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Breast Asymmetry: Causes, How Common It Is, and Treatment Options

Two brown breasts with darker brown heart-shaped nipples. The left one is a circle, the right is a longer oval.
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Last updated April 15, 2022

Breast asymmetry quiz

Take a quiz to find out what's causing your breast asymmetry.

Understand asymmetrical breasts symptoms, including 7 causes & common questions.

12 most common cause(s)

Breast asymmetry quiz

Take a quiz to find out what's causing your breast asymmetry.

Take breast asymmetry quiz

Asymmetrical breasts symptoms

Having asymmetrical breasts is very common, especially during breast development in adolescence. This typically resolves by the time the breasts are fully developed. However, 25% of women have some breast asymmetry their whole lives, which is perfectly normal and not necessarily indicative of an underlying condition. In women who do have more significant differences, these can be related to structural variances or lumps. Most breast lumps in women under 50 are usually benign, but any lumps in women over 30 should be evaluated. Breast exams, breast imaging, and breast biopsy are all common ways physicians evaluate breast masses in women.

Common accompanying symptoms of asymmetrical breasts

Symptoms that can be associated with asymmetrical breasts include:

Asymmetrical breasts causes

The following details may help you better understand your symptoms. If your breast asymmetry becomes more apparent or bothersome, you should see a physician.

Developmental causes

Asymmetrical breasts may be due to developmental reasons, such as the following.

  • Puberty: Asymmetry is common during the development of breasts in adolescence. Commonly, breast asymmetry resolves by the time breasts are fully developed, which typically happens by age 18. The final degree of breast asymmetry cannot be determined until this time.
  • Normal variation: Many women have asymmetrical breasts during puberty, and about 25% of these women will have lasting asymmetry into adulthood.
  • Prepubescent injury: Injury to breast tissue before it has fully developed can lead to breast asymmetry. Trauma, infection, or radiation to one side of the chest are possible injuries that might lead to asymmetric breast growth.

Growths or masses

Asymmetrical breasts may also be due to a mass in the breast, that can be characterized as one of the following.

  • Infection: A breast abscess typically presents as a palpable, swollen mass in one breast with pain, redness, and warmth. Typically, a breast abscess is caused by a bacterial infection. The milk ducts in the breast can also become infected, which is common among women who are breastfeeding.
  • Benign breast mass: Breast asymmetry may be due to a palpable breast mass, or a mass in the breast that you can feel. Palpable breast masses are common, and 90% are benign in women 20 to 50 years old. In women under 30, breast masses are commonly bilateral and resolve on their own. Some possible types of benign breast masses include fibrous changes with the menstrual cycle, cysts, or tissue damage following trauma to the breast.
  • Malignant breast mass: There are multiple different types of invasive and noninvasive breast cancer that may be the cause of a breast mass. Typically, malignant breast masses are hard, present in one breast, and occur in older women. Malignant masses may also cause pain, overlying skin changes, or nipple discharge.

Other causes

Other causes that may result in breast asymmetry include the following.

  • Skeletal abnormality: Breasts may appear asymmetric due to abnormalities of the bones in the spine or ribs. Rib abnormalities such as fracture or deformity may change the shape of the chest wall, leading to asymmetry.
  • Curved spine: Scoliosis is a condition where the spine curves more than usual, either from front to back or from right to left. Severe scoliosis can rotate the torso and give the breasts the appearance of asymmetry even if they are the same size. Scoliosis commonly develops in adolescence.
  • Surgical changes: Lumpectomy, removal of part of the breast tissue, or a mastectomy, removal of the entire breast, are common treatments for breast cancer. Some women choose to have reconstructive surgery to maintain breast symmetry, while others do not.

7 asymmetrical breasts conditions

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

Symptoms of menopause

Menopause, or "change of life," refers to the time when a woman no longer has menstrual cycles and can no longer bear children.

It is a normal occurrence and usual happens between ages 45 to 55. Menopause can be artificially induced by surgical removal of both ovaries, and by chemotherapy and/or radiation therapy for cancer.

Symptoms usually begin many months before periods actually stop. There will be irregular periods, vaginal dryness, hot flashes, weight gain from slower metabolism, and dry skin.

If not treated, some symptoms may affect quality of life. Hot flashes and hormonal imbalances can disrupt sleep, sexual function, and emotional health.

At menopause, risks of heart disease, osteoporosis, and urinary incontinence increase. Because periods can become irregular while pregnancy is still possible, testing is advisable before any medical treatment is done.

Menopause is diagnosed when an entire year has gone by without the woman experiencing a menstrual period. Blood testing for hormone levels can confirm menopause.

Treatment can be done for any troublesome symptoms, including hormone replacement therapy to ease hot flashes.


Scoliosis causes a sideways curve of your backbone, or spine. is most common in late childhood and the early teens, when children grow fast.

You do not need treatment as most curves are mild. However checkups with your physician may be needed to see if there are any changes, which at that time may require a brace or if more severe, surgery.

Rarity: Common

Top Symptoms: spontaneous back pain, shortness of breath on exertion, asymmetrical shoulders, asymmetrical breasts, back deformity

Urgency: Wait and watch

Premenstrual syndrome

Premenstrual syndrome, or PMS, refers to a set of symptoms experienced by some women just before the start of a menstrual period.

The exact cause of PMS is uncertain, but changing hormone levels are always involved. Ongoing depression will make the symptoms worse and may be connected to low levels of the brain chemical serotonin, which influences mood, food cravings, and sleep patterns.

Symptoms include irritability, mood swings, insomnia, difficulty concentrating, weight gain, fluid retention, bloating, abdominal discomfort, food cravings, and breast tenderness.

PMS normally fades within a day or two of start of the menstrual period. If the symptoms are interfering with activities of daily living, a medical provider may be able to help. Some symptoms can be treated for improved quality of life.

