Candida infections of the breast are often under-recognised in breast-feeding women, and have received little study.1 Often, thrush may be diagnosed in the baby but not in the mother.1 Signs of thrush in the mother are sore, pink or itchy nipples (not necessarily with white patches), inflammation of the nipple and/or areola, and burning sensations or shooting pains deep in the breast, between or during feeds.1,2 Signs of thrush in the infant are white patches on his gums, cheeks, palate, tonsils or tongue, a white sheen on inside of lips or the saliva, nappy rash, feed refusal (due to having a sore mouth).
Women should be reassured that breast-feeding can continue, provided that the thrush (candidiasis) is treated. 1–3 Feeding may be more comfortable if the baby feeds on the least painful side first, and if the mother is very careful when breaking baby’s suction during or at the end of a feed. 
When thrush is suspected, it is essential to treat both the mother and infant (and often the father too), even if no symptoms are observed in the baby’s mouth. Failure to treat the baby may prolong the infection or encourage repeat episodes. This is also the case for any vaginal yeast infection (which should be treated simultaneously, under the care of the GP). Treatment with oral agents (fluconazole for the mother; fluconazole or nystatin for the infant) can be considered.2,3Thrush is more likely to occur in mothers receiving antibiotics, or mothers with poorly controlled diabetes or immunodeficiencies; use of oestrogen-containing contraceptives or corticosteroids are possibly associated with thrush.4 Studies have not been undertaken to confirm whether restricting sugary or yeast-containing foods, or taking probiotic supplements, have any effect on the incidence of breast candidiasis.

References1.  Brent NB. Thrush in the breastfeeding dyad: results of a survey on diagnosis and treatment. Clin Pediatr (Phila) 2001; 40: 503–506

2. Shepherd J. Thrush and breastfeeding. Pract Midwife 2002; 5: 24–27.

3. Chetwynd EM. Fluconazole for postpartum candidal mastitis and infant thrush. J Hum Lact 2002; 18: 168–171.

4. NHS Clinical Knowledge Summaries. Accessed 12 Nov 2009.

From: Journal of Family Health Care Bulletin. Directory of Breast-Feeding Advice. December 2009. Published with JFHC 2009; 19(6).