An abscess is the body’s way of dealing with an infection—by sealing it off to prevent the infection from spreading. Although rare in the breastfeeding mother, an abscess in the breast requires urgent diagnosis and treatment. This article looks at the symptoms, diagnosis and treatment pathways for a breast abscess.
What is a breast abscess?
A breast abscess will usually be felt as a very painful, swollen lump, inside the breast. It may be near the surface of the breast and have the characteristics of a boil or large spot or it may be much deeper inside the breast. Inside the lump there will be inflammation and an accumulation of pus—a thick liquid that contains dead tissue, cells and bacteria. The lump is caused by an infection, typically said to be by the bacteria Staphylococcus aureus1.
What are the symptoms of a breast abscess?
Aside from the physical presence of a painful lump, a mother may also have a temperature and flu-like symptoms. The skin on the breast above the lump may look very red or feel hot to touch. A doctor will give a firm diagnosis and prompt medical treatment is required if an abscess is confirmed. Not all breast lumps are abscesses as there are several other causes of lumpy breasts during breastfeeding—see Breast Lumps for further information.
Diagnosis of a breast abscess
A breast abscess can be diagnosed by ultrasound and a sample of the fluid in the middle of the lump can be removed with a fine needle for testing.
Causes and risk factors
A mother is most likely to develop a breast abscess if she has had a prolonged period of painful engorgement (when breasts are uncomfortably full of milk) and infective mastitis (breast inflammation) that wasn’t treated promptly or appropriately. Stopping breastfeeding abruptly during mastitis is also a risk factor for developing a breast abscess. However, occasionally a breast abscess can develop very quickly with little warning. Breastfeeding mothers are most at risk of an abscess during the first month after delivery (Kataria et al, 2013) and there is a higher risk of an abscess if a mother smokes or is obese.2
Avoiding a breast abscess
Removing as much milk as needed to keep the breasts feeling soft and comfortable by frequent breastfeeding, hand expressing or pumping is the best way to avoid a breast abscess. This is particularly important during a period of engorgement or mastitis. A lactating breast is never truly empty so in practice this means regularly removing or “draining” most of the available milk.
How to treat a breast abscess
An abscess needs immediate treatment. Abscesses are treated by draining away the collected pus in one of three ways: needle aspiration, catheter drainage or surgical incision and drainage. Antibiotics are usually prescribed. Which method to use can depend on the size of the breast abscess. Needle aspiration and antibiotics tend to be used for abscesses less than 3cm diameter and catheter drainage in abscesses larger than 3cm. Ultrasound guided aspiration in an outpatient clinic can be used for all sizes of abscess; although repeat drainage may still be necessary, it causes less scarring and avoids surgery.3
A very fine needle attached to a syringe is inserted into the centre of the abscess and the pus is drawn up in the syringe (needle aspiration). A sample can be sent away for culturing so the correct treatment can be identified. Needle aspiration may need repeating more than once over a period of a few days and antibiotics will be needed. Since repeated drainage can be stressful and cause a mother to stop breastfeeding, the Academy of Breastfeeding Medicine’s Protocol #36 recommends considering putting in a drain with the first needle aspiration procedure (see next section).4
A thin tube is inserted into the abscess through the skin to provide an outlet for the pus to drain away. Dr Jack Newman, a Canadian paediatrician and breastfeeding expert, recommends catheter drainage and antibiotic treatment rather than surgical incision and drainage. He states:
The radiologist maps out the abscess with ultrasound and inserts a catheter into the abscess to drain it. The catheter is kept in place until there is no further drainage and then removed. The mother continues breastfeeding on the affected side as she would have normally if she hadn’t developed the abscess. In general, we continue antibiotics based on the sensitivity of the bacterium until the mother is cured.
Wei et al describe a similar technique with good results using a drain tube and negative suction pressure to draw out the pus through a small incision.5
Surgical incision and drainage
A surgeon cuts into the abscess to release the pus and during the healing period a drainage system remains in place for any remaining pus to drain from the site. Antibiotics will also be prescribed. If surgical incision and drainage are needed, it is important to minimise the damage to glandular tissue. The incision should be as far away from the nipple as possible to make breastfeeding and pumping easier. And if the incision is made from the nipple towards the chest wall rather than across the ducts/around the breast there will be less damage to the milk ducts.6. Surgical drainage is no longer a preferred method of treatment 7
In addition to draining the infected material from the abscess, oral antibiotics effective against penicillin-resistant staphylococci are usually prescribed.8
Australian lactation consultant and doctor Pamela Douglas explains:
Antibiotics are required. First-line treatment is dicloxacillin or flucloxacillin 500 mg four times daily orally for 10–14 days. Methicillin-resistant S. aureus may require clindamycin 300 mg orally four times daily for 10–14 days. In the human body, undrained purulent fluid is usually not successfully treated by antibiotics alone. Drainage of symptomatic fluid collection is required to avoid fistula formation or septicemia.
Other places that recommend specific antibiotic treatments include a paper by Kataria et al 9 and the UK’s National Institute for Health and Care Excellence (NICE) antibiotic protocol at Mastitis and Breast Abscess, National Institute for Health and Care Excellence, 2021.
