Image credit: Flickr
Breast abscess (mastitis). Image credit: Flickr

Breast abscess is basically the inflamed, pus-filled, and hardened breast tissue felt as a lump. The abscess is due to bacteria (staphylococcus aureus) that cause the breast to turn inflamed and red, resulting in an infection called mastitis. If the infection is not treated in time, a breast abscess likely results.

The pus comprises a blend of white blood cells, bacteria, and dead tissue. With the infection progressing, more pus is made, making the abscess larger and more painful. Besides causing the area surrounding the pus to swell, the infection could also cause fever.


How does a breast infection involving bacteria happen? When the germs enter the body via the breast wound, they end up killing the cells in that particular region. The cells that die release cytokines, which are small proteins secreted by specific cells signifying response of the immune system.

Thereafter, an inflammatory response kick-starts, which increases blood flow and transports huge quantities of white blood cells (WBCs) to the affected region. The WBCs end up killing the affected tissue, leaving behind a vacuum that gets filled with pus. The healthy cells contribute to this immune system response by building a capsule or wall to gather the pus, resulting in the bulge.  

As aforementioned, staphylococcus aureus is the bacterium responsible for the condition. It isn’t a rare bacterium. It’s easily found on regular skin. The bacterium takes a dangerous avatar only when it manages to seek entry into the skin, which is through a crack or tear (in the case of breast abscess). The pathogen enters the body through a small break or crack in the nipple skin, which usually develops during breastfeeding.

The infection happens when the germ grows in size inside the milk ducts or the tubes that carry milk. And this overgrowth usually occurs when milk is not discharged properly and collects inside the milk duct. The infection attacks the breast’s fatty tissue and pressurizes the milk ducts and causes them to swell.


Usually, a breast abscess brings along pain, breast tenderness, and fever. However, there are also instances when inflammation is not that obvious. Breast engorgement, nipple tenderness and discharge, body fatigue and aches are also symptoms. 

Risk Factors

Breastfeeding Women

Breast abscess usually hurts breastfeeding women. The target age group is 18-50 years. However, the condition is rare among breastfeeding ladies. Only 1 to 3 percent of breastfeeding moms develop mastitis. Incomplete breastfeeding or engorgement (breast filled with milk) could add to the issue and worsen the symptoms. The abscess in breastfeeding women usually appears around and in the breast ducts. The bacteria (most often) originate from the baby’s mouth. Generally, breastfeeding women develop breast abscess within three months of feeding.

Several factors increase risk of breast abscess development. The risk factors associated with breastfeeding ladies are not sticking to a regular feeding schedule and skipping feeding sessions; wearing a too-tight bra that puts pressure on the milk ducts; exhaustion and stress; and weaning or quitting breastfeeding too early.

Non-Breastfeeding Women

Though rare, there are also instances when non-breastfeeding women develop mastitis, which is referred to as periductal mastitis. The bacteria, in this case, enters the ducts via a cracked or sore nipple, which may have been caused due to nipple piercing. Smoking and/or diabetes increase non-breastfeeding women’s vulnerability to the condition. At times, a badly done breast reduction surgery could also cause the abscess. In non-lactating ladies, the breast abscess is located below the nipple or close to the breast periphery (breast’s circumference or outer portion).

Breast abscess could likely develop in non-lactating ladies who are of child-bearing age, overweight, have had breast abscess in the past, smoke, and/or have inflammatory breast cancer (which is a fairly rare breast cancer type). Smoking indirectly or directly damages breast ducts’ walls, making them quite vulnerable to infections.

Mastitis is extremely rare in healthy women. However, ladies with a chronic illness, diabetes, AIDS, or a not-so-strong immune system could be susceptible. Breast abscess in postmenopausal and non-lactating women could be an indication of a rare form of breast cancer. Breast cancer risks go up when the inflamed portion doesn’t transform into pus, besides not responding to antibiotics. Women who’ve undergone breast cancer biopsies in the past could develop breast abscess in the subsequent days or weeks.


The diagnosis begins with the doctor physically feeling the lump. An ultrasound scan is the next step which helps confirm if breast abscess is indeed the issue. It also helps rule out more serious issues – for instance, breast cancer. The ultrasound helps determine the depth of the abscess and the different structures that could have been possibly affected. A magnetic resonance imaging (MRI) scan is done too, particularly if the infection is recurrent or severe.

Compared to an ultrasound, mammography results are not always conclusive. Typically, a breast abscess would show up on the mammogram as an irregularly shaped mass, with some regions of the mass being extremely distorted and of increased density. Breast cancer lesions could exhibit similar traits too.

An ultrasound is much more useful in ascertaining the condition with some authority; however, the quality of the actual image procured could vary based on the abscess’ location. For instance, when a breast abscess is situated right below the nipple and when there’s no palpable mass or swelling to base findings upon, ultrasound would show zero signs of an abscess. MRI scans are used in such scenarios for more clarity.


Usually, antibiotics are prescribed for mastitis treatment. If the abscess cannot be addressed through antibiotics, physical draining of the abscess would be the next ploy. Small breast abscesses could be treated with the help of a syringe and needle. Ultrasound could be used to ensure the needle hits the right spot. A large abscess would require a minor surgical cut or incision for draining. With both the needle and incision treatment, local anesthesia is usually administered to numb the area surrounding the abscess so that there’s no pain or discomfort during the medical procedure.

Surgery is the last resort. The surgical procedure entails removing the recurring abscess and also the affected glands, if any. In case the abscess has induced nipple inversion, reconstruction would be done during the surgery. Based on the abscess’ severity and size, the surgery could be performed in a hospital, outpatient center, or doctor’s office. Many such breast surgeries are performed near the areola (the dark area encircling the nipple) for aesthetic reasons. However, this could result in more milk ducts being cut and milk supply being affected.

Post-Surgery (Healing and Care)

After surgery, the incision is not sutured. It’s left open to be stuffed with dressing (sterile gauze sponge or pad) so that the area can drain and heal by itself with time. A one night hospital stay is mandatory. At times, the stay could be extended to as many as five days, depending on the abscess’ severity. The dressing needs to be changed at least once a day for the next two to three weeks or until the incision completely heals. The hospital could appoint a nurse to perform the dressing at home or a member of the patient’s family could be instructed or trained on the same. There should be no breast pain after surgery. The incision area may hurt, however, until it completely heals. 

Breastfeeding After Surgery

A mother must continue breastfeeding from the affected breast after surgery, unless the abscess site is not too close to the nipple or areola. In case the abscess location impedes direct breastfeeding, it’s recommended to express or squeeze out milk from the particular breast till the incision heals.

Breast milk shouldn’t interfere with the healing process. It’s a misconception that the milk, if it comes in contact with the incision, would delay healing. Breast milk comprises immune factors that could ensure there’s no further infection. The milk dripping out of the nipple may be messy, but it should not be a real cause for concern. Therefore, if breastfeeding is not an option, manually squeezing out the milk should become a mandatory resort until the incision heals and breastfeeding could be resumed. In fact, if the breast is not drained regularly, it could get full and likely cause mastitis or block the ducts again.