Mastitis is inflammation of the breast tissue that can cause pain, swelling and sometimes flu-like symptoms if infection develops. It most commonly occurs in the early months of breastfeeding and often strikes suddenly. Recognizing what triggers mastitis and how long it usually lasts can help you get relief more quickly.

What Is Mastitis?

Mastitis is inflammation of the breast that can sometimes lead to infection. Mastitis can cause the breast to be red, swollen, and painful. The breast can also feel warm to the touch. If the breast is infected, a person may develop flu-like symptoms. Anyone can develop mastitis, but it is most common in women who are breastfeeding. It is most common in the first three months of breastfeeding.

Mastitis often occurs when a clogged milk duct does not let the milk fully drain from the breast, or when there is a break or crack in the skin of the nipple, which can lead to infection. When there is an infection, your white blood cells release a substance to fight the infection, which can lead to inflammation, increased blood flow, and swelling. Usually, mastitis is treated with antibiotics or emptying the milk from the breast.

How to Know if it’s Mastitis or a Clogged Milk Duct?

There are a few differences between mastitis and a clogged milk duct. Generally, a clogged milk duct develops over time and happens when a milk duct does not drain the milk properly. This can lead to an obstruction of the milk flow, which can cause a small nodule or swollen area of the breast. Mastitis, however, develops quickly and tends to cause more systemic issues. Mastitis is inflammation of the breast that is usually caused by an obstruction or infection in the breast.

Having a clogged milk duct can feel tender or uncomfortable, but usually only affects the area where the duct is clogged. With mastitis, a person can develop a fever and flu-like symptoms. There also tends to be more pain, swelling, redness, and heat in the affected breast.

How Common is Mastitis?

Mastitis is a common condition that affects around 10% of women in the US. It affects around 30% of pregnant women in the world. It is most common for women to develop mastitis in the first three months of pregnancy.

Signs and Symptoms of Mastitis

Symptoms of mastitis appear quickly. You can have symptoms in one or both breasts. The most common symptoms include:

• Breast pain
• Tenderness or discomfort
• Swelling
• Breast engorgement
• Redness that can appear as a wedge-like pattern
• Pain or burning sensation while breastfeeding
• The affected breast can feel warm to the touch
• Thickening of breast tissue or a lump or nodule
• Fever of 101 degrees Fahrenheit or higher
• Flu-like symptoms
• Muscle aches or pains

What Causes Mastitis?

Mastitis is triggered by factors that interfere with normal milk flow or allow bacteria into the breast. Common causes include:

• Hyperlactation. Overproduction of milk increases pressure inside the breast, compressing the ducts and preventing proper drainage. This stagnation can trigger inflammation and heighten the risk of infection if milk isn’t expressed regularly.
• Nipple trauma and infection. Cracks or soreness in the nipple skin can let bacteria from the skin surface or the infant’s mouth enter the milk ducts. Once inside, these germs can multiply and cause bacterial mastitis, which typically requires antibiotics for resolution.

Mastitis Risk Factors

The greatest risk factor for mastitis is breastfeeding, especially if you have an oversupply of milk. Other risk factors include:

• Having a history of mastitis
• Having cracked or sore nipples
• Not nursing appropriately
• Stress
• Being overly tired
• Poor nutrition or eating habits
• Smoking
• Putting pressure on the breast

Pressure includes wearing a tight bra or tight seatbelt, which can restrict milk flow.

Potential Complications

If bacterial mastitis is left untreated, it can develop into a breast abscess. An abscess typically requires surgery for the fluid to be drained.

How to Prevent Mastitis

It is recommended to meet with a lactation consultant before you start breastfeeding. Meeting with a consultant helps to reduce the risk of developing mastitis or complications from mastitis. Some common preventative measures may include:

• Feed or breastfeed on demand, or express the milk out with your hand.
• Drain one breast before switching to the next breast during feeding.
• Do not drain your breastmilk beyond your baby’s feeding needs or pump until fully empty, as this only perpetuates the cycle of hyperlactation and increases the risk of worsening the swelling and inflammation.
• Change the position you use for breastfeeding between feedings.
• Make sure your baby is appropriately latched on during feedings.
• Stop smoking or using tobacco products.

