01OverviewDefinition, clinical context and the essential points that orientate the chapter.
Nipple symptoms are separated by phenotype. Spontaneous unilateral clear or blood-stained fluid from one duct suggests a local intraductal process; bilateral milky multiduct secretion suggests pregnancy, lactation, a prolactin-raising medicine, hypothyroidism or another endocrine cause. Repeated squeezing can perpetuate discharge and should not be used to manufacture a diagnostic pattern.
New unilateral inversion, nipple eczema or ulceration changes urgency because tethering or Paget disease may be present even without a palpable mass. Examination documents the duct, nipple surface and retroareolar breast before age-appropriate mammography and targeted ultrasound. An image-visible lesion is sampled directly; persistent pathological discharge with negative initial imaging remains a specialist decision rather than being dismissed by negative discharge cytology.
Key points
- Establish whether discharge is spontaneous, unilateral, single-duct and clear or blood-stained; these features carry more concern than fluid produced only by squeezing several ducts.
- Ask about pregnancy, lactation, menopause, medicines that raise prolactin, breast trauma, infection symptoms and the onset of nipple inversion or eczema.
- Inspect nipple and areola for the involved duct, blood, ulceration, Paget-like change or abscess, then examine retroareolar tissue and regional nodes.
- People aged 50 or over with unilateral nipple discharge, retraction or another concerning nipple change meet the NICE suspected-cancer pathway recommendation.
- Use targeted retroareolar ultrasound and age-appropriate mammography, sampling a visible lesion rather than relying on discharge cytology to exclude cancer.
- Bilateral milky multiduct discharge directs pregnancy, medicine, prolactin and thyroid assessment, while a separate palpable or skin finding retains its own breast pathway.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Benign duct processes
Duct ectasia, intraductal papilloma and physiological secretion can cause discharge. Repeated expression may maintain multiduct fluid, while papilloma more often creates spontaneous single-duct discharge.
Malignant and endocrine causes
Ductal carcinoma in situ, invasive cancer or Paget disease may underlie pathological discharge or retraction; pregnancy, hyperprolactinaemia and dopamine-antagonist medicines can produce bilateral milk secretion.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Duct secretion and obstruction
Dilated or inflamed subareolar ducts accumulate secretions that emerge from several ducts or provoke inflammation, fibrosis and eventual nipple retraction.
- 2Intraductal bleeding
A friable papilloma or neoplastic duct lining can bleed into one duct, producing spontaneous unilateral blood-stained discharge even without a palpable mass.
- 3Tethering beneath nipple
Fibrosis, inflammation or tumour infiltration can shorten central ducts and pull the nipple inward. New unilateral distortion therefore needs structural assessment.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
Unilateral, single-duct, clear or blood-stained discharge raises concern for an intraductal lesion even when no mass is palpable.
Recent unilateral inversion or retraction requires assessment for tethering beneath the nipple; longstanding symmetrical inversion may be developmental but still needs contextual examination.
Bilateral multiduct milky discharge suggests pregnancy, lactation, medicine effect or hyperprolactinaemia; infection produces pain or erythema and requires a different urgent assessment.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Direct nipple and areolar examinationFirst step - Why
- Identify the involved duct, inversion, eczema, ulceration, mass or inflammation.
- Interpretation and limitations
- Avoid repeated forceful expression; document whether discharge is spontaneous and inspect both sides, because surface blood can arise from skin trauma.
- 02
Targeted ultrasound and mammography - Why
- Look for a retroareolar mass, duct lesion or calcification using age-appropriate imaging.
- Interpretation and limitations
- Normal imaging reduces but does not erase concern from persistent pathological discharge; the multidisciplinary team decides whether further sampling or duct evaluation is needed.
- 03
Core or vacuum-assisted biopsy - Why
- Obtain tissue from an image-visible causative lesion.
- Interpretation and limitations
- Biopsy should target the abnormality rather than the discharge alone; radiology-pathology concordance determines whether the lesion explains the symptom.
- 04
Pregnancy and endocrine testing - Why
- Investigate bilateral milky discharge when history suggests galactorrhoea.
- Interpretation and limitations
- Check pregnancy first and review dopamine-antagonist medicines; prolactin and thyroid testing are targeted, while bloody single-duct discharge follows a breast pathway.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Physiological galactorrhoea
Bilateral milky discharge from several ducts suggests pregnancy, recent lactation, medicine effect or endocrine stimulation, particularly when no focal lesion is found.
Papilloma or duct ectasia
Papilloma can cause clear or bloody single-duct discharge; duct ectasia often produces thicker multiduct discharge with subareolar discomfort or retraction.
Carcinoma or Paget disease
Persistent pathological discharge, a mass, new inversion, ulceration or unilateral nipple eczema raises concern for in-situ or invasive malignancy and requires tissue-directed assessment.
