Mastitis - Breast Infection

Overview, Causes, & Risk Factors

A breast infection involves an infection of the breast tissue and/or the milk ducts of the breast.

What is going on in the body?

Breast infections are most common in women who are breast-feeding. Bacteria can get into the milk ducts through a crack in the nipple and cause an infection. Incomplete emptying of breast milk during feedings can contribute to the problem. Milk ducts can become blocked. A breast infection can also occur when bacteria enter the tissue through an opening on the skin.

What are the causes and risks of the infection?

Breast infections are caused when bacteria enter the milk-producing ducts or an open area on the breast. They are more likely when the flow of milk is blocked or restricted. Factors that increase a woman's risk for breast infection include the following:

blocked milk duct

breast abnormalities, such as those following breast surgery

cigarette smoking

conditions that lower resistance to infection, including anemia, stress, and diabetes

exercising the upper arm too much, such as shoveling snow

fibrocystic changes in the breast

going too long between breast-feeding sessions

incorrect positioning of the baby during breast-feeding

irregular breast-feeding

nipple shields

objects that press on the breast, such as heavy shoulder bags

past injuries to the breast

skipping feedings

stopping breast-feeding suddenly

teething pain in the infant

tight clothing, such as underwire bras

Symptoms & Signs

What are the signs and symptoms of the infection?

Symptoms of a breast infection include the following:

discharge from the nipple

feeling of warmth in the breast

fever

flu-like symptoms

pain and/or discomfort in the breast

a red and swollen area of the breast

Diagnosis & Tests

How is the infection diagnosed?

Diagnosis of a breast infection begins with a medical history and physical exam. A culture may be done of the breast milk or the skin surface to check for bacteria. The healthcare provider may order a mammogram or breast biopsy if the cause is not evident.

Prevention & Expectations

What can be done to prevent the infection?

A woman can lower her risk for a breast infection by:

avoiding excessive exercise of the upper arms

avoiding restrictive clothing or objects over the breast

breast-feeding equally from both breasts

drinking adequate fluids

ensuring that the baby is suckling properly

expressing breast milk when she is away from the baby during regular feeding times

following a regular schedule for breast-feeding

positioning the baby correctly

seeking effective treatment for conditions such as anemia

washing hands prior to breast-feeding

What are the long-term effects of the infection?

Long-term effects depend upon the underlying cause. For breast-feeding women with mastitis, the condition usually clears quickly with antibiotic medicine. All of the prescribed antibiotic should be taken as directed to keep the infection from returning later.

A severe breast infection can lead to the development of a breast abscess, or collection of pus. A breast abscess might need to be drained surgically. In this instance, the woman might be advised to discontinue breast-feeding.

Treatment & Monitoring

What are the treatments for the infection?

If possible, breast-feeding or using a breast pump to express milk should be continued. It may also help to gently massage the breast. This keeps the milk ducts of the breast open. Wearing a well-fitted nursing bra will help reduce excessive swelling. A healthcare provider may prescribe an antibiotic until the infection is under control. Application of warm compresses may also help. Symptoms usually subside in 2 to 3 days after treatment.

What are the side effects of the treatments?

If breast-feeding is continued, the healthcare provider should make sure that any medicines used are safe for the baby. Antibiotics can cause allergic reactions and stomach upset.

What happens after treatment for the infection?

Any new or worsening symptoms should be reported to the healthcare provider.

How is the infection monitored?

A follow-up appointment with a healthcare provider is important to make sure the condition is improving.