Diagnosis

Your healthcare provider will perform a physical exam and gather information about your symptoms and medical history before making a diagnosis. Typically, lab work is unnecessary to make a diagnosis, but sometimes further testing is recommended. If you developed mastitis while not breastfeeding, your doctor may recommend testing to rule out breast cancer. Tests may include:

• Breastmilk culture. This would be recommended if your mastitis is recurrent, severe, occurred in a hospital, or has not responded well to antibiotics.
• Ultrasound. If your mastitis has not gotten better with treatment within 48–72 hours, an ultrasound may be recommended.
• Mammogram. If your mastitis occurred while not breastfeeding and your doctor wants to rule out breast cancer, a mammogram may be recommended.
• Blood cultures. If the breast redness continues to expand or your vitals become unstable, a blood culture may be recommended.

Mastitis Treatment Options

The treatment for mastitis has changed over the years, making it important to consult with your doctor or lactation consultant if you suspect that you have mastitis. Treatment options focus on reducing the pain and inflammation from mastitis, as well as healing or preventing an infection from occurring. There are several different treatment options for mastitis, ranging from medications to home remedies. Typically, antibiotics are used for bacterial mastitis and at-home remedies are used for inflammatory mastitis.

At-Home Remedies and Treatments for Inflammatory Mastitis

There are several at-home remedies and treatments for inflammatory mastitis. Treatments include:

• Ice pack. Apply an ice pack or bag of frozen vegetables on the affected area while lying on your back. This helps the swelling drain into your lymph nodes. Never apply heat to the affected area.
• OTC pain medication. Over-the-counter NSAIDs (nonsteroidal anti-inflammatory drugs), such as naproxen or ibuprofen, can help to reduce swelling and pain associated with mastitis.
• Lymphatic drainage. This consists of light or gentle pressure being applied to the breast and movement toward the lymph nodes above your collar bone and in your armpit. Gently moving the fluid helps to reduce the swelling.
• Reverse pressure softening (RPS). This type of gentle massage helps to move fluid away from the areola and nipple and reduces swelling. It also allows your baby to latch on more easily. RPS is performed by placing two fingertips at the base of the nipple. Apply pressure and then drag the fingers away from the nipple. You can do this from several angles around the nipple.
• Wearing a supportive bra. It is important that you choose a bra that is supportive but not tight. You do not want to put more pressure on the breast by wearing a tight-fitting bra.

Things to Never Do to Treat Mastitis

Treatment for mastitis has changed over the years, so it is important to also know what not to do. Things you never want to do in treating mastitis include:

• Using heat on the affected area.
• Aggressively massaging your breast.
• Using any type of massage device on your breast.
• Soaking your breast.

Medications for Bacterial Mastitis

If inflammatory mastitis turns into bacterial mastitis, your doctor will prescribe an antibiotic to clear the infection. The infection should resolve in 10 days, but usually people start to feel better in 48–72 hours. You can still take over-the-counter pain relievers, such as acetaminophen or ibuprofen, to help manage the pain.

When Should You Contact Your Doctor?

If you suspect mastitis, it may be important to contact your doctor, especially since treatment options have changed over time. More specifically, if you notice any of the following issues, contact your doctor immediately:

• If at-home remedies to relieve engorgement are not working.
• Noticeable changes in the way your breasts feel.
• Nipple discharge of any amount.
• Newly discovered lump on your breasts.
• Worsening symptoms after 24 hours from taking an antibiotic.

Mastitis FAQs

How Long Does Mastitis Last?

With appropriate treatment, most people experience noticeable relief within 24–48 hours. Full resolution generally occurs within 7–10 days. However, factors such as early treatment, proper breastfeeding technique and underlying health conditions can influence how long symptoms persist.

Can Mastitis Resolve on Its Own?

If left untreated, mastitis can turn into bacterial mastitis, which means there is an infection. In some cases, bacterial mastitis can lead to an abscess, which requires surgery to drain.

Should You Keep Breastfeeding with Mastitis?

Yes. It is recommended to continue breastfeeding while treating mastitis. The breast infection cannot be passed to your baby while breastfeeding. In fact, breastfeeding may help to clear the infection because of the antibacterial properties within breast milk. It may feel painful or uncomfortable to continue breastfeeding, but it is important to do so.