A breast abscess is a painful collection of pus that forms in the breast.

Most abscesses develop just under the skin and are caused by a bacterial infection.

Breast abscesses are painful, swollen lumps that may also:

• be red
• feel hot
• cause the surrounding skin to swell
• cause a fever (high temperature)

What causes a breast abscess? 

Breast abscesses are often linked to mastitis – a condition that causes breast pain and swelling (inflammation), and usually affects women who are breastfeeding.

Infections can occur during breastfeeding if bacteria enter your breast tissue, or if the milk ducts (tiny tubes) become blocked. This can cause mastitis which, if not treated, can result in an abscess forming.

Women who aren't breastfeeding can also develop mastitis if bacteria enter the milk ducts through a sore or cracked nipple, or a nipple piercing.

White blood cells are sent to attack the infection, which causes tissue at the site of the infection to die. This creates a small, hollow area that fills with pus (an abscess).

Read more about what causes breast abscesses.

When to visit your GP

See your GP if your breast is red and sore. If you have mastitis, antibiotics may be prescribed to treat the infection.

If your symptoms persist after taking antibiotics, your GP may refer you for an ultrasound scan, which will confirm whether you have a breast abscess. This type of scan uses high-frequency sound waves to create an image of the inside of your body.

Treating a breast abscess

A breast abscess will need to be drained. Small breast abscesses can be drained using a needle and syringe. If the abscess is large, a small incision may be needed to drain the pus.

For both procedures, a local anaesthetic will usually be given to numb the skin around the abscess so you don't feel any pain or discomfort.

Read more about how breast abscesses are treated.