Periductal Mastitis

Periductal mastitis is inflammation around the large subareolar milk ducts, usually from dilatation and blockage of the ducts followed by infection with mixed skin and anaerobic bacteria. It occurs in non lactating women aged 30 to 50 years, and is strongly linked to smoking. It matters because it leads to recurrent abscess and fistula, and it must be separated from breast cancer.

• Risk factors: smoking (the main cause), nipple retraction, nipple piercing, diabetes, obesity, previous episode, duct ectasia.
• Common anaerobic organisms need coverage in treatment.
• Recurrence is frequent unless smoking stops.

Women have periareolar pain, redness and swelling, nipple retraction, nipple discharge (green, brown or purulent), a tender subareolar lump, and sometimes fever. Chronic disease causes an abscess and a fistula opening at the edge of the areola.

• Periareolar redness, tenderness and thickened ducts.
• Nipple inversion that is new and slit shaped.
• Differential diagnosis: lactational mastitis, mammary duct ectasia, intraductal papilloma, Paget disease of the nipple, breast cancer, granulomatous mastitis, tuberculosis, subareolar abscess, nipple eczema.
• Complications: subareolar abscess, mammary duct fistula, recurrent infection, nipple deformity, chronic pain, scarring.

The approach is examination with imaging and biopsy to exclude cancer.

• Examination of nipples, areolae, breasts and axillae; note discharge, retraction, mass and fistula.
• Breast ultrasound (dilated subareolar ducts, abscess); mammography if age is 40 years or above.
• Culture of discharge or pus (aerobic and anaerobic); cytology of nipple discharge; core biopsy of a mass that persists.
• Full blood count, C-reactive protein, glucose.

The principle is antibiotics for acute infection, drainage of abscess, and duct excision for recurrent or persistent disease, together with stopping smoking.

• Supportive: stop smoking (the most important step); warm compress; supportive bra; analgesia; remove nipple jewellery; good nipple hygiene; control diabetes.
• Pharmacological: amoxicillin-clavulanate 625 mg oral 8-hourly for 7 to 10 days; or cefalexin 500 mg oral 6-hourly plus metronidazole 400 mg oral 8-hourly for 7 to 10 days; penicillin allergy: clindamycin 300 mg oral 6-hourly plus ciprofloxacin 500 mg oral 12-hourly for 7 to 10 days; severe infection: ceftriaxone 2 g IV once daily plus metronidazole 500 mg IV 8-hourly until improved, then oral therapy to complete 10 to 14 days; paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours); ibuprofen 400 mg oral 8-hourly with food for 3 to 5 days.
• Procedures: ultrasound guided aspiration of abscess under lignocaine 1 percent (maximum 3 mg/kg, not above 200 mg), repeated every 1 to 3 days; incision and drainage for large abscess; total duct excision (microdochectomy) with excision of any fistula, done after the acute infection has settled, for recurrent disease; nipple eversion procedures after healing.
• Special groups: women with diabetes need insulin to keep glucose below 10 mmol/L and a full 14 day course; women who continue to smoke are counselled on recurrence and given support to stop.
• Red flags: persistent mass beyond 2 weeks of treatment, hard fixed mass, bloody nipple discharge, skin thickening, spreading cellulitis, fever with systemic upset, recurrent abscess.
• Follow-up: review at 1 week and 4 weeks; ultrasound at 4 weeks; surgical review after 2 episodes; breast examination at 3 months and mammography as indicated by age.