Breast Cellulitis

Breast cellulitis is a spreading bacterial infection of the skin and subcutaneous tissue of the breast without a collection of pus. Streptococci and Staphylococcus aureus are the usual causes, entering through nipple cracks, surgical wounds, insect bites, piercings or skin conditions. It occurs in breastfeeding women, after breast surgery or radiotherapy, and in women with lymphoedema or diabetes. It matters because it can progress to abscess and sepsis, and it can be mistaken for inflammatory breast cancer.

• Risk factors: breast surgery or reconstruction, radiotherapy, lymphoedema, diabetes, obesity, skin conditions (eczema), nipple cracks, shaving, piercings, large pendulous breasts with skin folds (intertrigo).
• Rapid spread over hours with fever and malaise.
• Failure to settle in 7 days needs biopsy.

Women have a red, hot, tender, swollen area of breast skin with ill-defined edges, with fever, chills and malaise. The skin may be shiny, blistered or have lymphangitis streaks toward the axilla.

• Diffuse redness with warmth and tenderness, without a fluctuant mass.
• Tender axillary lymph nodes.
• Differential diagnosis: mastitis, breast abscess, inflammatory breast cancer, contact dermatitis, herpes zoster, erysipelas, radiation dermatitis, lymphoedema, necrotising fasciitis, tuberculous mastitis.
• Complications: abscess, sepsis, necrotising infection, recurrent cellulitis, lymphoedema, scarring, delay in diagnosis of cancer.

The diagnosis is clinical, with tests to find a collection and to exclude cancer when the response is poor.

• Examination of the breast, skin, nipples and axillae; mark the edge of the redness with a pen; temperature, pulse, blood pressure.
• Ultrasound to exclude abscess; full blood count, C-reactive protein, glucose; blood culture if febrile; swab of any wound or discharge.
• Skin punch or core biopsy if there is no improvement by 7 days or peau d'orange appears.
• Mammography if age is 40 years or above and the infection has settled.

The principle is early antibiotics against streptococci and staphylococci, with review for abscess and biopsy if there is no response.

• Supportive: mark and review the border of redness; elevate and support the breast; rest; fluids; paracetamol; cold or warm compress for comfort; skin care and treatment of fungal skin folds; control glucose; continue breastfeeding if lactating and the wound is away from the nipple.
• Pharmacological: flucloxacillin 500 mg to 1 g oral 6-hourly for 7 days (1 to 2 g IV 6-hourly if systemically unwell, then oral when afebrile for 24 hours); cefalexin 500 mg oral 6-hourly for 7 days as an alternative; penicillin allergy: clindamycin 300 to 450 mg oral every 6 to 8 hours for 7 days; methicillin-resistant Staphylococcus aureus: co-trimoxazole 960 mg oral 12-hourly for 7 days (not in the first month of life for the breastfed infant) or vancomycin 15 mg/kg IV 12-hourly for severe infection; 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; recurrent cellulitis: phenoxymethylpenicillin 250 mg oral twice daily for 6 to 12 months.
• Procedures: drainage if an abscess forms; biopsy of skin and breast tissue if no response by 7 days; surgical debridement for necrotising infection.
• Special groups: women with diabetes have insulin to keep glucose below 10 mmol/L and a 10 day course; women with lymphoedema after breast surgery have compression care and prophylaxis against recurrence with phenoxymethylpenicillin 250 mg oral twice daily; breastfeeding women continue feeding during treatment, preferring flucloxacillin or cefalexin, and the infant's stool is checked for diarrhoea.
• Red flags: rapid spread, blistering or dusky skin, severe pain out of proportion, crepitus, hypotension, fever above 39 degrees Celsius, no improvement by 48 hours, fixed hard mass or peau d'orange.
• Follow-up: review at 48 hours with the marked border; review at 1 week; ultrasound for persistent swelling; mammography and examination at 4 to 6 weeks; plan for recurrent cellulitis.