Additional chapter-specific clues
Spontaneous staining of clothing is more clinically significant than discharge produced only by repeated squeezing, which can perpetuate secretion and complicate reassessment.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01Worked case: integrated breast assessmentApply nipple discharge and inversion to a defined presentationFirst stepA 58-year-old has spontaneous blood-stained discharge from one duct of the right nipple and recently noticed slight inversion; no definite mass is palpable.+
- 1Confirm spontaneity, laterality, colour, single-duct origin, duration and medicine or lactation context; inspect for eczema, ulceration, infection and occult mass.
- 2Recognise that unilateral bloody discharge with a new nipple change meets a concerning pattern even without a palpable lump and arrange suspected-cancer pathway assessment.
- 3Obtain targeted retroareolar imaging and sample any identified lesion using the modality that visualises it; do not rely on discharge cytology to exclude malignancy.
- 4Discuss persistent symptoms with the multidisciplinary breast team when imaging is negative, because papilloma, ductal carcinoma in situ or another occult process may remain.
- 5Verify the patient receives the integrated result and has explicit instructions to report worsening bleeding, a mass or inflammatory change before scheduled review.
02Discharge classificationSort pathological from physiological patternsA patient reports fluid from a nipple but the cause and urgency are unclear.+
- 1Ask the patient to describe spontaneous staining before examining, because repeated expression can change both frequency and apparent duct number.
- 2Record laterality, duct number, colour and blood; inspect for inversion, eczema, ulceration, inflammation and a retroareolar mass.
- 3Send unilateral spontaneous single-duct clear or bloody discharge to breast imaging and tissue assessment, applying NICE age criteria and clinical judgement.
- 4For bilateral milky multiduct fluid, exclude pregnancy and review medicines before targeted endocrine tests, while retaining a safety net for focal change.
03Persistent occult-discharge pathwayManage symptoms with negative initial imagingSpontaneous unilateral bloody discharge persists although mammography and ultrasound show no definite target.+
- 1Confirm that imaging included appropriate retroareolar assessment and that the discharge truly arises from one duct rather than a bleeding skin fissure.
- 2DefinitiveDiscuss the persistent pathological pattern at the breast multidisciplinary meeting; do not treat a negative discharge cytology result as definitive exclusion.
- 3Select further imaging, duct-directed procedure or surgical assessment according to local specialist expertise and the patient’s values.
- 4DefinitiveContinue tracked review until symptoms resolve with a credible diagnosis or the breast team records a definitive management plan.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Occult cancer delay
Discharge may be the only visible sign of intraductal disease. Reassurance from absent palpability or negative cytology can postpone appropriate imaging and biopsy.
Recurrent inflammation
Stagnant duct contents and periductal inflammation can lead to repeated painful episodes, abscess or fistula, particularly when smoking-related periductal disease persists.
Skin trauma and anxiety
Repeated checking can excoriate the nipple, provoke more discharge and sustain worry; patients need a clear instruction to avoid expression and a defined review plan.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Record recurrence frequency and whether blood appears spontaneously on clothing; avoid asking the patient to express the nipple daily for monitoring.
- After endocrine intervention for galactorrhoea, review discharge, menstrual or sexual symptoms, prolactin trend where relevant and medicine changes.
- For periductal inflammation, reassess pain, erythema, collection and fistula formation; persistent inversion after inflammation settles needs renewed evaluation.
- Track every pathological-discharge referral to an integrated outcome even when no mass is present, because occult intraductal lesions may be small.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
Colour alone is insufficient
Green or milky fluid is often benign, but spontaneity, laterality, duct number and associated findings shape risk more reliably than a colour label in isolation.
Cytology has limited exclusion value
A discharge smear may not contain representative cells from an intraductal lesion. Imaging and tissue sampling of a demonstrated target provide stronger diagnostic evidence.
Inversion has a timeline
Stable bilateral inversion from development differs from new unilateral retraction caused by duct fibrosis or infiltrating tumour. Always ask when the contour changed.
Surface and duct bleeding differ
A cracked eczematous nipple can bleed externally, while intraductal blood emerges through an orifice. Careful inspection helps target punch biopsy or duct assessment appropriately.
11Common pitfallsFrequent interpretation and management errors.
- 01
Repeated forceful expression can maintain discharge and create nipple trauma, confusing whether the original symptom was spontaneous.
- 02
Calling bilateral milk secretion a breast-cancer pattern without checking pregnancy and medicines misdirects tests and increases fear.
- 03
Treating new unilateral inversion as normal anatomy without establishing its onset can miss subareolar fibrosis or malignancy.
- 04
Using a negative discharge cytology result to close persistent single-duct bloody discharge gives false reassurance from a low-yield sample.