Read below about asymmetrical breasts, including causes, treatment options and remedies. Or get a personalized analysis of your asymmetrical breasts from our A.I. health assistant. At Buoy, we build tools that help you know what’s wrong right now and how to get the right care.

This symptom can also be referred to as:
One breast is larger than the other

A.I. Health Assistant

Take a quiz to find out why you’re having asymmetrical breasts

Take Quiz

Asymmetrical Breasts Symptoms

Having asymmetrical breasts is a very common occurrence, especially during breast development in adolescence. This typically resolves by the time the breasts are fully developed. However, 25 percent 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 benign but can also be malignant, and any lumps in women over 30 should be evaluated [1,2]. Breast exams, breast imaging, and breast biopsy are all common ways medical providers evaluate breast masses in women.

Characteristics

Symptoms that can be associated with asymmetrical breasts include:

Asymmetrical Breasts Causes Overview

Causes of asymmetrical breasts are described below from most to least common, including those related to development and masses, among others [3,4].

Development

Causes of asymmetrical breasts related to development may include the following.

  • Puberty: Asymmetry is very 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 variant: While many women with asymmetrical breasts during puberty will experience resolution of the discrepancy, about 25 percent of adult women have remaining breast asymmetry to varying degrees. This can be normal and does not necessarily reflect any underlying condition or problem.
  • 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.

Mass

Asymmetrical breasts may also be due to a mass in the breast, that can be characterized as one of the following [5].

  • 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 (a mass in the breast that you can feel). Palpable breast masses are very common, and 90 percent are benign in women between the ages of 20 and 50 [6]. 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 (unilateral), and occur in older women. Malignant masses may also present with pain, overlying skin changes, or nipple discharge.

Other

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, both from front to back and 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 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. Surgical removal of breast tissue is one cause of asymmetrical breasts.

A.I. Health Assistant Causes for Asymmetrical Breasts

The list below shows results from the use of our A.I. Health Assistant by Buoy users who experienced asymmetrical breasts. This list does not constitute medical advice.

  1. 1.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.

    2-3 weeks with treatment

    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
  2. 2.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).

    Resolves with treatment but can recur

    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
  3. 3.Breast Abscess

    A breast infection is an infection in the tissue of the breast. Breast infections are usually caused by a common bacteria, Staphylococcus aureus, found on normal skin.

    2-3 weeks with treatment

    Rarity:
    Rare
    Top Symptoms:
    nausea, breast pain, signs of breast inflammation like redness, swelling or fever, fever, chills
    Symptoms that always occur with breast abscess:
    breast pain, signs of breast inflammation like redness, swelling or fever
    Urgency:
    Primary care doctor

    Asymmetrical Breasts Checker

    Take a quiz to find out why you’re having asymmetrical breasts.

    Take Quiz
  4. 4.Scoliosis

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

    Chronic, but curable

    Rarity:
    Common
    Top Symptoms:
    spontaneous back pain, shortness of breath on exertion, asymmetrical shoulders, asymmetrical breasts, back deformity
    Urgency:
    Wait and watch
  5. 5.Breast Cancer

    Breast cancer affects one in eight women during their lives. It is caused by uncontrolled and fast growth of damaged cells in the breast tissue. These cells can also move to the lymph nodes and sometimes other organs. The main symptom of breast cancer is a hard or firm, non-mobile, usually non-tender lump in the breast that increases in size.

    Indefinite

    Rarity:
    Uncommon
    Top Symptoms:
    breast pain, armpit lump, breast mass or retraction, breast lump, nipple discharge
    Urgency:
    Primary care doctor
  6. 6.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.

    Relapsing, lasting years

    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
  7. 7.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.

    Most often, removal of the lump is needed to prevent it from becoming cancerous on the long term.

    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

Asymmetrical Breasts Treatments and Relief

If your breast asymmetry is normal or the result of surgery, this can be resolved at home with bras, padding, or inserts. Most masses in women under 30 are benign and resolve on their own; however, if you are over 30 and you notice a new mass, you should seek treatment sooner than later, especially if you believe you have an infection.

At-home treatments

Treatments for asymmetrical breasts that can be completed at home include:

  • 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.

Medical professional treatments

You should consult your physician in order to complete the following.

  • Breast exam: If you notice a new breast mass, a physician will likely perform a breast exam. They will examine the breast to look 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 likely recommend breast imaging to evaluate the cause of the mass. Mammography, breast MRI, and breast ultrasound are all common forms of breast imaging.
  • Medication: If a physician suspects your breast asymmetry is due to an infection of the breast tissue or milk ducts, they may prescribe antibiotics to treat the infection.
  • Biopsy: If a physician suspects the mass in your breast could be malignant, they may take a biopsy of the breast tissue. 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 abnormal curvature of the spine, they may suggest corrective braces to improve spinal alignment.

Seek urgent treatment for the following

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

Asymmetrical Breasts Symptom Checker Statistics

  • People who have experienced asymmetrical breasts have also experienced:

    • 12% Breast Pain
    • 2% Breast Lump
    • 2% Nipple Pain
  • People who have experienced asymmetrical breasts were most often matched with:

    • 36% Breast Infection (Mastitis)
    • 36% Breast Abscess
    • 27% Breast Cyst
  • Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

A.I. Health Assistant

Take a quiz to find out why you’re having asymmetrical breasts

Take Quiz

References

  1. Kayar R, Cilengiroglu OV. Breast Volume Asymmetry Value, Ratio, and Cancer Risk. Breast Cancer: Basic and Clinical Research. 2015;9:87-92. NCBI Link
  2. Scutt D, Lancaster GA, Manning JT. Breast Asymmetry and Predisposition to Breast Cancer. Breast Cancer Research. 2006;8(2):R14. NCBI Link
  3. Eidlitz-Markus T, Mukamel M, Haimi-Cohen Y, Amir J, Zeharia A. Breast Asymmetry During Adolescence: Physiologic and Non-Physiologic Causes. The Israel Medical Association Journal. 2010;12(4):203-206. NCBI Link
  4. Breast and Chest Wall Disorders. Children's Hospital of Philadelphia. CHOP Link
  5. Venkatesan A, Chu P, Kerlikowske K, Sickles EA, Smith-Bindman R. Positive Predictive Values of Specific Mammographic Findings According to Reader and Patient Variables. Radiology. 2009;250(3):648-657. NCBI Link
  6. Klein S. Evaluation of Palpable Breast Masses. American Family Physician. 2005;71(9):1731-1738. AAFP Link
  7. Apgar B. Is Asymmetric Breast Tissue a Sign of Malignancy? American Family Physician. 1999;60(5):1527-1528. AAFP Link
  8. Santen RJ. Benign Breast Disease in Women. NCBI. Updated May 25, 2018. NCBI Link