).

• Infant colonization: Because yeast readily lives in the infant’s mouth or diaper area, infants can reinfect their mothers.

Is Candida Contagious?

Yes—but not in the way a cold or flu virus spreads. C. albicans is an opportunistic pathogen that can move back and forth between mother and infant, creating a cycle of reinfection (Brent, 2001).

• At birth: Infants can acquire yeast during vaginal delivery from colonized mothers.

• During breastfeeding: Thrush in an infant’s mouth can spread to the nipple, while a mother’s nipple infection can seed yeast back into the infant’s oral cavity (Amir et al., 2013).

• Via objects: Pacifiers, bottle nipples, and breast pump parts may harbor yeast if not sterilized properly (Lawrence & Lawrence, 2022).

Because of this bidirectional transmission, experts stress that both mother and baby should be treated together, even if only one shows obvious symptoms (Brent, 2001). Otherwise, reinfection is likely.

Clinical Presentation

In mothers, thrush may cause:

• Deep, burning, or radiating pain during and after feeds.

• Pink, shiny, or flaky nipples, with or without itching.

• Normal-appearing nipples despite severe pain.

In infants, signs may include:

• White plaques on the tongue or oral mucosa that do not scrape off.

• Irritability at the breast or refusal to feed.

• Diaper rash with red lesions and satellite spots.

Symptoms vary, and both mother and infant may sometimes be asymptomatic.

The Impact on Breastfeeding

When symptomatic, thrush can cause burning nipple pain, radiating or shooting pain into the breast, erythema, and shiny or flaky nipples. For infants, oral thrush may present as white plaques on the tongue or buccal mucosa and can interfere with effective suckling (Lawrence & Lawrence, 2022). The impact is significant: mothers with mammary candidiasis have been shown to wean at 2.2 times the rate of unaffected mothers by 9 weeks postpartum (Hale, Bateman, Finkelman, Berens, & Howard, 2009). Pain and ineffective feeding can undermine maternal confidence and shorten breastfeeding duration.

Prevalence of Thrush

Reported prevalence of nipple and breast thrush varies widely, partly due to challenges in diagnosis. Some studies suggest that up to 20% of lactating women may be affected (Mackawy et al., 2025). In the prospective CASTLE cohort, 19% of women reported concurrent burning nipple pain and non-mastitis breast pain within the first 8 weeks postpartum (Amir et al., 2013). Laboratory confirmation, however, is inconsistent. Conventional culture detects Candida in only a small percentage of cases, whereas polymerase chain reaction (PCR) has identified yeast colonization in nearly one-third of symptomatic women (Panjaitan, Amir, Costa, Rudland, & Tabrizi, 2008).

Diagnosis: Why It’s Complicated

Thrush is difficult to diagnose with certainty. Standard swabs and cultures often fail to confirm Candida, and colonization can occur without symptoms (Amir et al., 2013; Panjaitan et al., 2008).

Recent studies have also questioned the yeast hypothesis altogether. A Spanish cohort study found that coagulase-negative staphylococci and streptococci—not Candida—were most often present in painful dyads, suggesting many “thrush” cases are actually subacute mastitis (Jiménez et al., 2017). Betts et al. (2021) reported that none of the 25 women treated for presumed thrush had Candida; alternative diagnoses such as dermatitis, nipple blebs, or vasospasm explained their symptoms.

For lactation professionals, this means a broad differential is key. Not every burning nipple is yeast.

Management and Treatment

When thrush is suspected:

• Treat the dyad: Both mother and infant should receive therapy.

• Topical antifungals: Nystatin suspension for the infant; miconazole or clotrimazole for the mother’s nipples.

• Oral antifungals: For persistent or severe cases, fluconazole for the mother may be prescribed.

• Supportive care: Optimize latch and positioning, sterilize pump parts, replace pacifiers, wash hands, and change breast pads frequently.

Crucially, thrush is not a reason to stop breastfeeding. With proper treatment and support, lactation can continue uninterrupted (Lawrence & Lawrence, 2022).

