What Is Mastitis?

Mastitis is inflammation of breast tissue that causes pain, redness, and swelling. It typically occurs in people who breastfeed (lactational), but it can occur in other people as well (non-lactational). 

Worldwide, mastitis affects up to 30% of people who breastfeed. It affects 7-10% of breastfeeding people in the United States. It most commonly occurs in the first three weeks after delivery.

Mastitis is usually caused by a bacterial breast infection or excessive swelling of the milk ducts (tubes that carry milk from glands to the nipple). It can make breastfeeding uncomfortable and sometimes painful. However, it is very treatable. With prompt treatment, most people recover without complications and can continue breastfeeding. 

Types of Mastitis

Mastitis falls into two basic categories: lactational mastitis and non-lactational mastitis. Healthcare providers may also categorize mastitis by severity, clinical presentation, and complications. 

Lactational Mastitis 

Lactational mastitis (puerperal mastitis) is the most common type of mastitis. It occurs in people who breastfeed. It is caused by prolonged swelling (engorgement) and bacterial infection rather than a one-time delay in feeding. 

Non-Lactational Mastitis 

Non-lactational mastitis affects people who are not breastfeeding. It typically occurs due to blockage in the milk ducts, injury to the breast, or breast tissue infection. 

Types of non-lactational mastitis include: 

• Periductal mastitis: A benign condition that usually occurs in reproductive-aged women.
• Idiopathic granulomatous mastitis (IGM): A very rare type of non-lactational mastitis that develops within five years of giving birth. It most commonly occurs six months to two years after stopping breastfeeding and can mimic breast cancer.

Other Types of Mastitis

Mastitis can also be characterized by the presence or absence of complications, as well as by its recurrence.

• Uncomplicated mastitis: The most common category of mastitis, which involves mild to moderate symptoms. Treatment generally works quickly and efficiently.
• Complicated mastitis: Mastitis can be complicated by an abscess (collection of pus in the breast tissue), more severe symptoms, or an antibiotic-resistant infection. In this case, the mastitis requires more aggressive treatment.
• Recurrent mastitis: Multiple episodes of mastitis.

Mastitis Symptoms 

Symptoms of mastitis can vary. Common signs and symptoms include:

• Nipple pain 
• Breast pain (typically in one spot)
• Breast swelling, fullness, or heaviness
• Nipple changes 
• Redness and warmth
• Itchiness over the breast tissue
• Armpit tenderness
• Firmness, thickening, or lumps in the breast where the ducts are blocked or inflamed
• Nipple discharge, which might be pus-like or contain blood
• Flu-like symptoms, such as fever, chills, fatigue, or body aches

Causes

Lactional mastitis is caused by bacteria and ineffective milk drainage. Non-lactational mastitis causes remain unclear but might be related to a variety of factors.

Lactational Mastitis

Infection

An infection can develop when bacteria enter the breast tissue through a cracked or sore nipple. This triggers an immune response in the breast tissue and causes inflammation, redness, and discomfort. The infection can spread beyond breast tissue into the rest of the body, causing flu-like symptoms. 

Bacterial causes of mastitis are usually due to Staphylococcus aureus (staph). However, methicillin-resistant S. aureus (MRSA)—a staph strain that is resistant to the antibiotic methicillin—is becoming a more common cause.

Sore or cracked nipples can provide an entry point for bacteria on the breastfeeding person's skin or from the baby’s mouth.

Milk duct blockage

Mastitis can occur due to blockage in the milk ducts. The blockage causes milk stasis, meaning the milk accumulates or backs up because it cannot flow freely. 

Milk stasis itself does not cause an infection, but the blockage can lead to swelling and stretching of breast tissue. Stagnant milk is also an ideal environment for bacteria to grow.

Non-Lactational Mastitis

Causes of non-lactational mastitis are unclear but might include immune responses.

For example, IGM might be related to:

• Autoimmunity (when the body mistakenly attacks its own healthy cells)
• Infection
  
• An imbalance of the sex hormones estrogen and progesterone
• Abnormally high prolactin levels (a hormone that stimulates breast milk production)
• Smoking

Risk Factors 

Risk factors for mastitis include:

• Breastfeeding, especially in the first few weeks and months
• Cracked or sore nipples
• Feeding techniques, such as improper latching, less frequent feeding, or always feeding in the same position
• Inadequate milk removal or an overabundance of milk
• Fewer feedings due to separation from the infant (for example, going back to work), illness, or the infant sleeping longer at night
• Restrictive clothing or bras, which put pressure on the breast
• A weakened immune system, excess stress, or lack of sleep
  
• Smoking cigarettes, which might damage milk ducts
• Prior history of mastitis

Diagnosis

Mastitis is typically diagnosed based on a medical history and clinical exam. The healthcare provider may ask you about breastfeeding practices, nipple trauma, mastitis history, general overall health, and flu-like symptoms. They will examine your breast for swelling, redness, and tenderness.

