Medically reviewed on June 12, 2018
Mastitis is an infection of the breast tissue that results in breast pain, swelling, warmth and redness. You also might have fever and chills. Mastitis most commonly affects women who are breast-feeding (lactation mastitis), although sometimes this condition can occur in women who aren't breast-feeding.
In most cases, lactation mastitis occurs within the first six to 12 weeks after giving birth (postpartum), but it can happen later during breast-feeding. The condition can cause you to feel run down, making it difficult to care for your baby.
Sometimes mastitis leads a mother to wean her baby before she intends to, but continuing to breast-feed, even while taking an antibiotic for the mastitis, is better for you and your baby.
Mastitis, which mainly affects breast-feeding women, causes redness, swelling and pain in one breast.
With mastitis, signs and symptoms can appear suddenly and may include:
- Breast tenderness or warmth to the touch
- Generally feeling ill (malaise)
- Breast swelling
- Pain or a burning sensation continuously or while breast-feeding
- Skin redness, often in a wedge-shaped pattern
- Fever of 101 F (38.3 C) or greater
Although mastitis usually occurs in the first several weeks of breast-feeding, it can happen anytime during breast-feeding. Lactation mastitis tends to affect only one breast.
When to see a doctor
In most cases, you'll feel ill with flu-like symptoms for several hours before you recognize that your breast has an area of tenderness and redness. As soon as you recognize this combination of signs and symptoms, it's time to contact your doctor.
Your doctor will probably want to see you to confirm the diagnosis. Oral antibiotics are usually effective in treating this condition. If you've had mastitis before, your doctor may prescribe antibiotics over the phone. If your signs and symptoms don't improve after the first two days of taking antibiotics, see your doctor right away to make sure your condition isn't the result of a more serious problem.
Breast-feeding is a learned skill, and poor technique can lead to milk being trapped in the breast, a main cause of mastitis. Other causes include:
- A blocked milk duct. If a breast doesn't completely empty at feedings, one of your milk ducts can become clogged, causing milk to back up, which leads to breast infection.
- Bacteria entering your breast. Bacteria from your skin's surface and baby's mouth can enter the milk ducts through a break or crack in the skin of your nipple or through a milk duct opening. Stagnant milk in a breast that isn't emptied enough provides a breeding ground for the bacteria. The antibacterial properties of your milk help protect your baby from the infection.
Risk factors for mastitis include:
- Breast-feeding during the first few weeks after childbirth
- Sore or cracked nipples, although mastitis can develop without broken skin
- Using only one position to breast-feed, which may not fully drain your breast
- Wearing a tightfitting bra or putting pressure on your breast from using a seatbelt or carrying a heavy bag, which may restrict milk flow
- Becoming overly tired or stressed
- Previous bout of mastitis while breast-feeding
- Poor nutrition
If mastitis isn't adequately treated, or it's related to a blocked duct, a collection of pus (abscess) can develop in your breast and form a breast mass or area of firmness with thickening. An abscess usually requires surgical drainage. To avoid this complication, talk to your doctor as soon as you develop signs or symptoms of mastitis.
To get your breast-feeding relationship with your infant off to its best start — and to avoid complications like mastitis — consider meeting with a lactation consultant. A lactation consultant can give you tips and provide invaluable advice for proper breast-feeding techniques.
Minimize your chances of getting mastitis by following these tips:
- Fully drain the milk from your breasts while breast-feeding.
- Allow your baby to completely empty one breast before switching to the other breast during feeding.
- Change the position you use to breast-feed from one feeding to the next.
- Make sure your baby latches on properly during feedings.
Your doctor diagnoses mastitis based on a physical exam, taking into account signs and symptoms such as fever, chills and breast pain. Another clear sign is a wedge-shaped area of redness on the breast that points toward the nipple and is tender to the touch.
Your doctor will make sure you don't have a breast abscess — a complication that can occur when mastitis isn't treated promptly. A culture of your breast milk might help guide your doctor in determining the best antibiotic for you, especially if your infection is severe.
A rare form of breast cancer — inflammatory breast cancer — also can cause redness and swelling that could initially be confused with mastitis. Your doctor may recommend a diagnostic mammogram. If your signs and symptoms persist even after you complete a course of antibiotics, you may need a biopsy to make sure you don't have breast cancer.
Mastitis treatment usually involves:
- Antibiotics. Treating mastitis usually requires a 10- to 14-day course of antibiotics. You may feel well again 24 to 48 hours after starting antibiotics, but it's important to take all the pills to minimize your chance of recurrence.
- Pain relievers. Your doctor may recommend a mild pain reliever, such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others).
- Adjustments to your breast-feeding technique. Make sure that you fully empty your breasts during breast-feeding and that your infant latches on correctly. Your doctor may review your breast-feeding technique with you or may refer you to a lactation consultant for help and ongoing support.
- Self-care. Rest, continue breast-feeding and drink extra fluids to help your body fight the breast infection.
If your mastitis doesn't clear up after taking antibiotics, it is important to follow up with your doctor so he or she can decide if you need further testing.
Lifestyle and home remedies
If you have mastitis, it's safe to continue breast-feeding and it helps clear the infection.
To relieve your discomfort:
- Continue to breast-feed as often and as long as your baby is hungry
- Rest as much as possible, preferably in bed with your baby, which will encourage frequent feedings
- Avoid prolonged overfilling of your breast with milk (engorgement) before breast-feeding
- Vary your breast-feeding positions
- Drink plenty of fluids
- If you have trouble emptying a portion of your breast, apply warm compresses to the breast or take a warm shower before breast-feeding or pumping milk
- Wear a supportive bra
If breast-feeding on the infected breast is too painful or your infant refuses to nurse on that breast, try pumping or hand-expressing milk.
Preparing for an appointment
For mastitis, your first appointment will likely be with your regular obstetrician-gynecologist, family doctor or nurse practitioner. For problems related to breast-feeding, you may be referred to a lactation consultant.
What you can do
To prepare for your appointment:
- Note all your symptoms, even if they seem unrelated to the reason for which you scheduled the appointment.
- Review key personal information, including major stresses or recent life changes.
- List all medications, vitamins and supplements you take regularly.
- Write down questions to ask your doctor.
For mastitis, some basic questions to ask include:
- Will my infection clear on its own or do I need treatment?
- What can I do at home to relieve my symptoms?
- How might my condition affect my baby?
- Should I stop breast-feeding my baby?
- If I continue to breast-feed, is the medication you're prescribing safe for my baby?
- How long will I have to take the medication?
- What are the chances that the infection will recur? How do I minimize my risk of recurrence?
What to expect from your doctor
Your doctor may ask you questions about:
- How long you've had symptoms
- Whether you have breast pain and how severe it is
- Whether symptoms occur in one or both breasts
- Your breast-feeding technique
- Whether you've had previous breast infections