Symptoms, risk factors and prevention of breast abscess caused by lactational mastitis

Mastitis is characterized by a tender area of localized erythema [Photo: Science Photo Library]

Mastitis is characterized by a tender area of localized erythema [Photo: Science Photo Library]

Lactational mastitis affects one in 5 breastfeeding women. It is most common in the first six weeks of breastfeeding, with the highest incidence occurring during the second and third week. As well as causing significant discomfort, it is a frequent reason for women to stop breastfeeding. It is initially localized to one segment of the breast, but untreated can spread to affect the whole breast.

Around 3% of lactating women with mastitis will develop a breast abscess, 1,10 although an incidence of up to 11% has been reported.

Lactational mastitis is usually bacterial in aetiology and can generally be effectively managed with oral antibiotics. Infections that do not improve rapidly require further investigation for breast abscess and nonlactational causes of inflammation, including the rare cause of inflammatory breast cancer.

In addition to antibiotics, management of lactational breast infections include symptomatic treatment, assessment of the infant’s attachment to the breast, and reassurance, emotional support, education and support for ongoing breastfeeding.

Physical examination
Breast pain is the primary symptom of mastitis. High fever is common, along with other generalized flu-like symptoms including malaise, lethargy, myalgia, sweating, headache, sometimes nausea and vomiting and occasionally rigors. Clinical examination of the breast should focus on looking for signs of inflammation (erythema, localized tenderness, heat, engorgement and swelling) and signs of nipple damage. General observations including temperature, pulse and blood pressure are important to exclude sepsis, which requires hospital admission.

Breast abscess is characterized by symptoms similar to mastitis, with the additional sign of a discrete tender lump, which may be tense or fluctuant. The mass may have overlying skin necrosis suggesting that the abscess is ‘pointing’ (abscess is sitting close to the surface of the skin). Less frequently, breast abscess presents as a non-tender lump without erythema (‘cold abscess’)

Risk factors and prevention
The main risk factor for mastitis is breastfeeding during the early postpartum period. Milk stasis and cracked nipples may contribute to the development of mastitis, although the evidence for this is inconclusive.

Other implicated factors include previous mastitis, maternal fatigue and primiparity. Reported risk factors for breast abscess include a past history of mastitis, maternal age over 30 years and gestational age greater than 41 weeks. There are no interventions that have been consistently proven to prevent mastitis. Encouraging emptying of milk from the breast is often recommended, however, evidence for its efficacy is inconclusive.

The most commonly practiced intervention is the prevention and management of damaged nipples. In some settings this may reduce the risk of developing mastitis. It is found that anti-secretory factor cereal, mupirocin ointment, fusidic acid ointment and breastfeeding advice had no significant impact on the initiation or duration of breastfeeding or the incidence of symptoms of mastitis.

Management of breast abscess and mastitis
The key components of management are symptom control, oral antibiotics and encouraging continued (milk flow from the affected breast. The patient should be reassured that antibiotics and simple analgesics will not harm her baby. Women should be encouraged to continue breastfeeding, to rest whenever possible and to drink plenty of fluids. Close monitoring is required to ensure that the infection resolves.

Simple analgesia
Regular oral paracetamol is first line treatment. Nonsteroidal anti-inflammatory drugs can be added. Both are safe in breastfeeding.

Hot and cold packs to breast
Evidence is inconsistent, however, breastfeeding authorities recommend:

• Gentle massage and warm compress prior to feeding (may encourage milk flow).
• Application of cold packs after feeding (may help alleviate pain). Cabbage leaves have demonstrated inconsistent effects; producing post-feeding symptom relief similar to ice packs in some studies, while demonstrating no effect in others.

Antibiotic therapy
Adequate antibiotic therapy is essential. Where possible this should be guided by microbiological culture and sensitivity (such as when fluid is aspirated from an abscess). As S. aureus is the common causative organism, antibiotic therapy of choice at least 5 days of flucloxacillin or dicloxacillin in a dose of 500 mg four times per day. For patients allergic to penicillin options include cephalexin or clindamycin.

Alternatives used overseas include amoxycillin/clavulanic acid and macrolides (erythromycin, clarithromycin). Avoid tetracycline, ciprofloxacin and chloramphenicol as they are unsafe for use in lactating women. Hospitalization for intravenous antibiotics is rarely required but is indicated if there are systemic signs of sepsis. Candida is a rare cause of mastitis and is characterized by the presence of intense pain, particularly noted after the breast empties, and the absence of breast erythema.

Continued breastfeeding
The aim of therapy is to continue breastfeeding and to empty the breast as fully as possible with each feed. This relieves symptoms and reduces the likelihood of progression to breast abscess. There is no evidence of risk of harm to a healthy infant feeding from an infected breast. If attachment is painful, a breast pump can be used to drain the breast until the infection settles enough to allow the baby to feed from the breast. Infant attachment to the breast should be checked and corrected. Referral to a lactation consultant may be helpful.

Despite support and encouragement, some women choose to cease breastfeeding. These women should be supported in their decision and encouraged to wean gradually, preferably after the infection has resolved. Sudden cessation of breastfeeding may exacerbate the infection, increasing the risk of abscess formation. Medication to suppress milk production is not recommended in this situation.

Drainage of breast abscess
Lactating women with a breast abscess often present late when the abscess is established and of large volume. The traditional management of breast abscess was surgical incision and drainage under general anaesthetic. This has been largely replaced by percutaneous (outpatient) aspiration under local anaesthetic where specialist breast clinics or radiology services are available. Surgery can usually be avoided and outcomes are better for outpatient clinic management than surgical management (including reduced pain and scarring and increased likelihood of continued breastfeeding).

Access to specialist breast clinics may be limited in some areas, particularly in rural areas, so surgical incision and drainage may be the treatment of choice in this setting.

Frequent review
Women with mastitis should be reviewed within 24–48 hours to ensure that the inflammation is settling. If minimal improvement occurs, breast ultrasound is indicated. Ultrasound helps detect any abscess and can guide aspiration. Ultrasound can identify or exclude other causes of inflammatory breast signs such as inflammatory breast cancer and can facilitate ultrasound guided biopsy if indicated by the imaging findings.

Source: Australian Family Physician, Vol. 40, 2011