Complicated mastitis may require tests such as:

• Breast ultrasound: A technology that uses sound waves to generate breast images (sonograms)
• Culture: A sample of nipple discharge to identify the type of bacteria present
• Blood tests: To check for signs of infection
• Biopsy: A procedure that removes a sample of cells or tissue so it can be examined under a microscope and tested. A biopsy is required to diagnose IGM because the features can mimic breast cancer.

Mastitis Treatment

Treatment for mastitis might include a combination of self-care measures and medical treatment options.

Home Remedies

Home remedies for mastitis can often relieve symptoms, especially if symptoms are relatively mild. Home remedies include:

• Empty breast milk frequently through pumping or breastfeeding, starting with the affected breast
• Ensure your breast is empty after feeding by pumping or hand-expressing (using your hands to massage out milk) as needed
• Massage the painful area, moving toward the nipple, to help drain your breast after feeding
• Try lymphatic massage, which involves massaging the skin from your areola to your armpits to promote fluid drainage from glands under your arm
• Change breastfeeding positions
• Prioritize rest
• Drink plenty of fluids
• Use a cool compress after emptying milk to reduce pain and swelling
• Ask your healthcare provider about trying over-the-counter (OTC) pain relief medications such as Tylenol (acetaminophen) or Advil (ibuprofen) 

Medical Treatment

Medical treatment might be necessary if symptoms persist or are more severe, or if there's a complication like an abscess. This might include:

• Antibiotics, if symptoms last longer than 12-24 hours
• Corticosteroids (anti-inflammatory medications)
• Immunosuppressants (medications that reduce the body's immune response)
  
• Surgical drainage, if there is an abscess
• Surgical removal of ducts
  

Always consult with your healthcare provider before taking medications, including OTC pain medications, especially when breastfeeding.

Prevention

Mastitis prevention involves a combination of the following strategies:

• Ensure proper latching to prevent nipple damage and promote effective milk removal
• Empty your breast regularly through pumping or breastfeeding, as infrequent emptying can lead to milk stasis
• Avoid sudden weaning to decrease the risk of engorgement and milk stasis
• Change your breastfeeding position from one feeding to the next
• Ensure thorough milk removal during each feeding session, and consider pumping afterward if the baby doesn't empty the breast
• Maintain breast hygiene by keeping your nipples clean and dry
• Avoid harsh soaps or lotions that may cause nipple cracking
• Treat sore or cracked nipples by using lanolin or applying breast milk 
• Wear loose-fitting, comfortable clothing and bras, as tight clothing can restrict milk flow

Consider seeking guidance from a lactation consultant if you have concerns about breastfeeding techniques. Lactation consultants are certified health professionals that specialize in breastfeeding.

Complications 

Untreated mastitis can lead to various complications, including:

• Breastfeeding difficulties: Mastitis can cause pain, inflammation, and swelling, affecting milk supply and the overall breastfeeding experience. The most common complication is ending breastfeeding early.
• Breast abscess: An abscess is a collection of pus in the breast tissue that may require a minor surgical procedure to drain. It's more common with delayed treatment.
• Milk blister (bleb): A milk blister is a white, painful dot on the nipple or areola. It might resolve on its own within a few weeks, but you can also treat it as you would mastitis. Avoid soap on the area, and do not open the blister yourself, as this can lead to infection.
• Recurrent or chronic mastitis: Recurrent or persistent inflammation, infection, or discomfort can lead to breast changes, scarring, and breastfeeding challenges. 
• Challenging emotions: Coping with mastitis can be frustrating and draining. Some people may feel guilty about breastfeeding difficulties or their ability to care for the baby.

A Quick Review

Most people fully recover from mastitis without long-term complications, especially if they seek treatment early, follow the treatment plan, and take the full course of antibiotics. Self-care measures and antibiotics typically improve mastitis within a few days to a week. 

Remedies include drinking plenty of fluids, resting, using cool compresses, and taking pain medication as recommended by your healthcare provider. Breastfeeding or expressing milk regularly can help clear the infection and maintain milk production. Don’t hesitate to ask for support from family and friends, healthcare professionals, and lactation consultants.