Nipple discharge

Nipple discharge refers to any fluid that leaks from one or both nipples of the breast. While it can be a normal physiological occurrence, especially in certain circumstances like pregnancy or breastfeeding, it can also indicate underlying medical conditions. The discharge can vary in color, consistency, and whether it occurs spontaneously or only when the nipple is squeezed. Evaluating nipple discharge requires careful consideration of its features, patient history, and associated symptoms.

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Causes of Nipple Discharge

1. Physiological (Normal) Causes

   • Pregnancy and breastfeeding: Colostrum or milk leakage is common during late pregnancy and lactation.

   • Galactorrhea: Non-pregnant or non-breastfeeding women may secrete milk-like discharge due to elevated prolactin levels. Causes include pituitary adenomas (prolactinomas), hypothyroidism, or medication side effects (e.g., antipsychotics, antidepressants, antihypertensives).

   • Hormonal fluctuations: Menstrual cycle changes or oral contraceptive use.

2. Pathological Causes

   • Infections and Inflammation: Mastitis or breast abscess may cause purulent (pus-like) discharge.

   • Benign breast conditions:

     • Intraductal papilloma: A small noncancerous tumor inside the milk duct, often causing clear or bloody discharge.

     • Mammary duct ectasia: Ducts beneath the nipple become widened and blocked, leading to thick, sticky, green, or black discharge.

   • Malignancy (Breast Cancer): Though less common, bloody or spontaneous unilateral discharge may indicate ductal carcinoma.

   • Endocrine and systemic conditions: Hypothyroidism, chronic renal failure, or liver disease.

3. Other Factors

   • Medications: Antipsychotics (risperidone, haloperidol), antidepressants (SSRIs, tricyclics), opioids, antihypertensives (methyldopa, verapamil).

   • Chest wall stimulation or trauma: Can lead to nipple discharge.

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Clinical Features

• Type of discharge: Milky, clear, yellow, green, brown, bloody, or purulent.

• Laterality: Unilateral (single breast) vs. bilateral (both breasts).

• Spontaneous vs. expressed: Discharge occurring without nipple compression is more concerning.

• Associated symptoms: Breast lump, pain, redness, swelling, or systemic symptoms like fever.

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Diagnosis

1. History and Examination

   • Onset, duration, type of discharge, relation to menstrual cycle, medications, pregnancy status.

   • Breast examination: presence of lumps, skin changes, tenderness.

2. Investigations

   • Laboratory tests: Serum prolactin, thyroid function tests, renal and liver function tests.

   • Imaging:

     • Mammography or breast ultrasound (for structural abnormalities).

     • MRI (in selected cases).

   • Discharge cytology: Examining the fluid under a microscope.

   • Ductography or ductoscopy: Imaging techniques to assess ductal pathology.

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Treatment

Treatment depends on the underlying cause:

1. Physiological causes

   • Reassurance if related to pregnancy, breastfeeding, or mild hormonal fluctuations.

2. Hyperprolactinemia / Galactorrhea

   • Dopamine agonists:

     • Bromocriptine (2.5–7.5 mg/day orally in divided doses).

     • Cabergoline (0.25–1 mg twice weekly orally).

   • Treat underlying pituitary adenoma (medical therapy or surgery if large).

3. Infections (Mastitis, Abscess)

   • Antibiotics: Flucloxacillin or dicloxacillin (250–500 mg every 6 hours for 7–10 days).

   • Drainage of abscess if needed.

4. Benign breast conditions

   • Intraductal papilloma: Surgical excision of the affected duct.

   • Duct ectasia: Symptomatic management, sometimes duct excision.

5. Malignancy

   • Surgical intervention, chemotherapy, radiation therapy, or hormone therapy depending on type and stage.

6. Hormonal or systemic disorders

   • Hypothyroidism: Levothyroxine replacement (typical dose 25–100 mcg daily, individualized).

   • Medication-induced: Consider discontinuing or switching offending drugs under medical guidance.

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Precautions and When to Seek Medical Attention

• Bloody, clear, or spontaneous unilateral nipple discharge.

• Discharge associated with a lump, nipple retraction, or skin dimpling.

• Persistent or recurrent discharge not linked to pregnancy or lactation.

• Discharge in men (always requires urgent evaluation).

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Drug Interactions and Considerations

• Bromocriptine and Cabergoline: Interact with macrolide antibiotics (erythromycin, clarithromycin) and certain antifungals (ketoconazole) which increase drug levels.

• Levothyroxine: Absorption reduced by calcium, iron supplements, and proton pump inhibitors.

• Antibiotics for mastitis: May interact with anticoagulants (warfarin) and oral contraceptives.