Causes of Nipple and Breast Infections

by Dr. Jane A. Morton


The past few years have brought many changes which ultimately increase the risks for a mother of developing a nipple infection or mastitis, a breast infection. A recent study reported a rate of 17.4% for mastitis in the first postpartum year, with 41% of cases occurring in the first month postpartum. (Vogel A, et al "Mastitis in the First Year Postpartum" Birth, 1999; 26:218-25) To better appreciate this, we first need to understand the causes and consequences of an infection.

The recipe for mastitis is:

• the "germ"
• portal of entry
• culture medium
• supportive environment

The "germ" Bacterial mastitis is most frequently caused by staphylococcal aureus, a common inhabitant on the skin and nasal mucosa. Candida albicans , a fungus and a less common "bug" causing breast infections , is a member of the normal intestinal flora. (Heinig M J, et al "Mammary Candidosis In Lactating Women" J. Hum. Lact 1999;15:281-288.) Infants normally become colonized with Candida over the first few weeks of life.

The portal of entry can be the ducts in the nipple, and very commonly, sore or cracked nipples.

The perfect culture medium is sugary breastmilk.

The ideal environment for growth of both bacteria and fungi is "the tropics"—a warm, moist area.

The consequences of nipple infections and mastitis are not only the pain and malaise for the mother, but there may also be an abrupt and irreversible reduction in her milk supply, if not treated appropriately.

What recent changes in our lifestyle and hospital practices contribute to the risks for infection? Lets start at the beginning, the birth.

Antibiotic Use During Delivery May Contribute to Yeast Infections
With our growing appreciation for the risks to the newborn of an infection of the blood by a bacteria called Group B streptococcus, neonatologists and infectious disease specialists are designing and revising protocols to treat mothers and babies who have certain risk factors. Though this is still a murky area, because the disease can be so devastating, we are throwing our nets widely to save a significant, yet relatively small number of affected babies. Importantly, this has reduced the incidence of this life-threatening disease by over 60%. However, with these protocols, more mothers and babies are receiving antibiotics. Antibiotics change the normal balance of flora on the skin and in the intestine, making the overgrowth of a fungus such as Candida albicans more likely. In one study, 73% of women reported taking an antibiotic 2-4 weeks before the diagnosis of a yeast breast infection. (Tanguay K E, et al, "Nipple Candidiasis Among Breastfeeding Mothers" Can Fam Physician 1994; 40:1407-1413.)

Does An Epidural Add to the Risk?
One of the "risk factors" that would lead to the use of antibiotics would be a fever that develops during labor. The concern is that fever may indicate an infection of the placenta and membranes around the baby, possibly due to Group B streptococcus. But a recent study showed frequently the fever during term labor may not be due to infection but rather the consequence of the use of epidural analgesia. Specifically, the rate of fever in mothers with an epidural was 16.6% in contrast to the 0.6% in mothers not receiving analgesia for pain relief. They also found that the infants of the febrile mothers were more likely to have low I-minute Apgar scores, to require bag and mask resuscitation, and to require oxygen therapy in the nursery.(Lieberman E, Lang J, et al "Intrapartum Maternal Fever and Neonatal outcome" Pediatrics 2000;105:8-13) These signs could also suggest infection in the baby. Thus, the use of an epidural may contribute to the use of what is called "intrapartum antibiotics for Group B strep", and thereby the temporary disruption of the normal flora.

Poor Latch-on = Sore Nipples, the Gateway for Infection
With the constraints on hospital budgets, another evolving reality for most hospitals is to require nurses to care for a larger panel of patients. This can translate into less time for mothers to receive help with breastfeeding, especially the important learning of how to help a baby latch onto the breast well. The most common cause of sore, abraded and cracked nipples is not from nursing too long but from nursing "wrong", meaning the nipple is not positioned far enough back in the baby’s mouth to avoid the trauma of his tongue, hence the development of the perfect portal of entry. In a recent study, mastitis developed in 12% to 35% of mothers with cracked nipples not treated with systemic antibiotics, compared to 5% who were treated. (Livingston V et al "The Treatment of Staphyloccocus Aureus infected Sore Nipples: A Randomized Comparative Study" J. Hum. Lact 1999;15:241-246)