Controversies and Misdiagnosis

The diagnosis of thrush remains controversial. While many clinicians strongly associate persistent nipple and breast pain with Candida infection, others argue that the evidence is weak. For example, Betts, Johnson, Eglash, and Mitchell (2021) found that women diagnosed with “mammary candidiasis” who did not improve with antifungals were more accurately diagnosed with subacute mastitis, dermatitis, vasospasm, nipple blebs, or hyperlactation, and none had confirmed Candida.

Some researchers have further argued that antifungal medications may improve symptoms not due to antifungal activity, but because of their anti-inflammatory properties (Jiménez et al., 2017). Major references such as Breastfeeding: A Guide for the Medical Profession caution that deeper “ductal candidiasis” remains an unproven concept, with no definitive evidence linking yeast to deep breast pain (Lawrence & Lawrence, 2022).

Key Takeaways

• Candida albicans is a commensal yeast that can opportunistically cause thrush.

• Risk factors include antibiotics, nipple trauma, moisture, maternal health conditions, and infant colonization.

• Mothers and infants can pass yeast back and forth during breastfeeding, so both must be treated.

• Clinical signs include burning nipple pain, shiny or flaky skin, and oral plaques in infants—but symptoms vary.

• Pain can seriously undermine breastfeeding, regardless of the cause.

• Diagnosis is controversial: many cases labeled as “thrush” are actually bacterial or non-infectious conditions.

• Management requires simultaneous treatment of mother and infant, supportive hygiene, and ongoing breastfeeding.

References

Amir, L. H., Donath, S. M., Garland, S. M., Tabrizi, S. N., Bennett, C. M., Cullinane, M., & Payne, M. S. (2013). Does Candida and/or Staphylococcus play a role in nipple and breast pain in lactation? BMJ Open, 3(3), e002351. https://doi.org/10.1136/bmjopen-2012-00235

Betts, R. C., Johnson, H. M., Eglash, A., & Mitchell, K. B. (2021). It’s not yeast: Retrospective cohort study of lactating women with persistent nipple and breast pain. Breastfeeding Medicine, 16(4), 318–324. https://doi.org/10.1089/bfm.2020.0160

Betzold, C. M. (2010). An update on the recognition and management of lactational breast inflammation. Journal of Midwifery & Women’s Health, 52(6), 595–605. doi: 10.1016/j.jmwh.2007.08.002.

Brent, N. B. (2001). Thrush in the breastfeeding dyad: Results of a survey on diagnosis and treatment. Clinical Pediatrics, 40(9), 503–506. https://doi.org/10.1177/00099228010400090

Jiménez, E., Arroyo, R., Cárdenas, N., Marín, M., Serrano, P., Fernández, L., & Rodríguez, J. M. (2017). Mammary candidiasis: A medical condition without scientific evidence? PLoS ONE, 12(7), e0181071. https://doi.org/10.1371/journal.pone.0181071

Koparal, M., Muluk, N. B., & Barsova, G. K. (2023). Candidiasis during breastfeeding. In Ö. N. Şahin (Ed.), Breastfeeding and metabolic programming (pp. 603–612). Springer. https://doi.org/10.1007/978-3-031-33278-4_50

Lawrence, R. A., & Lawrence, R. M. (2022). Breastfeeding: A guide for the medical profession (9th ed.). Elsevier.

Mackawy, A. M., et al. (2025). The impact of maternal antibiotic consumption on the development of oral thrush infection in infants. International Journal of Pediatrics and Adolescent Medicine, 12(1), 34–41.

Panjaitan, M., Amir, L. H., Costa, A. M., Rudland, E., & Tabrizi, S. (2008). Polymerase chain reaction in detection of Candida albicans for confirmation of clinical diagnosis of nipple thrush. Breastfeeding Medicine, 3(3), 185–191. https://doi.org/10.1089/bfm.2008.0106