What a Rash Under Your Breast May Mean

It’s normal to be concerned when you discover a red flush or pimple-like dots on your skin, but a rash under your breast could indicate any number of things. The good news: Most are mild or easy to treat.

Still, in rare cases, a breast rash can be a sign of something more serious. Here’s a roundup of likely causes, plus when to call a healthcare professional.

Infections 

Often, a below-the-breast rash is a sign of a mild infection. 

Mastitis 

Mastitis is breast pain, swelling, and itchiness or warmth, often on one side, due to a bacterial infection or irritation from clogged milk ducts. Typically, it’s the result of breastfeeding challenges but can also affect women and men who aren't nursing.

Along with a breast rash and fatigue, you may notice a wedge-shaped red area or nipple discharge that could contain pus. You may have flu-like symptoms like fever, chills, and nausea.

Usually, mastitis can be treated with oral antibiotics in about a week and a half. But it may take as long as three weeks to clear up. If it doesn’t, or it gets worse, contact a healthcare professional for a follow-up.

Cellulitis 

Cellulitis is a common, sometimes serious skin infection that occurs when a crack in your skin or an injury allows bacteria in. While it can be treated with antibiotics, the infection can escalate quickly and sometimes requires a hospital stay for additional care. 

If you have a fever and a rash that is red, swollen, tender, warm to the touch, or rapidly changing or growing, seek emergency medical care immediately. If you’ve got the rash but no fever, call a doctor to determine what to do next. Treatment is needed to prevent it from getting worse.

Shingles 

If you’ve had chickenpox, the varicella zoster virus that causes it remains in your body. Later in life, it can reappear as shingles in the form of a painful rash.

Symptoms include pain, itching, or tingling on your skin followed by a rash, sometimes many days later. Shingles often appears as a single red stripe on one side of your body and could also come with a fever, chills, headache, and upset stomach, per the Centers for Disease Control and Prevention.

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While shingles isn’t contagious, a person can catch chickenpox from someone who has shingles if they haven't had chickenpox previously. So keep your distance if you suspect you may have it. 

Your doctor can prescribe pain medication as well as antiviral medications, which can help shorten the attack. But they work best if you catch it within three days of the rash appearing, so don't delay.

Yeast Infection 

A yeast infection can also irritate the area below your breasts when yeast enters the body through a crack in skin or injured nipples while breastfeeding. 

Symptoms include a breast rash that might be painful, itchy, red, and shiny. You might have nipple irritation and—if you’re nursing—nipple pain that doesn’t end after you stop or change positions. 

Antifungal medications can ease pain and irritation. If you’re breastfeeding, talk to your doctor about treating both you and your baby to make sure the infection's gone for good.

Ringworm 

Despite the icky name, ringworm has nothing to do with worms. It's a scaly, ring-shaped rash caused by a fungal infection.

You can pick it up from other people, towels, or even pets. The rash may be itchy, slightly raised, or include overlapping or expanding rings or a clear or scaly area inside the ring.

Typically, an over-the-counter or prescription antifungal cream will do the trick within two weeks. If not, contact your doctor. You may need to take antifungal pills, too.

Skin Conditions 

If it’s not an infection causing your below-the-breast rash, another possibility is an underlying skin condition.

Heat Rash 

A heat rash can pop up when the sweat ducts beneath your breasts are blocked, trapping in perspiration. The result is clear, fluid-filled blisters and bumps; itchy, prickling red bumps; or goose bump–like areas on your skin. 

Blame the heat, humidity, and a too-tight shirt, chest strap, or bra. Usually, cooling off with a bath, cold compress, and looser clothing is the only fix you need. If that doesn’t work, contact a healthcare professional.

Scabies 

You might have scabies if the skin around and below your breasts and in other areas is so relentlessly itchy that it keeps you up at night. It’s caused by a tiny mite that burrows into your skin. Scabies frequently comes with a rash made of little bumps or hives that form a line.

To ease the itch, you and anyone in close contact with you will need a prescription cream, ointment, or lotion from a doctor to zap the mites. The rash or itch may get worse before it gets better but should fade within four weeks, per the American Academy of Dermatology (AAD).

Hailey-Hailey Disease 

Hailey-Hailey disease is a rare genetic condition that causes a blistering skin rash to pop up on the neck, armpits, skin folds (such as below the breast), and genitals. While these rashes fade and recur on their own, heat, sunlight, injury, or friction can make them worse. 

Avoiding these triggers can help, but sometimes cool compresses, prescription creams, and antibiotics are necessary for more serious cases.

Allergic Reactions 

Sometimes an allergic reaction can manifest as an itchy or swollen rash or flush of hives under the breast. 

Common culprits include: 

• Medication or supplements
• Foods such as nuts and fish
• Soap, shampoo, laundry detergent, or fragrances
• Airborne irritants like dust, pollen, or dander

Over-the-counter antihistamines like Benadryl (diphenhydramine) can often help calm hives, per the AAD. Contact your doctor if the rash is keeping you up at night, is sudden, painful, severe, or widespread, or doesn’t fade within three weeks.

If you experience signs of anaphylaxis (a severe allergic reaction) such as difficulty breathing, dizziness, or lightheadedness, seek emergency medical care immediately.

Autoimmune Conditions 

If you have an autoimmune condition, you may experience a below-the-breast rash because your immune system has shifted into overdrive. While there’s no cure for this, you can learn how to identify triggers and keep symptoms to a minimum.

Psoriasis 

Psoriasis is a chronic skin condition that sometimes causes skin lesions to develop under the breasts that appear smooth and bright red on lighter skin tones or purple, brown, or darker on skin of color. 

Flare-ups can be caused by certain medications, fungal infections, friction, stress, or tobacco or alcohol use, among other triggers.

After a diagnosis, your healthcare professional can help you learn how to manage this condition with topical creams, powders, and systemic medications.

Eczema 

A below-the-breast rash may fit the bill for eczema if your skin is itchy, inflamed, and discolored with rough, scaly patches. Symptoms of eczema can vary vastly, but they’re often triggered by stress or irritating soaps, fabrics, or fragrances.

You can learn how to manage flare-ups by knowing your triggers, adopting a regular skin care routine, and using over-the-counter and prescription medications you apply to your skin as well as immunosuppressant drugs.

Cancer 

While rare, breast inflammation that just won’t go away or is worsening rapidly could indicate a case of inflammatory breast cancer (IBC). Telltale symptoms include breast swelling, warmth, and irritation, purple or reddish skin, and thickening and dimpling of the breast surface that resembles an orange peel. 

It’s more common in Black women compared with White women and tends to occur in younger women under the age of 40. If treatment for mastitis doesn’t work within seven to 10 days, don’t hesitate to contact your doctor to rule out IBC, according to the American Cancer Society.

Summary

A rash under the breast could be caused by infection, skin conditions, allergic reactions, autoimmune conditions, and (rarely) cancer. The symptoms, causes, and treatments vary depending on the condition.

A rapidly spreading rash or breast growth, life-disrupting pain or itchiness, swollen lymph nodes, or signs of infection like pus are your cues to visit a healthcare professional as soon as possible.