Breast Swelling Symptoms, Causes & Common Questions

Understand your breast swelling symptoms, including 9 causes & common questions.

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  1. Symptoms
  2. Causes
  3. 9 Possible Breast Swelling Conditions
  4. Treatments and Relief
  5. Real-Life Stories
  6. FAQs
  7. Questions Your Doctor May Ask
  8. Statistics
  9. Related Articles
  10. References

Breast Swelling Symptoms

Unexplained breast swelling can cause concern and discomfort. There are plenty of reasons for breast swelling, however, that aren't dangerous and are even considered normal.

Common characteristics of breast swelling

If you're experiencing breast swelling it can likely be described by the following.

Breast function and structure

Breasts describe the tissue over the pectoral muscles that serve as the mammary gland in women. Breast tissue produces milk along with fatty tissue, and the amount of fat produced by the breast determines its size. The part of the breast that produces milk is made up of 15 to 20 sections. These sections, called lobes, are smaller structures that produce milk [1]. The liquid travels to the nipples through ducts. Breasts also contain connective tissue and ligaments along with nerves, blood vessels, and lymph nodes.

Breast changes throughout life

Obviously, breasts go through a variety of changes throughout your life [2]. It's normal for breasts to change in size, appearance, and shape over time. The same changes that can be classified as normal can also signify serious conditions. Therefore, it's important for you to perform breast self-examinations and inform your doctor of any concerning changes as soon as possible.

Breast Swelling Causes

Any changes in the breasts should be monitored. However, the good news is that the majority of breast swelling concerns can be explained by a cause that isn't linked to a serious medical issue [3,4]. The following details may help you better understand your symptoms. See a physician for breast swelling that worsens or persists.

Infectious causes

Infectious causes are one reason for breast swelling. If there is a crack in the skin or the breast is poked with a contaminated object, both bacterial and fungal infections are possible. Infections can also enter through the nipple.

Traumatic causes

Traumatic causes include physical injury. There are a variety of ways breast injury can occur. One of the most traumatic is a car accident or other intense force. However, something as simple as bumping into a sharp corner or wearing tight clothing can cause breast swelling.

Medical causes

Medical causes can be behind swelling in the breast. Breast cancer is the most serious possibility, but swelling alone is not reason enough to believe cancer is present. If there are also lumps in the breast, a check-up is always recommended, but keep in mind that there are medical conditions that cause benign breast lumps.

Other causes

In these situations, swelling is expected and not an immediate cause for concern. Other causes of breast swelling include:

  • Premenstrual syndrome
  • Water retention
  • Pregnancy
  • Birth control pills

9 Possible Breast Swelling Conditions

The list below shows results from the use of our quiz by Buoy users who experienced breast swelling. This list does not constitute medical advice and may not accurately represent what you have.

Breast infection (mastitis)

Mastitis is an infection of the breast tissue that results in breast pain, swelling, warmth and redness of the breast. Mastitis most commonly affects women who are breast-feeding (lactation mastitis), although sometimes this condition can occur in women who aren't breast-feeding.

Rarity: Uncommon

Top Symptoms: fatigue, nausea, breast pain, signs of breast inflammation like redness, swelling or fever, fever

Symptoms that always occur with breast infection (mastitis): breast pain, signs of breast inflammation like redness, swelling or fever

Urgency: Primary care doctor

Plugged breast duct

If you're making milk faster than it's getting expressed, it can get backed up in the duct. When this happens, the tissue around the duct may become swollen and inflamed and press on the duct, causing a blockage.

Rarity: Uncommon

Top Symptoms: breast pain, breast lump, painful breast lump

Symptoms that never occur with plugged breast duct: fever, breast redness

Urgency: Primary care doctor

Breast cyst

A breast cyst is a fluid-filled sac (like a tiny balloon) inside the breast. Breast cysts are common in women. They might cause a little pain, but they are usually benign (not cancerous).

Rarity: Common

Top Symptoms: breast pain, breast lump, painful breast lump, movable breast lump

Symptoms that always occur with breast cyst: breast lump

Symptoms that never occur with breast cyst: armpit lump, fever

Urgency: Primary care doctor

Breast abscess

A breast abscess is a collection of infected fluid, or pus, within the breast that is generally painful, and may cause fever, chills, fatigue, and body aches.

A breast abscess is a complication of mastitis, an infection of the breast tissue, that develops most commonly in breastfeeding women. ...

