Periductal Mastitis (Non-Lactational)
Summary
Periductal Mastitis (PDM) is a chronic inflammatory condition of the subareolar ducts, predominantly affecting women of reproductive age. It is distinct from simple Duct Ectasia. It is primarily a disease of Smokers (>90% association). The pathophysiology involves squamous metaplasia of the lactiferous ducts, leading to keratin plugging, duct rupture, and secondary infection (often Anaerobic). It presents as a recurrent subareolar abscess or a Mammary Duct Fistula. [1,2]
Clinical Pearls
The "Zuska's Disease" Triad: The classic clinical picture is: > 1. Recurrent Retroareolar Abscess. > 2. Intermittent purulent discharge. > 3. A cutaneous fistula at the border of the areola.
Smoking Gun: Asking a patient with periductal mastitis to stop smoking is not just "good advice" – it is the primary treatment. Surgery has a >50% failure/recurrence rate in patients who continue to smoke, due to poor microvascular healing and continued duct damage.
Anaerobic Smell: The pus from a PDM abscess is often foul-smelling, reflecting the polymicrobial anaerobic flora (Bacteroides, Peptostreptococcus) rather than the pure Staph aureus of lactational mastitis.
Demographics
- Prevalence: 5-9% of women.
- Age: Mean age 32 years (younger than Duct Ectasia).
- Risk Factors:
- Smoking: RR > 10.
- Nipple Piercing: Traumatic entry.
- Obesity.
Mechanism (Squamous Metaplasia)
- Metaplasia: Toxins in cigarette smoke induce the normal cuboidal epithelium of the lactiferous ducts to transform into Squamous Epithelium (skin).
- Obstruction: These squamous cells shed Keratin, which cannot drain. Keratin plugs block the duct.
- Duct Ectasia: The duct dilates behind the blockage.
- Rupture: The duct wall bursts, spilling keratin into the periductal tissue.
- Inflammation: Keratin is chemically irritant -> Granulomatous reaction (Giant Cells).
- Infection: Secondary colonization by anaerobes creates an abscess.
- Fistula: The abscess tracks to the skin surface (usually at the areolar edge) to drain.
| Condition | Age | Cause | Features |
|---|---|---|---|
| Periductal Mastitis | 30s | Smoking | Recurrent abscess, Fistula, Anaerobes. |
| Duct Ectasia | 50s | Involution | Green/Black discharge, Slit-like nipple retraction. |
| Lactational Mastitis | 20s-30s | Stasis | Breastfeeding history. Systemic fever. |
| Breast Cancer | >50s | Malignancy | Hard irregular mass. Bloody discharge. |
Acute
Chronic
Imaging
- Ultrasound: First line. Confirms abscess cavity vs solid mass.
- Mammogram: If >35 years. Shows retroareolar density or calcifications (may look suspicious).
- MRI: Useful for mapping complex fistula tracks.
Tissue Diagnosis
- Needle Core Biopsy: MANDATORY for any solid mass or chronic induration to exclude carcinoma.
- Pus Swab: Often yields mixed anaerobes.
Management Algorithm
SUBAREOLAR ABSCESS / MASTITIS
↓
IS PATIENT LACTATING?
┌─────────┴─────────┐
YES NO
(Treat as Lactational) ↓
IS IT AN ABSCESS?
(Ultrasound)
↓
**STOP SMOKING** (Counseling)
┌─────────┴─────────┐
ACUTE ABSCESS CHRONIC/RECURRENT
↓ ↓
• Aspiration (US) • **Total Duct Excision**
• Antibiotics (Hadfield's Op)
(Co-Amoxiclav - Removes all ducts
+ Metronidazole) - Disconnects nipple
- Cures the problem
Medical Therapy
- Antibiotics: Co-Amoxiclav (Augmentin) is first line (covers Staph + Anaerobes). Addition of Metronidazole is wise for foul-smelling pus.
- Aspiration: Preferred over Incision & Drainage (I&D). I&D often results in a persistent fistula in this condition.
Surgical Therapy (Definitive)
- Total Duct Excision (Hadfield's / Adair's Procedure):
- Indicated for recurrent abscesses or chronic fistula.
- Involves a circumareolar incision, dissecting the nipple flap, and removing the entire cone of retroareolar ducts.
- Note: The patient loses the ability to breastfeed from that breast. Sensation is usually preserved.
- Mammary Duct Fistula: Persistent drainage.
- Nipple Inversion: Permanent cosmetic deformity.
- Sepsis: Rare, but possible in diabetics.
- High Recurrence: 50% recurrence rate if the patient continues to smoke.
- Benign: Not a risk factor for breast cancer (although the symptoms can mimic it).
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| Breast Infection | ABS (Assoc Breast Surgery) | Ultrasound assessment. Antibiotic choice. |
| Benign Breast Disease | ASBS (USA) | Smoking cessation mandates. |
Landmark Evidence
1. Dixon et al (Br J Surg 1996)
- The seminal paper distinguishing Periductal Mastitis (Inflammatory/Smoking) from Duct Ectasia (Involutional/Ageing) as two separate pathological entities.
What is Periductal Mastitis?
It is a persistent inflammation of the milk ducts behind the nipple. It causes painful lumps (abscesses) and discharge, even though you are not breastfeeding.
Is it caused by smoking?
Yes. It is almost exclusively a disease of smokers. The chemicals in cigarettes damage the lining of the breast ducts, turning them from smooth tubes into rough, blocked tubes (a bit like skin). When these blockages burst, they cause repeated infections.
Can you cure it?
We can treat the infection with antibiotics, but it often comes back. The only way to stop it permanently is to:
- Stop Smoking: This allows the ducts to heal.
- Surgery: If it keeps returning, we have to perform an operation to remove all the milk ducts behind the nipple. This stops the infections but means you cannot breastfeed from that side in the future.
Is it cancer?
No. It is a benign inflammation. However, because it causes lumps and nipple changes, we often do biopsies just to be 100% sure.
Primary Sources
- Dixon JM, et al. Periductal mastitis and duct ectasia: different conditions with different aetiologies. Br J Surg. 1996.
- Gollapalli V, et al. Smoking and recurrent subareolar breast abscess. J Am Coll Surg. 2011.
- Versluijs-Ossewaarde FN, et al. Subareolar breast abscesses: characteristics and results of surgical treatment. Breast J. 2005.
Common Exam Questions
- Aetiology: "Strongest risk factor for recurrent subareolar abscess?"
- Answer: Smoking.
- Pathology: "Histological change in ducts?"
- Answer: Squamous Metaplasia.
- Microbiology: "Organisms involved?"
- Answer: Mixed Anaerobes (Bacteroides) + Staph.
- Surgery: "Name of definitive procedure?"
- Answer: Total Duct Excision (Hadfield's).
Viva Points
- Differentiating from Duct Ectasia: PDM is young smokers with inflammation. Duct Ectasia is older women with involution/slit-like retraction and usually minimal inflammation.
- Why Co-Amoxiclav?: Flucloxacillin alone (standard for lactational mastitis) will fail because it does not cover the anaerobes found in PDM.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.