Breast redness has a wide range of causes, from a simple skin irritation to an infection that needs treatment. Most cases turn out to be something manageable, like mastitis or a rash in the skin fold beneath the breast. In rare cases, though, redness that doesn’t go away can signal something more serious. Understanding what each cause looks like will help you figure out what you’re dealing with.
Mastitis: The Most Common Culprit
If your breast is red, swollen, warm to the touch, and painful, mastitis is the most likely explanation, especially if you’re breastfeeding. Lactational mastitis happens when milk backs up in a duct and bacteria enter through a cracked or irritated nipple. The redness often appears as a wedge-shaped patch on one breast, and you may feel feverish, achy, and run down, almost like you have the flu.
Mastitis doesn’t only happen to breastfeeding women. Non-lactational mastitis causes similar redness and pain, sometimes along with a firm lump, and it can progress to skin breakdown, ulceration, or pus-draining tracts if left untreated. About 40% of women with non-lactational mastitis also develop nipple retraction, where the nipple pulls inward. Risk factors include smoking, nipple piercings, and conditions that cause duct blockage.
Both types of mastitis are treated with antibiotics, and symptoms typically start improving within 48 to 72 hours. If they don’t, your doctor will want to rule out an abscess or other causes.
Breast Abscess
An abscess forms when an infection pools into a pocket of pus inside the breast tissue. The redness is usually concentrated over a tender, swollen area that may feel fluctuant, almost like a water balloon under the skin. Fever, general malaise, and significant pain are common. On ultrasound, a fluid-filled collection confirms the diagnosis.
Small abscesses can sometimes be drained with a needle. Larger ones, particularly those 5 centimeters or more across, or collections that don’t resolve after repeated needle drainage, typically require surgical drainage.
Skin Fold Rash (Intertrigo)
Redness under the breast, right where skin meets skin, is often intertrigo. This is an irritation caused by moisture, friction, and warmth trapped in the fold. The skin looks red and raw, and it can sting or burn. It’s especially common in warm weather, after exercise, or in people with larger breasts.
When yeast (usually Candida) colonizes the irritated area, the redness intensifies and you may notice small satellite bumps or pustules surrounding the main rash. The skin can look wet or macerated, and peeling patches of dead skin come away easily. Bacterial intertrigo looks similar but often produces a noticeable bad odor. Both are treatable with topical antifungal or antibacterial creams, and keeping the area dry is key to preventing recurrence.
Eczema and Psoriasis
Eczema on the breast tends to appear as a poorly defined, patchy redness that may ooze fluid and itch intensely. It favors skin folds, so the underside of the breast and the area around the nipple are common spots. The skin may feel rough or look slightly swollen.
Psoriasis looks different. It forms thick, well-defined plaques with sharp borders. The patches feel rough or leathery and can crack and bleed. Psoriasis more commonly appears on elbows, knees, and the scalp, but it can show up on the breast too. If your redness has crisp edges and silvery scales, psoriasis is more likely than eczema.
Cellulitis
Cellulitis is a bacterial skin infection that causes a spreading area of redness, warmth, and tenderness. Unlike mastitis, it involves the skin itself rather than the breast tissue underneath. The redness often expands outward over hours to days and the skin may feel tight or swollen. Staphylococcus aureus is the most common bacterium responsible, though in women with diabetes, weakened immune systems, or other chronic conditions, less common bacteria can be involved. Oral antibiotics clear most cases, but rapidly spreading redness or high fever may need intravenous treatment.
Inflammatory Breast Cancer
This is the possibility most people are worried about when they search for breast redness, and it’s important to know about even though it’s rare. Inflammatory breast cancer (IBC) accounts for a small percentage of all breast cancers, but it’s aggressive and looks very different from a typical breast lump.
IBC causes rapid, diffuse redness across a large portion of the breast, often developing over days to weeks. The skin thickens and takes on a texture resembling orange peel, with tiny pits where the hair follicles are. This “peau d’orange” appearance is one of the hallmark signs. The breast may also swell noticeably, feel warm and heavy, and become tender. There is usually no distinct lump you can feel, which is part of why it can be mistaken for an infection.
The critical difference between IBC and mastitis is how the redness responds to antibiotics. Mastitis improves within a few days of starting treatment. If a course of antibiotics doesn’t reduce the redness, swelling, or skin changes, especially in an older or non-lactating woman, IBC needs to be ruled out with imaging and a skin biopsy. The American College of Radiology guidelines are clear: any breast inflammation that doesn’t respond to antibiotics should be evaluated for inflammatory breast cancer.
Paget’s Disease of the Nipple
If the redness is confined to your nipple and the darker skin surrounding it (the areola), Paget’s disease is a possibility worth knowing about. This rare form of breast cancer starts as a scaly, red, or crusty patch on the nipple that progresses slowly over months. Early on it looks almost identical to eczema, and many women are initially treated with steroid creams that provide no lasting improvement.
The key difference: eczema on the nipple tends to come and go and responds to topical treatment, while Paget’s disease is persistent and gradually worsens. The skin may fissure, ooze, or develop a well-defined plaque with a pink or red hue. Itching is often the first symptom. If nipple redness or scaling hasn’t resolved after a few weeks of treatment, a biopsy can provide a definitive answer.
Signs That Need Prompt Evaluation
Most breast redness is caused by infection or skin irritation, and most of those causes are straightforward to treat. But certain patterns deserve quick medical attention:
- Redness that spreads rapidly over hours, particularly with fever or chills, could indicate a worsening infection.
- Skin that looks like orange peel with pitting, thickening, or ridging.
- Redness that doesn’t improve after a full course of antibiotics.
- Nipple changes such as new retraction, persistent scaling, or bloody discharge.
- A new lump or swelling along with redness, particularly if the breast has changed in size or shape.
The CDC lists redness and flaky skin of the breast or nipple area among the warning signs of breast cancer. That doesn’t mean redness equals cancer. It means redness that persists without a clear explanation deserves imaging, and sometimes a biopsy, to make sure nothing is being missed.