Breast changes are to be expected while you’re breastfeeding. Your breasts may become larger or more tender, or they may develop visible bumps. If you discover uncommon or worrying breast symptoms, you might wonder if they indicate breast cancer.

Some concerning breast changes can indicate mastitis, a noncancerous breast condition that most often affects those who are breastfeeding. While breast cancer is rare while breastfeeding, mastitis is more common.

Mastitis and breast cancer have similar signs and symptoms that might raise concern if you’re not sure of the difference. If left untreated, mastitis can become a serious breast infection, so it’s important to recognize it early. Read on for key similarities and differences between mastitis and breast cancer.

Similarities Between Mastitis and Breast Cancer

Mastitis and breast cancer can cause similar changes to the affected breast, so it’s easy to mistake mastitis for breast cancer without further investigation. Inflammatory breast cancer (IBC) may be misdiagnosed as mastitis because it can appear to be similar.

Here are a few similarities between mastitis and breast cancer that you should know.

A lump in the breast is perhaps the most widely recognized sign of many breast cancer types. While a lump doesn’t always indicate breast cancer, it’s always worth investigating. Breast cancer lumps commonly develop in the breast tissue or the armpit.

Mastitis also commonly causes a lump to develop in the affected breast. A mastitis lump is typically hard. These lumps tend to be small and painful, forming due to an initially blocked milk duct.

Breast cancer and mastitis aren’t the only conditions that can cause a lump in your breast while you’re breastfeeding. A lump can also be a sign of a cyst, a galactocele (milk-filled cyst), or fibroadenoma. Always tell your doctor if you feel a lump in your breast or armpit, even if it’s not painful.

IBC is a rare type of breast cancer that accounts for 1 percent to 5 percent of all breast cancer cases. It often doesn’t cause a breast lump. Instead, its main symptoms include:

• Breast swelling
• Skin discoloration
• Warmth
• Tenderness or pain

These symptoms can all suggest inflammation of the breast. Mastitis breast inflammation also causes swelling, tenderness, redness, and warmth in the affected breast.

Mastitis is much more common than inflammatory breast cancer, especially when breastfeeding. That’s why healthcare providers might assume it’s mastitis and prescribe antibiotics first.

The similarities between IBC and mastitis don’t stop with inflammation. Both conditions can also thicken the skin of your breast. When skin thickening occurs in IBC, the skin also tends to take on a pitted appearance similar to an orange peel.

Lymph nodes are small, bean-shaped organs that are part of the immune system. They help filter lymph fluid and store white blood cells that help fight infection. Lymph nodes are found throughout the body, including under the arms, under the collarbone, in the neck, and in the groin.

When mastitis involves an infection, the lymph nodes in your armpits or under your neck can become swollen. This is a sign that your body is fighting the infection.

Swollen lymph nodes can also occur from IBC. Breast cancer often spreads to the lymph nodes in the armpits or under the neck before spreading anywhere else, which can cause them to swell.

By itself, breastfeeding isn’t a risk factor for breast cancer. But some research suggests that those who have had mastitis have an increased risk of developing breast cancer in the future.

More research is needed to explore this possible connection and learn just how much mastitis affects breast cancer risk.

Differences Between Mastitis and Breast Cancer

Despite these similarities, mastitis and breast cancer have key differences. This is true even with IBC, which tends to look the most similar to mastitis.

Mastitis and breast cancer are treated with different therapies. Mastitis is highly treatable with antibiotics, which clear the bacterial infection causing bacterial mastitis.

Other mastitis treatments aim to help reduce symptoms such as pain, swelling, and tenderness. Your doctor might suggest strategies including lymphatic drainage, over-the-counter pain relievers, or ice packs to soothe the breast. Even with home care only, mastitis usually goes away within two weeks.

Sometimes, doctors prescribe antibiotics when they think someone has mastitis. When they find that antibiotics don’t improve the symptoms, they then test for IBC. IBC won’t respond to antibiotics — it requires cancer treatments instead.

Inflammatory breast cancer treatment often starts with chemotherapy along with a mastectomy to remove the cancerous breast. Treatment might also involve radiation therapy or targeted therapy to shrink the tumor.

Doctors don’t usually recommend a lumpectomy for IBC because IBC tends to spread too quickly and malignant cells usually affect the breast skin.

Doctors use mammograms, a type of X-ray imaging test, to examine the breast tissue for signs of a tumor or other breast problems. Mammograms can be critical for diagnosing breast cancer in early stages before symptoms start.

Mammograms aren’t so useful for diagnosing mastitis. In fact, a mastitis lump won’t usually show up on a mammogram. However, a mammogram can help rule out breast cancer if you have mastitis and aren’t breastfeeding.

Mastitis is extremely common and is usually one of the first diagnoses your doctor will consider if you have unusual breast changes while breastfeeding. IBC, on the other hand, is very rare.

All types of breast cancer are very uncommon in those who are pregnant or breastfeeding. Your doctor will rule out other causes of unusual breast changes before testing you for breast cancer.

When to See a Doctor

Your doctor may encourage you to familiarize yourself with how your breasts look and feel so you can better identify unusual changes while breastfeeding. Breastfeeding tends to change the way your breasts look and feel. But you should always tell your doctor if you notice concerning changes like breast lumps, irritation, or pain.

Your doctor can examine your breasts and tell you if the changes you see are normal or abnormal. If they diagnose you with mastitis or another breast condition, they can treat you accordingly.

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