Nipple discharge

Last updated: December 5, 2024

Summary

Nipple discharge can be physiological or pathological. Physiological discharge is typically bilateral, multiductal, with a milky appearance; causes include lactation and galactorrhea. Pathological discharge is typically unilateral, uniductal, nonmilky, and spontaneous. Although most causes of pathological nonmilky nipple discharge are benign (e.g., intraductal papilloma, mammary duct ectasia), malignancy is an important consideration. The diagnostic approach to nipple discharge is based on clinical evaluation findings, including characteristics of the discharge and patient age. Further evaluation with imaging is required for all patients with red flags in nipple discharge. Treatment depends on the underlying cause.

Nipple discharge in male individuals is not addressed in this article.

Etiology

Classification of nipple discharge ^[1]^[2]^[3]
	Physiological nipple discharge	Pathological nipple discharge
Characteristics	Bilateral discharge from multiple ducts Typically milky; may be green or clear Usually provoked (i.e., after nipple stimulation or expression)	Unilateral discharge that typically originates from a single duct Nonmilky; may be clear, bloody, or serosanguineous Usually spontaneous (i.e., occurs without nipple stimulation or expression)
Etiology	Lactation: discharge related to pregnancy or breastfeeding Galactorrhea Discharge unrelated to pregnancy or breastfeeding Caused by physiological, pharmacological, pathological or idiopathic hyperprolactinemia: ^[4]^[5]^[6] Endocrine disorders (e.g., hypothyroidism, prolactinomas) Medications (e.g., dopamine antagonists, TCAs) Chronic nipple stimulation (e.g., piercings, tight clothing) See “Etiology of hyperprolactinemia” for details.	Benign breast conditions Intraductal papilloma (most common) ^[7] Mammary duct ectasia Fibrocystic breast changes Breast abscess Malignancy (5–15% of cases): most commonly ductal carcinoma in situ ^[7]

Intraductal papilloma is the most common cause of pathological nipple discharge accounting for up to 58% of cases. ^[7]

Clinical evaluation

Focused history ^[1]^[2]

Nature of discharge (e.g., color, laterality, spontaneous vs. provoked)
Obstetric history (e.g., time since last pregnancy and breastfeeding)
Medication review for drugs that can cause galactorrhea (see “Etiology of hyperprolactinemia”)
Nipple stimulation (e.g., from tight-fitting clothing or during sexual activity)

Focused examination ^[1]^[2]

Perform a clinical breast examination to assess for:

Palpable breast mass
Visible nipple discharge (spontaneous or after expression)
Characteristics of nipple discharge (e.g., color, involvement of single or multiple ducts)

Red flags in nipple discharge ^[1]^[2]

The following are red flag features for malignancy.

Characteristics of pathological nipple discharge
- Unilateral
- Uniductal
- Persistent
- Spontaneous
- Clear, bloody, or serosanguineous
Breast mass
Risk factors for breast cancer (e.g., advanced age, positive family history)

Diagnosis

Initial diagnostic approach ^[1]^[2]^[3]

Perform a focused clinical evaluation in all patients, including for red flags in nipple discharge.

Presence of red flags

Breast mass: Obtain initial diagnostics for a palpable breast mass and manage accordingly.
Other red flags in nipple discharge
- Patients ≥ 30 years of age ; ^[2]^[3]
  - Ultrasonography
  - AND diagnostic mammography or digital breast tomosynthesis (DBT)
- Patients < 30 years of age
  - Ultrasonography
  - Consider diagnostic mammography or DBT. ^[1]

No red flags

Perform evaluation based on the characteristics of the discharge.

Bilateral milky discharge
- All patients: pregnancy test
- If pregnancy test is negative, perform diagnostics for hyperprolactinemia (e.g., serum prolactin and TSH levels).
Nonmilky discharge
- Patients aged ≥ 40 years ^[1]
  - Ultrasonography
  - AND diagnostic mammography or DBT
- Patients aged < 40 years: Advise avoidance of nipple stimulation and reassess in 3 months.

Additional studies ^[1]^[2]^[3]

Indications
- Diagnostic uncertainty
- Follow-up of abnormal findings on initial imaging
- Preprocedural planning
Modalities

Biopsy is necessary if imaging findings are concerning for malignancy (e.g., BI-RADS 4 or 5). ^[2]

Common causes

Common causes of nipple discharge ^[1]^[2]
	Distinguishing clinical features	Diagnostic findings	Management
Pregnancy and breastfeeding	Bilateral milky discharge Clinical features of pregnancy	Positive pregnancy test	See “Prenatal care” and “Breastfeeding.”
Galactorrhea	Milky discharge in the absence of pregnancy or breastfeeding	↑ Serum prolactin (in hyperprolactinemia) ^[1]^[5]^[6] Additional findings depending on the underlying etiology (e.g., ↓ TSH in hypothyroidism) See “Diagnostics for hyperprolactinemia.”	Avoid nipple stimulation. Treat the underlying cause, e.g., Stop triggering medications, if possible. Treat hypothyroidism. See “Treatment of hyperprolactinemia.”
Intraductal papilloma	Bloody or serous nipple discharge Palpable retroareolar mass	Well-defined solid nodule or mass within a dilated lactiferous duct on ultrasound ^[3]^[8]	Duct excision ^[9] See “Treatment of intraductal papilloma.”
Mammary duct ectasia	Gray, greenish, or bloody discharge ^[7] Nipple inversion Palpable retroareolar mass	Dilated subareolar ducts on ultrasound or mammography ^[10]	Expectant management is often sufficient. Duct excision in certain individuals See “Treatment of mammary duct ectasia.”
Breast cancer	Clinical features of breast cancer (e.g., breast mass, blood-tinged discharge)	See “Benign vs. malignant lesion on breast ultrasound” and “Benign vs. malignant lesion on mammography.”	See “Treatment of breast cancer.”
Fibrocystic breast changes	Cyclic mastalgia Palpable breast nodules Clear or slightly milky discharge	Cysts, distorted breast parenchyma, and/or calcifications on ultrasound or mammography ^[11]^[12]	Nonproliferative: management of breast cysts Proliferative: surgical excision See “Treatment of fibrocystic breast changes.”
Breast abscess	Breast pain, erythema, and edema Purulent discharge Fluctuant mass on palpation	Irregular, hypoechoic fluid-filled lesions on ultrasound ^[13]^[14]	Drainage, antibiotics, and pain management See “Treatment of breast abscess.”

Treatment

Treatment is based on the underlying cause; see “Common causes of nipple discharge.” ^[1]^[2]

Physiological nipple discharge
- Lactation: Advise patients that milky discharge may continue for one year after the end of pregnancy or breastfeeding.
- Galactorrhea
  - Physiological hyperprolactinemia: Advise avoidance of nipple stimulation and reassess in 3 months.
  - Pathological or pharmacological hyperprolactinemia: See “Treatment of hyperprolactinemia.”
Pathological nipple discharge
- Concern for malignancy: Management is based on biopsy results; consult appropriate specialists.
- For all other patients (e.g., with BI-RADS 1–3 on imaging), consider either:
  - Duct excision
  - Clinical and imaging surveillance for 24 months ^[1]^[2]

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