Causes
Mastitis is most frequently caused by milk stasis, where milk is not fully drained from the breast, causing it to back up into the milk ducts. This stagnant milk provides a breeding ground for bacteria. Infection often occurs when bacteria from the skin surface or the baby's mouth enter the milk ducts through a crack in the skin of the nipple or through a milk duct opening. The most common bacterium involved is Staphylococcus aureus. In non-breastfeeding individuals, causes may include infection of the milk ducts (periductal mastitis), often related to chronic inflammation or debris clogging the ducts.

Risk Factors
Several factors increase the likelihood of developing mastitis, particularly during lactation. These include sore or cracked nipples, which serve as an entry point for bacteria, and using only one position to breastfeed, which may not fully drain the breast. Wearing a tight-fitting bra or putting pressure on the breast from a seatbelt or heavy bag can restrict milk flow. Previous bouts of mastitis also increase the risk of recurrence. Furthermore, extreme fatigue and stress can lower the immune system's ability to fight off infection. For non-lactational mastitis, smoking is a significant risk factor as toxins in tobacco smoke can damage the ducts behind the nipple.

Prevention
Primary prevention focuses on effective breastfeeding management. Ensuring the baby latches on properly helps prevent nipple damage and ensures the breast empties efficiently. Changing breastfeeding positions can encourage milk removal from all areas of the breast. It is also beneficial to feed frequently and avoid letting the breasts become overly full. To reduce severity or recurrence, individuals should address cracked nipples immediately and ensure they finish breastfeeding on one side before switching to the other. For those prone to non-lactational mastitis, smoking cessation is a key preventive strategy.

Signs and Symptoms
The signs of mastitis often appear rapidly. The most recognizable symptom is a wedge-shaped area of the breast that becomes red, swollen, hard, and painful. This area feels warm or hot to the touch. Beyond localized breast symptoms, individuals typically experience systemic flu-like indicators, including a fever of 101°F (38.3°C) or higher, chills, fatigue, and general body aches. Some may also notice reactive swelling in the lymph nodes near the armpit. In lactating women, the milk supply may temporarily decrease in the affected breast.

Diagnosis
Clinicians typically identify mastitis through a physical examination and a review of symptoms. The visual presence of a red, tender wedge on the breast combined with fever is usually sufficient for diagnosis. If symptoms are severe, recurrent, or acquired in a hospital setting, a doctor may request a culture of the breast milk to identify the specific bacteria and determine the best antibiotic. If a collection of pus is suspected (an abscess), an ultrasound exam may be performed. It is important to differentiate mastitis from a plugged duct, which presents as a painful lump without fever or spreading redness. In rare cases where symptoms persist despite treatment, further testing may be done to rule out inflammatory breast cancer, which mimics the redness and swelling of mastitis.

Medical Treatment
The cornerstone of treating bacterial mastitis is a course of oral antibiotics, which are usually effective within 24 to 48 hours. Healthcare providers prescribe antibiotics that are safe for breastfeeding so the mother can continue to nurse. Over-the-counter pain relievers, such as ibuprofen or acetaminophen, are commonly used to reduce fever, inflammation, and pain. If an abscess has formed, it may require drainage through a minor procedure or needle aspiration performed by a specialist.

Lifestyle and Self-Care
Continued breastfeeding or pumping is critical for recovery, as emptying the breast helps clear the infection and prevents further milk stasis. It is safe for the baby to feed from the affected breast. Applying warm compresses before feeding can help milk flow, while cool compresses after feeding can soothe pain and reduce swelling. Rest and hydration are essential to help the body fight the infection. Gentle massage of the affected area toward the nipple during feeding can also assist in draining the ducts.

When to Seek Medical Care
Medical attention should be sought if you have symptoms of mastitis accompanied by a high fever, nausea, or vomiting that prevents you from taking fluids. If the redness spreads or red streaks appear extending toward the armpit, this requires immediate evaluation. Furthermore, if a tender lump remains after the redness and fever have resolved, or if symptoms do not improve after 24 hours of antibiotic treatment, follow-up is necessary to check for an abscess or resistant infection.

Severity and Course
Mastitis ranges from mild inflammation that resolves with improved drainage to severe infection requiring medical intervention. It is typically an acute condition, meaning it comes on suddenly and is of short duration. Most women begin to feel better within one to two days of starting antibiotics. While the condition is painful and draining, it is rarely life-threatening when treated promptly. However, if left untreated, the infection can progress to a breast abscess, which is a collection of pus that requires surgical drainage and can prolong recovery.

Prognosis and Long-Term Effects
The prognosis for mastitis is generally excellent. With appropriate treatment, symptoms usually resolve completely without permanent damage to breast tissue or function. Recurrence is possible, especially if the underlying cause, such as a poor latch, is not corrected. Severe or recurrent infections can occasionally lead to scarring or cessation of breastfeeding earlier than intended. Life expectancy is not affected by uncomplicated mastitis. In extremely rare cases, untreated infection can lead to sepsis, a systemic response to infection, but this is uncommon with access to modern healthcare.

Impact on Daily Activities
The physical pain and flu-like exhaustion associated with mastitis can make caring for a newborn challenging. Routine activities may be hindered by fatigue and the discomfort of clothing touching the sensitive breast. Mothers may feel discouraged or anxious about breastfeeding due to the pain, leading to emotional stress. It is often necessary to ask for help with household tasks and childcare to allow for adequate rest, which is vital for recovery.

Questions to Ask Your Healthcare Provider
Preparing questions can help you manage the condition effectively. Consider asking the following:

• Is this medication safe for my baby while I breastfeed?
• How often should I empty my breast to help clear the infection?
• What signs suggest that an abscess might be forming?
• If I cannot breastfeed due to pain, what is the best way to maintain my supply?
• Can you check my baby's latch to help prevent this from happening again?

Q: Can I continue to breastfeed if I have mastitis?
A: Yes, continuing to breastfeed is generally recommended and is considered part of the treatment. Frequent emptying of the breast helps clear the clogged ducts and infection. The milk remains safe for the baby even when you have an infection.

Q: Will mastitis go away on its own?
A: Mild cases caused only by a blocked duct might resolve with aggressive self-care like heat, massage, and frequent feeding within 12 to 24 hours. However, if symptoms persist or fever develops, prescription antibiotics are typically needed to clear the bacterial infection.

Q: Is mastitis contagious?
A: No, mastitis is not contagious. You cannot pass it to your baby or other family members. It is an inflammation or infection localized within your breast tissue.

Q: Does having mastitis increase my risk of breast cancer?
A: No, having mastitis does not increase the risk of developing breast cancer. However, because inflammatory breast cancer can mimic the symptoms of mastitis, any redness or swelling that does not go away with treatment should be evaluated by a doctor.

Q: Can men get mastitis?
A: Yes, although it is rare, men can develop mastitis. It is usually non-lactational and may be associated with smoking, nipple piercings, or other skin infections.