Read more

Breast Swelling Symptom Checker

Take a quiz to find out what might be causing your breast swelling

Fibrocystic breast changes

Fibrocystic change is a generalized term used to describe a variety of benign changes in the breast. Symptoms of this condition are breast swelling or pain, as well as nodules, lumpiness, or nipple discharge.

Rarity: Common

Top Symptoms: breast lump, hard breast lump, nipple discharge, rope-like breast lump

Symptoms that always occur with fibrocystic breast changes: breast lump

Urgency: Primary care doctor

Premenstrual syndrome

Premenstrual syndrome (PMS) is a condition that can produce emotional and physical symptoms in women in the days leading up to their menstrual cycle. Common symptoms include bloating, cramping, headaches, irritability, fatigue, and sleep and appetite changes. These symptoms...

Read more

Non-specific breast pain

Nonspecific breast pain, also called mastalgia or mastodynia, refers to tenderness or pain in the breast with no obvious cause. It almost always proves to have a benign (non-cancerous) cause.

Breast pain is most common in women aged 35 to 50 and still experiencing menstruation. Fibrocystic changes are common in this age group, where tiny, fluid-filled sacs form within breast tissue and might be felt as small, tender, but non-cancerous lumps.

Birth control pills, hormone replacement therapy, caffeine, and soy can cause breast tenderness in women of any age. A breast infection can cause painful lumps.

A medical provider should be seen, in order to rule out any serious condition and get treatment for the discomfort.

Diagnosis is made through patient history; physical examination; mammogram or breast ultrasound; and sometimes biopsy.

A breast infection will be treated with antibiotics. Large, painful cysts may have the fluid drained or be surgically removed. Lifestyle improvements regarding diet and exercise are often helpful, as well as adjustments to birth control pills or hormone therapy.

Rarity: Common

Top Symptoms: breast pain, breast swelling, armpit pain

Symptoms that always occur with non-specific breast pain: breast pain

Urgency: Primary care doctor

Breast cancer

There are several types of breast cancer, depending on the part of the breast where it starts. The most common types are ductal carcinoma in situ (DCIS), invasive ductal carcinoma and invasive lobular carcinoma.

Women over age 50 with a family history of the disease, and/or certain genetic factors, are most at risk, but anyone can get breast cancer at any age. It is rare in men but does occur.

Symptoms include a lump, thickening, or pain anywhere in the breast or armpit; red, flaky, or irritated breast or nipple skin; nipple discharge; and any area of irregular skin or misshapenness.

Many harmless conditions can cause similar signs, so it is important to see a medical provider about any of these symptoms.

Diagnosis is made through physical examination; imaging such as ultrasound, mammogram, or MRI; and sometimes biopsy.

Treatment involves a combination of surgery, radiation therapy, and chemotherapy.

The best prevention is a combination of screening mammograms as recommended by the medical provider, and monthly self-examination.

Rarity: Uncommon

Top Symptoms: breast pain, armpit lump, breast mass or retraction, breast lump, nipple discharge

Urgency: Primary care doctor

Possible pregnancy

The earliest sign of pregnancy is typically a missed period, but many women do experience symptoms shortly after conception:

  • Implantation bleeding may occur after six to twelve days, when the fertilized egg implants itself into the lining of the uterus. This can cause mild cramping with light bleeding or spotting.
  • Fatigue and increased desire to sleep may happen within a week.
  • Breast tenderness can start as soon as one to two weeks.
  • Nausea ("morning sickness") can occur after two to eight weeks.

If pregnancy is suspected, testing should be done so that proper prenatal care can begin. It's important to avoid some behaviors during pregnancy, such as drinking alcohol or using certain drugs or medications, so an early diagnosis should be made.

Over-the-counter home pregnancy tests are available at any drugstore. A positive test is almost certainly correct, but a negative test in the face of other symptoms may be a false negative and should be tried again after a week.

Rarity: Common

Top Symptoms: fatigue, nausea or vomiting, stomach bloating, bloody vaginal discharge, vaginal bleeding

Symptoms that always occur with possible pregnancy: missed period

Symptoms that never occur with possible pregnancy: painful urination, severe abdominal pain

Urgency: Self-treatment

Breast Swelling Treatments and Relief

When to see a doctor

Breast swelling can be a normal occurrence. If you have a history of breast diseases in your family or have reason to believe there is a serious cause behind your discomfort, it's always best to seek medical advice, especially if you notice any of the following.

At-home treatments

If you believe the cause of your breast swelling is related to a non-serious cause, there are a few at-home treatments you can try to relieve any associated discomfort. However, if the swelling worsens or persists, consult your doctor.

