Checking Prolactin Levels in Female Patients with Nipple Discharge
Yes, you should check prolactin (and TSH) levels, but only if the nipple discharge is physiologic (bilateral, multiple ducts, non-spontaneous, white/green/yellow/clear color) rather than pathologic. 1, 2
Distinguishing Physiologic from Pathologic Discharge
The critical first step is determining whether the discharge is physiologic or pathologic, as this completely changes your workup 3, 4, 5:
Physiologic Discharge (Check Prolactin)
- Bilateral presentation 3, 4
- Multiple ducts involved 3, 4
- Non-spontaneous (only occurs with manipulation/compression) 3, 4
- White, green, yellow, or clear in color 3, 4, 2
- No associated breast mass 3
Pathologic Discharge (Do NOT Check Prolactin - Get Imaging)
- Spontaneous occurrence 3, 4, 5
- Unilateral presentation 3, 4, 5
- Single duct involvement 3, 4, 5
- Bloody, serous, or serosanguineous appearance 3, 4, 5
When to Check Pituitary Hormone Levels
For physiologic discharge (galactorrhea), check both prolactin and thyroid-stimulating hormone (TSH) levels. 2 This is the most common cause of physiologic nipple discharge not associated with pregnancy or lactation 2. Hyperprolactinemia can result from medications (particularly antipsychotics), pituitary tumors, or endocrine disorders 1.
When NOT to Check Prolactin
For pathologic discharge, skip the prolactin level and proceed directly to imaging. 3, 4, 5 The 2022 ACR Appropriateness Criteria make clear that pathologic discharge requires:
- Age ≥40 years or men ≥25 years: Diagnostic mammography or digital breast tomosynthesis (DBT) with complementary ultrasound 6, 4, 5
- Age 30-39 years: Either mammography/DBT or ultrasound as initial study, with the other as complementary 6, 4
- Age <30 years (women): Ultrasound as initial examination 6, 4, 5
Management Algorithm for Physiologic Discharge
If you've confirmed physiologic discharge and checked hormone levels:
- Young women (<40 years) with non-spontaneous, multiple-duct discharge: Observation is appropriate 3
- Patient education: Instruct to stop breast compression/manipulation 3
- No imaging required if routine screening is up to date 3, 4
- Follow-up: If discharge persists despite stopping manipulation, re-evaluate in 3-6 months 3
Critical Pitfall to Avoid
Do not order prolactin levels for pathologic discharge thinking you're being thorough—this delays appropriate imaging and potentially cancer diagnosis. 4, 5 Pathologic discharge is associated with underlying malignancy in 3-29% of cases in women and 23-57% in men 4, 5. The workup for pathologic discharge focuses on excluding intraductal papilloma (35-48% of cases), ductal ectasia (17-36%), and malignancy 4.