What Is a Breast Cancer Rash? A Doctor Explains

A breast lump is the most common and recognized symptom of breast cancer, according to a 2023 study published in Preventive Medicine Reports. Yet the research points out that awareness of other breast cancer symptoms, such as a breast cancer rash, remains low. This worries experts because cancerous breast lumps aren’t always easily detectable by touch—and some types of breast cancer may not form a lump at all.

That’s generally the case for inflammatory breast cancer (IBC), explains Anubha Bharthuar, MD, a Medical Oncologist and Hematologist at Tufts Medical Center and Tufts Medicine Cancer Center – Stoneham. “Oftentimes, no mass is able to be felt,” she says. “This is different from the other types of breast cancer that usually present as a non-tender, palpable lump or mass in the breast or armpit.” Instead, a breast cancer rash is the most common sign of IBC.  

Inflammatory breast cancer is relatively rare, accounting for about 1-5% of all breast cancers, according to the American Cancer Society. But it’s aggressive and fast-growing, requiring immediate treatment, says Azka Ali, MD, a Medical Oncologist at Cleveland Clinic Cancer Institute. “Patients can have a sudden appearance of clinical signs and symptoms, sometimes even as rapid as the emergence of symptoms within a six-month period.” 

What does an inflammatory breast cancer rash look like?

A breast cancer rash causes changes to the breast’s skin color and texture. Dr. Bharthuar says that: 

• The affected breast will have an area that looks red or purple, like a bruise. 
• The breast skin can appear thickened or swollen.
• The breast texture feels firm or leathery.

Dr. Ali adds that a rash or swelling that takes up more than one-third of the breast surface is considered a high-risk feature. “A more serious presentation is called ‘peau d’ orange,’ termed for the texture and appearance of an orange peel,” she says. 

These symptoms can appear suddenly and progress quickly. Sometimes, they develop over several months, while in other cases, a breast cancer rash can form within a few weeks, according to the Cleveland Clinic. 

What is inflammatory breast cancer?

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“Inflammatory breast cancer is an uncommon type of aggressive, locally advanced breast cancer where the breast looks enlarged, red, inflamed and can be painful,” Dr. Bharthuar says. She explains that there can be quite a bit of variability in IBC’s presentation from one patient to the next. 

Still, 2022 research published in Breast Cancer Research & Treatment says that abnormal redness, rash, and swelling over at least one-third of the breast is the most common diagnostic sign. The research also says that a hallmark feature of inflammatory breast cancer is the sudden, rapid onset of symptoms. More common forms of breast cancer tend to grow more slowly, such as invasive ductal carcinoma, which accounts for 70-80% of all breast cancer cases.

Historically, inflammatory breast cancer has had a five-year survival rate of around 40%, according to the MD Anderson Cancer Center (MDACC) at the University of Texas. However, recent advances in breast cancer treatments have increased this survival rate to up to 70%, depending on factors such as the stage of the disease at diagnosis and a patient’s overall health status. 

Why does inflammatory breast cancer cause a rash?

Most types of breast cancers form a lump as the cancerous cells multiply in breast tissue. But with inflammatory breast cancer, the cancer cells are present in the skin of the affected breast, Dr. Bharthuar says. These cells block the skin’s lymph vessels—small drainage tubes—and disrupt normal circulation, leading to a rash and other possible symptoms. 

“The redness and swelling can vary in intensity from patient to patient,” says Dr. Ali. For some women, this breast cancer rash may even come and go, according to the National Breast Cancer Foundation. But the rash and other IBC symptoms will worsen and become more persistent as the cancer progresses. 

Symptoms of inflammatory breast cancer

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The extent of breast skin change and rapidity of symptom development are the key features of inflammatory breast cancer, says Dr. Ali. “Skin discoloration can range from pink, red…to bruised, purple skin,” she says. Breast texture can feel swollen and firm or leathery, Dr. Bharthuar adds. “The skin can have a pitted appearance similar to that of an orange peel.” 

But both experts say that other symptoms may present, such as:

• The breast may be warm and painful to touch.
• The breast may appear larger and feel heavier than the unaffected side. 
• There may be nipple abnormalities: crusting of the nipple, new nipple flattening, or new nipple inversions. 
• A palpable lump in the armpit or underarm area could occur (signaling lymph node changes).

What’s notable about IBC is that these symptoms can come on extremely fast. What may start as a small pink rash can rapidly evolve—even overnight—with symptoms worsening quickly. 

How inflammatory breast cancer is diagnosed

“If your doctor suspects inflammatory breast cancer, you will undergo imaging investigations such as a mammogram, breast ultrasound, or MRI,” Dr. Bharthuar says. “You will then have a breast biopsy, which is the definitive test to confirm cancer.”

Dr. Ali adds that patients will often need extensive evaluation of the axilla—the area below your shoulder joint where lymph nodes are present—as well as the rest of the body. “[This is to] accurately assess the spread of cancer within the body, determining the clinical stage of the cancer.” 

According to the Cleveland Clinic, by the time IBC symptoms appear, it’s usually already at stage III—the cancer is in breast tissue skin—or stage IV—the cancer has spread from your breast to other organs. 

Who’s at risk for inflammatory breast cancer?

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Research published in in StatPearls in 2023 says that a high body mass index is an independent risk factor for inflammatory breast cancer. “Women younger than 40, those who are overweight, and women of African-American ancestry are often at a higher risk for inflammatory breast cancer,” Dr. Bharthuar explains. 

The NIH research adds that other possible—but unconfirmed—risk factors currently being studied include:

• Viral infections and chronic inflammation
• Premature birth
• Smoking
• Breastfeeding 

Research is mixed on whether genetics or a family history of IBC increase your risk. At this time, no inherited genetic mutations have been conclusively linked to IBC.

However, family history is a strong risk factor for other forms of breast cancer. Having a first-degree relative who had breast cancer (a mother or sister, for instance) almost doubles your risk, according to the American Cancer Society. So, experts advise women with this risk factor to get regular screenings for breast cancers—and if you develop a breast rash, have it checked by your doctor ASAP.

Other causes of a breast rash

Bacterial or viral skin infections can also cause a breast rash, says Dr. Ali. “These can be skin or soft tissue infections or inflammatory reactions of the skin called cellulitis.” She says that one example of a viral skin infection that affects the breast is due to shingles, [a virus] that lays dormant in the body and can reactivate at various points over time. 

“Another common cause of breast rash is mastitis, which is infection or inflammation of breast tissue resulting in pain, swelling, warmth, and redness,” Dr. Ali says. “This is commonly seen in younger, breastfeeding women.” 

Unfortunately, due to similarities in appearance and symptoms like breast pain and tenderness, a breast cancer rash can be mistaken for inflammation or infection, Dr. Bharthuar says. 

When to see a doctor for a breast rash

“A rash on the breast must always be rapidly evaluated to properly investigate next steps,” Dr. Ali says. This is because of how similar breast rashes appear, whether caused by an easily-treatable infection or this aggressive cancer. 

The main difference doctors look out for is the progression of the rash, particularly in response to treatment. A healthcare provider may prescribe antibiotics, which generally resolve an infection-based rash within a week. But if the rash worsens with antibiotic treatment and/or new symptoms emerge, your doctor may suspect IBC and proceed with further diagnostic testing. 

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• 9 Ways Your Breasts Can Change as You Age