  • Supportive clothing: If you believe tight, ill-fitting clothing is behind your breast swelling, switch to supportive bras and looser shirts to see if there's a change.
  • Ice or heat: If an injury is behind your breast swelling, try applying ice or heat for relief.
  • Change of pills or medication: For hormonal causes, discuss switching medications with your doctor. If contraceptives are the cause of the swelling, you might be able to try a different brand.
  • Over-the-counter medications: Pain-relieving medications can also relieve swelling if the cause behind them isn't related to a serious underlying condition like cancer.

Real-life Stories

Once your story is reviewed and approved by our editors, it will live on Buoy as a helpful resource for anyone who may be dealing with something similar. If you want to learn more, try Buoy Assistant.

FAQs About Breast Swelling

Here are some frequently asked questions about breast swelling.

Do breasts swell before your period?

Yes, breast swelling in sync with a menstrual cycle is normal [5]. It frequently involves both breasts and is caused by alteration of ducts within the breast tissue. In response to the hormones released just prior to a menstrual period, a woman's body begins some very early changes that prepare it for a child. One of these changes involves the development of breast tissue in preparation for milk production and delivery. This can cause intermittent breast swelling. If you have breast swelling that occurs out of sync with your period, you should seek medical evaluation.

Are swollen breasts a sign of pregnancy?

Yes. Breasts can swell early in pregnancy. They can swell within one or two weeks of pregnancy or become tender. Swollen breasts can also occur closer to birth as the body prepares milk. Breast swelling is one of the most common early signs of pregnancy. If you suspect you are pregnant, you should either seek medical evaluation or take an over-the-counter pregnancy test.

Why do I only have one swollen breast?

One swollen breast can be a sign of a benign or malignant tumor, a nipple or milk duct infection if you are breastfeeding, or cyclical changes. If you have one swollen breast that does not swell in sync with your menstrual period, you should consider being examined by your physician.

Can a swollen breast be a result of breastfeeding (breast engorgement)?

Yes, breastfeeding can lead to mastitis or swelling of the breast from infection, usually from a baby's mouth. The most common and appropriate treatment is to continue to breastfeed and take anti-inflammatory pain medication, keep your infant's gums clean, and perhaps ask your physician about an antibiotic.

When should you seek medical attention for swollen breasts?

When swelling persists out of sync with your period or is accompanied by a fever, pus, or redness, you should see a physician. Swelling of both breasts is less worrisome than swelling of one breast. If you have other symptoms like a prolonged cough, fever, or chills, you should seek medical attention. If you have a diffuse rash or bleeding from the nipple you should also seek medical attention.

Questions Your Doctor May Ask About Breast Swelling

To diagnose this condition, your doctor would likely ask the following questions:

  • Are you sexually active?
  • Do you feel pain when you urinate?
  • Do you currently use estrogen as a hormone replacement therapy?
  • Do you currently smoke?

If you've answered yes to one or more of these questions

Breast Swelling Symptom Checker

Take a quiz to find out what might be causing your breast swelling

Breast Swelling Symptom Checker Statistics

People who have experienced breast swelling have also experienced:

  • 16% Breast Pain
  • 9% Bloody Vaginal Discharge
  • 5% Vaginal Bleeding

People who have experienced breast swelling were most often matched with:

  • 40% Breast Infection (Mastitis)
  • 30% Plugged Breast Duct
  • 30% Breast Cyst

People who have experienced breast swelling had symptoms persist for:

  • 41% Less than a week
  • 16% Over a month
  • 16% One to two weeks

Source: Aggregated and anonymized results from Buoy Assistant (a.k.a. the quiz).

Breast Swelling Symptom Checker

Take a quiz to find out what might be causing your breast swelling


  1. Breast Anatomy and How Cancer Starts. National Breast Cancer Foundation. NBCF Link
  2. Normal Breast Development and Changes. Johns Hopkins Medicine. Johns Hopkins Medicine Link
  3. Breast Pain: Not Just a Premenopausal Complaint. Harvard Medical School: Harvard Health Publishing. Updated June 19, 2018. Harvard Health Publishing Link
  4. Staradub VL. Patient Education: Common Breast Problems (Beyond the Basics). UpToDate. Updated June 8, 2017. UpToDate Link
  5. Vorvick LJ. Premenstrual Breast Changes. U.S. National Library of Medicine: MedlinePlus. Updated May 21, 2016. MedlinePlus Link
  6. Simon S. Breast Cancer Symptoms: What You Need to Know. American Cancer Society. Published September 27, 2018. American Cancer Society Link

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