Nipple discharge is the release of fluid from one or both nipples, either spontaneously or when elicited by gentle pressure. It may be unilateral or bilateral, intermittent or continuous, and varies in color, consistency, and volume. Discharge can be physiologic or pathologic, and its significance depends on associated symptoms, the patient’s age, and reproductive history.

Pathophysiology

Nipple discharge results from secretion or leakage of material from the lactiferous ducts.

• Physiologic (galactorrhea) – Caused by stimulation of prolactin secretion or ductal epithelium, often due to pregnancy, breastfeeding, stress, or drugs that alter dopaminergic tone.

• Obstructive processes – Blockage or dilatation of ducts (e.g., duct ectasia, intraductal papilloma) causes accumulation of fluid, which exits through the nipple.

• Inflammatory/infective processes – Mastitis or abscess disrupt ductal integrity, producing purulent or blood-stained discharge.

• Malignant processes – Tumors (e.g., breast carcinoma, Paget’s disease) may invade ducts, creating bloody or serosanguinous discharge.

• Neuroendocrine disorders – Prolactin-secreting pituitary adenomas increase prolactin, stimulating inappropriate milk production.

Hormonal regulation involves the hypothalamic-pituitary axis. Dopamine from the hypothalamus normally inhibits prolactin; disruption (e.g., pituitary tumor, drugs) leads to galactorrhea.

History and Physical Examination

History

• Onset, duration, frequency, and laterality of discharge

• Color, consistency, and quantity

• Spontaneous vs. expressed discharge

• Associated breast changes: pain, tenderness, swelling, itching, erythema, lumps

• Gynecologic/obstetric history: menstrual cycle, pregnancies, breastfeeding history

• Use of hormones, contraceptives, or prolactin-elevating drugs

• Family history of breast cancer or endocrine disorders

Physical examination

1. Inspection

   • Examine with patient sitting (arms relaxed, raised, hands on hips, leaning forward).

   • Observe for nipple deviation, retraction, erosion, cracks, redness, or scaling.

   • Inspect for breast asymmetry, dimpling, peau d’orange, or skin discoloration.

2. Palpation

   • Palpate breasts and axillae for lumps, noting size, consistency, borders, and mobility.

   • Express discharge gently to assess duct origin and character.

Emergent considerations

• Spontaneous bloody discharge, particularly if unilateral, may suggest intraductal papilloma or malignancy.

• Discharge with fever, erythema, or breast induration indicates mastitis or abscess requiring prompt treatment.

• Rapidly enlarging breast mass or nipple ulceration warrants urgent imaging and biopsy.

Medical causes

Other causes

• Drugs: Antipsychotics (phenothiazines), tricyclic antidepressants, metoclopramide, cimetidine, methyldopa, verapamil, oral contraceptives.

• Chest wall surgery/trauma: Stimulation of thoracic nerves can trigger discharge.

• Endocrine disorders: Hypothyroidism and adrenal disease can elevate prolactin.

Special considerations

• Pediatric: Milky discharge in neonates (“witch’s milk”) is benign and due to maternal hormones; bloody discharge at menarche is rare and usually self-limiting.

• Geriatric: Any new discharge in postmenopausal women should be considered malignant until proven otherwise.

Diagnostic evaluation

• Cytology of discharge

• Breast ultrasound or mammography

• Ductography or ductoscopy if indicated

• Serum prolactin and thyroid function tests (for galactorrhea)

• Core biopsy or excision if a suspicious lesion is detected

Patient counseling

• Explain likely causes and reassure if findings are benign.

• Teach proper breast self-examination and stress routine screening (mammography as age-appropriate).

• Advise prompt review for new lumps, bloody discharge, or persistent changes.

• For galactorrhea, review medication use and advise follow-up for endocrine testing.

References

1. Aliotta HM, Schaeffer NJ. Breast conditions. In: Schuiling KD, Likis FE, editors. Women’s Gynecologic Health. Burlington, MA: Jones & Bartlett Learning; 2013. p. 377–401.

2. Berkowitz CD. Berkowitz’s Pediatrics: A Primary Care Approach. 4th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2012.

3. Buttaro TM, Tybulski J, Bailey PP, Sandberg-Cook J. Primary Care: A Collaborative Practice. St. Louis, MO: Mosby Elsevier; 2008.

4. Eberl MM, Phillips RL. Evaluation of nipple discharge. Am Fam Physician. 2004;70(11):2271–6.

5. Cardenosa G. Breast imaging companion. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2001.