Diagnosis is made through patient history.

Treatment primarily involves making lifestyle improvements in diet, exercise, and stress management. Nonsteroidal anti-inflammatory drugs can address the physical discomfort, and diuretics will help with fluid retention. Hormone-based contraceptives can regulate the cycle and ease symptoms. In some cases, antidepressants are helpful.

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.

Intraductal papilloma

Breast problems such as lumps are very common and often not caused by breast cancer. An intraductal papilloma is such a benign breast lump situated in the milk ducts.

All new breast lumps should be examined by a doctor to determine if further testing is needed, so the best thing to do is to make an appointment with your primary care physician.

Rarity: Uncommon

Top Symptoms: breast lump, painful breast lump, painless breast lump, white or clear fluid leaking from the breast, nipple lump

Symptoms that never occur with intraductal papilloma: armpit lump

Urgency: Primary care doctor

High prolactin hormone level

Hyperprolactinemia means the pituitary gland secretes too much prolactin, the hormone responsible for producing milk in a new mother. The condition can appear in both women and men.

It can be caused by pregnancy; by an ovulatory disorder; by some psychiatric medications; or by a prolactin-secreting tumor of the pituitary (prolactinoma.)

Women with other reproductive disorders, such as polycystic ovary syndrome (PCOS,) are most susceptible. Hyperprolactinemia is also seen in those with hypothyroidism and chronic renal failure. Many patients on hemodialysis have elevated prolactin levels.

Symptoms in both women and men include reduced libido (sex drive) and infertility. Men may show breast enlargement and women may develop breast milk.

If not treated, hyperprolactinemia can result in loss of bone density in both women and men.

Diagnosis is made through blood testing to measure hormone levels, and sometimes MRI of the pituitary gland underneath the brain.

Treatment may include "watchful waiting," or a period spent observing the symptoms to see if they change; drug therapy; or surgery.

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.

You should visit your primary care physician to evaluate the lump. Diagnosis typically just involves a physical exam and imaging. A biopsy would be needed in case scarier things need to be ruled out, but it's not always necessary. Treatment of a cyst involves aspirating the contents of the cyst, a mass just needs a biopsy with no further treatment, and nipple discharge doesn't require treatment.

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


Fibroadenomas are solid, noncancerous breast tumors that occur most often in adolescent girls and women under the age of 30. You might describe a fibroadenoma as firm, smooth, rubbery or hard with a well-defined shape.

You should visit your primary care physician to confirm the diagnosis and discuss treatment options.

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.

You should visit your primary care physician to confirm the diagnosis and discuss treatment options, such as antibiotics.

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

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).

You should visit your primary care physician within the next 24 hours to evaluate the lump. Diagnosis typically just involves a physical exam and imaging. Sometimes a biopsy is needed to rule out other causes. Treatment of a cyst involves aspirating the contents of the cyst (sucking the stuff out).

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 cancer

Breast cancer has several names, depending on the part of the breast where it starts:

  • Lobular carcinoma affects the milk glands.
  • Ductal carcinoma affects the milk ducts.
  • Sarcoma affects the connective tissue.
  • Paget's Disease affects the nipple and areola.

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

Breast abscess

Breast abscess is a complication of mastitis, which is an inflammation of the breast tissue. An abscess is a pocket of pus that forms within the breast, usually just under the skin.

Most susceptible are women who are breastfeeding. Bacteria can be transferred into the milk ducts from the skin or from the infant's mouth. Women not breastfeeding can be infected through a sore nipple or from a nipple piercing.

If a milk duct is blocked through trauma, compression, or incomplete emptying, bacteria can gain a foothold and an abscess can form.

The abscess forms a hot, reddened, painful lump in the breast. There will be flu-like symptoms of fever, chills, fatigue, and body aches.

Diagnosis is made through physical examination and sometimes a milk sample.

Treatment is with antibiotics along with rest, fluids, and over-the-counter pain relievers. Unless otherwise directed by the medical provider, it is safe to continue nursing the baby. If the abscess persists, it may be drained under local anesthesia with a needle and syringe.

Asymmetrical breasts treatments and relief

Some cases of breast asymmetry are treatable at home. Most masses in women under 30 are benign and resolve on their own. If you are over 30 and you notice a new mass, you should see a doctor, especially if you believe you have an infection.

At-home treatments

The following treatments for asymmetrical breasts can be completed at home.

  • Bras, padding, or inserts: Bras with padding on one side can improve the appearance of asymmetrical breasts. This is especially helpful for adolescents who are self-conscious about breast asymmetry while their breasts are still developing. This is also helpful for people with post-surgical asymmetry due to lumpectomy or mastectomy.
  • Observation If you are under the age of 30 and notice a new breast mass, it is most likely benign. A physician may suggest you monitor the lump at home over the course of several menstrual cycles to see if it changes or resolves on its own.

When to see a doctor

If your breast asymmetry is bothersome, you should consult your physician to discuss or complete the following.

  • Breast exam: Your physician will examine the breast for abnormalities, and palpate both breasts and the area underneath your armpits to feel for abnormalities.
  • Imaging: If you have a new breast mass and are over the age of 30, a physician will recommend imaging. Mammography, breast MRI, and breast ultrasound are all common forms of breast imaging.
  • Medication: Your physician will prescribe antibiotics for an infection.
  • Biopsy: A biopsy is when a small piece of tissue is removed from the body to determine the cause of disease.
  • Bracing: If a physician suspects your breast asymmetry is due to an abnormal curvature of your spine, they may suggest corrective braces to improve spinal alignment.

When it is an emergency

If any of the following apply, you should seek immediate treatment:

  • You are over the age of 30 and notice a new breast lump
  • You suspect you may have an infection in your breast
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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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