Can a breast abscess resolve without drainage?
As quoted above, Douglas states that both drainage and antibiotic treatment are usually required together to treat a breast abscess (Douglas, Vol 18: 1–20 2022). Kataria et al clarify that in the early stages of an abscess formation (cellulitic phase), antibiotics can resolve the skin infection but once an abscess has formed, removing the pus (aspiration) along with regular milk removal is recommended.
During the cellulitic phase, treatment with antibiotics may be expected to give rapid resolution. The predominance of S. aureus allows a rational choice of antibiotic without having to wait for the results of bacteriological culture. Erythromycin should be considered the drug of choice because it has high efficacy, is low cost, and has low risk of inducing bacterial resistance. Antibiotics should be continued for 10 days to reduce systemic infection and local cellulitis. Where an abscess has formed, aspiration of the pus, preferably under ultrasound control, has now supplanted open surgery as the first line of treatment. Regular natural milk emptying of the breast is an essential part of treatment.
How long does it take for a breast abscess to heal?
Wambach and Spencer10 write that abscesses greater than 3cm with catheter drainage will need the catheter in place for 3-7 days. For larger abscesses requiring an incision, they report that the incision heals from the inside out in a week or two. However Wilson-Clay and Hoover, the authors of The Breastfeeding Atlas, 2017, state that it is not unusual for the wound to take four to six weeks to heal after incision and drainage. They explain that the wound needs to heal slowly from the inside, if the process goes too quickly a fistula or milk fistula (persistent leaking hole) may form leading to more complications.
Milk leaking from the wound
It is common for breast milk to temporarily leak from the wound site during healing. Wilson-Clay and Hoover explain that this may be beneficial as breast milk contains various anti-inflammatory and immune factors that will help prevent infection. Covering the site with a dry, absorbent dressing—changing it as necessary—will usually be recommended by your health professional.
What is a fistula?
A fistula describes an area (a break in the skin or hole) on the breast that constantly leaks milk. A little initial leaking is common whenever a lactating breast has undergone medical intervention such as draining an abscess or taking a biopsy from the breast (taking a sample of cells for testing). Dr Jack Newman recommends continuing to breastfeed is the best way to avoid a fistula:
An important factor in preventing a fistula is to continue breastfeeding on that breast. If the mother doesn’t, the milk is likely to find the path of least resistance to flow, which may be this relatively large opening [the biopsy or abscess wound].
Should a fistula occur, it can dry up on its own without stopping breastfeeding on that side. If the mother does not want to stop breastfeeding on that side and can tolerate the leaking, there is no harm in leaving the fistula. If it is a problem, stopping breastfeeding on that breast only is an option.
Breasts work separately so, if breastfeeding is gradually stopped on one breast only, the other breast will usually compensate by increasing production. Medication to dry up a milk supply is not appropriate in this situation as it would affect both breasts. How to Stop Breastfeeding discusses reducing production in one or both breasts.
A persistent fistula may need further investigation to find the cause.
Can I carry on breastfeeding?
The National Health Service 11, NICE guidelines12 and The Academy of Breastfeeding Medicine 13 advise continuing to breastfeed during treatment of a breast abscess. It’s helpful to empty the breast as thoroughly as possible and avoid breast milk building up in the breast. As mentioned above, a lactating breast is never truly empty so in practice this means removing or draining most of the available milk. If it is too painful to breastfeed directly then try pumping or hand expressing. Some mothers continue to feed on the unaffected side while allowing the breast with the abscess to dry up.
Breastfeeding during treatment
Continue feeding with both breasts if you can. This will not harm your baby and can help your breast heal.
Try expressing milk from your breasts with your hand or a breast pump if breastfeeding is too painful.
What if MRSA is diagnosed?
Staphylococcus aureus is a bacteria found on our skin that is often associated with a breast abscess. When strains of Staphylococcus aureus bacteria (staph) are resistant to the usual antibiotics they are known as methicillin or meticillin-resistant Staphylococcus aureus (MRSA). In most cases by the time MRSA is diagnosed your baby will have already been exposed to the bacteria. Unless your baby is premature or very poorly, breastfeeding can usually continue uninterrupted while mother, or mother and baby, have treatment.14 MRSA can be spread by skin-to-skin contact so special hygiene precautions will be needed if you have an MRSA infected wound. For further information and recommendations if you have MRSA on the breast, especially if it is close to the nipple, see Staph, MRSA and Breastfeeding.
Not an abscess?
Occasionally breast cancer can present with similar symptoms to a breast abscess so it is important that a mother is under the care of her specialist physician. There are also other causes of breast lumps.
A breast abscess is a rare condition in a breastfeeding mother and usually follows a clear period of prolonged engorgement and infective mastitis. If you suspect you have an abscess the recommendations are to keep your breast milk flowing by frequent breastfeeding, hand expressing or pumping, and seek urgent treatment from your health care professionals.
*Excerpt reproduced by permission of Pinter and Martin.