Last Updated on October 20, 2025 by Analgesia team
Definition of Mastitis in Medical
Mastitis is a medical term referring to inflammation of the breast tissue, often caused by a bacterial infection and most commonly occurring in breastfeeding women due to milk stasis (build-up of milk in the ducts), which can lead to painful swelling, redness, and warmth in the affected breast area; it may or may not be accompanied by a fever or other flu-like symptoms.
Mastitis symptom
Mastitis often develops suddenly and usually affects one breast, though in some cases both may be involved. The symptoms can appear within hours and range from mild discomfort to severe pain.
Here’s what to look out for:
1. Painful, swollen, hot breast
The affected breast may become tender, firm, and warm to the touch. The skin can look flushed or feel like chest pain on one side, usually worsening during breastfeeding or movement.
2. Red, painful, or hot lump
You might notice a hard, sore lump or an area of thickened tissue in the breast. This is often due to a blocked milk duct or local inflammation.
3. Wedge-shaped swelling
One of the classic signs of mastitis is a red, wedge-shaped patch on the breast — pointing outward from the nipple. This area may feel hot, swollen, and painful.
4. Red streaks on the breast
Visible red streaks radiating from the affected area toward the armpit or chest can signal spreading inflammation or infection.
5. Burning sensation
A burning or stinging pain may occur, especially during or after breastfeeding. This pain can linger even when the breast is not being touched.
6. Nipple discharge
Sometimes, mastitis causes nipple discharge, which may be white, yellowish, or streaked with blood. This can happen alongside cracking or soreness of the nipple.
7. Flu-like symptoms
Because mastitis often involves infection, you may feel generally unwell, with:
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Fever of 38°C (100.4°F) or higher
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Chills and shivering
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Body aches and fatigue
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Fast heart rate (tachycardia)
Important:
If your symptoms include a high fever, rapid heartbeat, or worsening redness or swelling, it’s important to see a doctor promptly. Untreated mastitis can lead to an abscess that may require drainage or antibiotics.
Common cause
Mastitis is a breast infection that can be caused by several factors, including milk build-up, infections, and injuries.
Milk build-up
- Milk stasis: A buildup of milk in the breast that can occur when a baby doesn’t latch on properly, or if feeds are infrequent or missed
- Oversupply: When milk builds up faster than it can be removed
- Blocked ducts: Milk ducts can become blocked if a breast doesn’t empty during feedings
Infections
- Germs from the skin or the baby’s mouth can enter the milk ducts through a crack in the nipple or a milk duct opening
- Staphylococcus aureus and Staphylococcus epidermidis: These are the predominant pathogens that cause mastitis
Injuries
- An injury that damages a milk duct or gland
Mastitis Treatment
Mastitis is usually treated with antibiotics and pain relievers. You should also rest, drain milk from your breast, and wear a supportive bra.
- A doctor will usually prescribe antibiotics if you have mastitis and your symptoms don’t improve
- Take all the antibiotics as prescribed, even if you feel better after a few doses
- A small amount of the antibiotic may pass into your breast milk, but it’s not harmful to your baby
- Take over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen
- Take paracetamol, which is safe to take while breastfeeding
Other treatments
- Empty milk from your breast
- Apply a cool pack to reduce swelling
- Perform lymphatic drainage by gently pressing your breast toward your lymph nodes
- Perform reverse pressure softening (RPS) to reduce swelling in your areola and nipple
- Wear a supportive bra
When to seek help
- If your symptoms don’t improve 12 to 24 hours after treating it at home
- If you have a breast abscess
- If you have breastfeeding problems
Who is most affected: Breastfeeding women, especially in the early postpartum period.