Products: To Help or Harm?
Changes in our economy have also brought about new product for the breastfeeding mother. We used to think how simple it was to breastfeed, because you didn’t have to BUY anything. Now there are "must-haves" and inevitable "gifts" that may even show up in ads in the obstetrician’s waiting room. Not only do we now have the "night-time bra", guaranteed to create a tropical, sugary environment on your breasts while you sleep; we also have ointments, creams, oils etc. to sooth sore nipples, acting further at a microscopic level to promote a hospitable nursery for germs. A recent life-threatening outbreak of systemic Candida infection (such as in the blood stream) in an intensive care nursery revealed the greatest risk factor to be the use of a lanolin/petrolatum ointment. Ironically, this product, which is similar to those advocated for mothers with sore nipples, was used to protect and lubricate the fragile, cracked skin of these premature babies. The report noted that occlusion of the skin changes the acid-base balance, the carbon dioxide emission rate, the bacterial flora, and enhances the growth of Candida. (Campbell JR, Zaccaria E, Baker CJ "Systemic Candidiasis in Extremely Low Birth Weight Infants Receiving Topical Petrolatum Ointment for Skin Care: A Case-Control Study" Pediatrics 2000; 105:1041-1045) The same would be true when these ointments and creams are used on sore nipples. But in this situation, the addition of sugar from the breastmilk would also promote growth and adherence of the yeast to host cells.

We must be concerned about the potential risks of these emollients, particularly when used on cracked nipples and in conjunction with other occlusive gear. Some mothers may have layers of topicals, breast shields, breast shells, pads and a variety of Velcro, hook, or snap garments which add to the barriers between breasts and air…not to mention the baby.

And what new mother isn’t given a pacifier, frequently a free "gift" from a pharmaceutical company. Not only has early use of pacifiers been associated with premature weaning, but they also frequently become heavily colonized with Candida albicans. Not that these new gadgets aren’t helpful in some way, but simply to remind us we are getting further away from the practice of breastfeeding, as known by our prehistoric sisters. And quite possibly we are creating problems in our efforts to solve others.

Pumps/Over-Production and the Risk of Mastitis
Finally, as many mothers admirably want to continue breastfeeding after returning to work, two other risk factors need to be appreciated. First, it becomes common to begin "stockpiling" efforts to have enough milk stored for the baby in the future. But by pumping and storing, the supply and demand ecosystem is unbalanced creating a situation known as "hyper lactation". The dairy industry is especially familiar with the risks of pump-dependent hyper lactation. This is why we hear so much about antibiotics in cows milk, a result of the efforts to control mastitis, which can be the cause of reduced milk production and profit. Whenever milk is not effectively drained, which is more a risk when a mother has one baby but produces enough milk for twins, she is likely to have pockets of milk stasis in the breast tissue and plugs in the nipple ducts. In addition, pumps may not empty a mother’s breasts as efficiently as her baby can, leaving areas in the periphery of the breast unemptied. It becomes imperative to assess the breasts after pumping to reduce this risk. Learning to massage the breasts and manually express after pumping can be a valuable technique.

Proceed With Caution - 4 -

What good advise would I offer a new mother?

• One of the greatest risks for infection is sore, cracked nipples. The best prevention is getting whatever help is needed to learn how to get a baby on the breast well….the sooner the better.
• Don’t fall for the "free gift packs" with pacifiers, coupons etc. given out by the hospital or, even worse the obstetrician’s office. This is not an altruistic effort, but a promotional tool.
• Keep your breasts as clean and dry as possible. Put a beach towel on the bed at night and don’t worry about leaking.
• Use topical ointments and creams only if absolutely needed and for as short a period as possible.
• Carefully and vigilantly inspect your breasts after pumping for areas of incompletely drained milk and work on those areas with heat, massage and further expression, either with the pump or by hand.
• Seek attention for early signs of infection, especially firm, painful lumps in the breasts, possibly with overlying inflamed skin. If more frequent emptying does not promptly solve the problem, oral medication may be needed.

We need to think carefully about the pros and cons of various practices and products, and at least anticipate the possible risks. I Hope these suggestions will be useful.


- Jane A. Morton M.D.