BREAST
UKMLA Conditions Categorised by Body System
, Breast Abscess / Mastitis
Inflammation of breast tissue, with or without infection. Most commonly occurs as lactational mastitis in breastfeeding
women; a breast abscess is a localised collection of pus that can develop if mastitis is untreated or does not resolve.
Key clinical features
• Lactational mastitis: unilateral breast pain, redness (often wedge-shaped), warmth and swelling; flu-like symptoms
(fever, myalgia); typically 2–3 weeks postpartum; often associated with a cracked nipple or blocked duct.
• Non-lactational mastitis: more common in smokers; periareolar pain/redness, often linked to duct ectasia or periductal
mastitis; may cause nipple inversion or a subareolar mass.
• Breast abscess: a localised, tender, fluctuant mass with overlying erythema, plus systemic signs of infection (fever,
malaise). Overlying skin necrosis can occur if severe.
Figure 1: Breast anatomy and typical site of abscess formation within the glandular tissue.
Investigations
• Usually a clinical diagnosis — investigations are for atypical, non-resolving or recurrent cases.
• Breast milk culture and sensitivity if lactational mastitis fails to respond to first-line antibiotics.
• Breast ultrasound to distinguish a discrete abscess (fluctuant collection) from diffuse mastitis, and to guide aspiration.
• Swab of any nipple discharge for microbiology (Staphylococcus aureus is the most common organism).
• Mammography ± biopsy if non-lactational, recurrent, or not responding to treatment — to exclude inflammatory breast
cancer.
Treatment and management
• Continue breastfeeding or expressing milk — effective milk removal is the cornerstone of managing lactational mastitis.
• Analgesia: paracetamol and/or NSAIDs.
• Antibiotics if systemic upset, a visible fissure, or no improvement within 12–24 hours of conservative measures:
flucloxacillin first-line (co-amoxiclav or clindamycin/erythromycin if penicillin-allergic).
• Confirmed abscess: ultrasound-guided needle aspiration is first-line (may need repeating); incision and drainage is
reserved for large or multiloculated abscesses, or where aspiration fails.
• Non-lactational/recurrent disease: smoking cessation advice; surgical excision of the affected duct may be needed for
recurrent periductal mastitis with fistula.
Complications
• Abscess formation and need for repeated drainage
• Sepsis
• Milk fistula
• Scarring or chronic recurrent infection
• Reduced milk supply / early cessation of breastfeeding if untreated
• Red flag: inflammatory breast cancer can mimic mastitis — suspect this if there is no response to antibiotics, prompting
urgent imaging and biopsy.
UKMLA Conditions Categorised by Body System
, Breast Abscess / Mastitis
Inflammation of breast tissue, with or without infection. Most commonly occurs as lactational mastitis in breastfeeding
women; a breast abscess is a localised collection of pus that can develop if mastitis is untreated or does not resolve.
Key clinical features
• Lactational mastitis: unilateral breast pain, redness (often wedge-shaped), warmth and swelling; flu-like symptoms
(fever, myalgia); typically 2–3 weeks postpartum; often associated with a cracked nipple or blocked duct.
• Non-lactational mastitis: more common in smokers; periareolar pain/redness, often linked to duct ectasia or periductal
mastitis; may cause nipple inversion or a subareolar mass.
• Breast abscess: a localised, tender, fluctuant mass with overlying erythema, plus systemic signs of infection (fever,
malaise). Overlying skin necrosis can occur if severe.
Figure 1: Breast anatomy and typical site of abscess formation within the glandular tissue.
Investigations
• Usually a clinical diagnosis — investigations are for atypical, non-resolving or recurrent cases.
• Breast milk culture and sensitivity if lactational mastitis fails to respond to first-line antibiotics.
• Breast ultrasound to distinguish a discrete abscess (fluctuant collection) from diffuse mastitis, and to guide aspiration.
• Swab of any nipple discharge for microbiology (Staphylococcus aureus is the most common organism).
• Mammography ± biopsy if non-lactational, recurrent, or not responding to treatment — to exclude inflammatory breast
cancer.
Treatment and management
• Continue breastfeeding or expressing milk — effective milk removal is the cornerstone of managing lactational mastitis.
• Analgesia: paracetamol and/or NSAIDs.
• Antibiotics if systemic upset, a visible fissure, or no improvement within 12–24 hours of conservative measures:
flucloxacillin first-line (co-amoxiclav or clindamycin/erythromycin if penicillin-allergic).
• Confirmed abscess: ultrasound-guided needle aspiration is first-line (may need repeating); incision and drainage is
reserved for large or multiloculated abscesses, or where aspiration fails.
• Non-lactational/recurrent disease: smoking cessation advice; surgical excision of the affected duct may be needed for
recurrent periductal mastitis with fistula.
Complications
• Abscess formation and need for repeated drainage
• Sepsis
• Milk fistula
• Scarring or chronic recurrent infection
• Reduced milk supply / early cessation of breastfeeding if untreated
• Red flag: inflammatory breast cancer can mimic mastitis — suspect this if there is no response to antibiotics, prompting
urgent imaging and biopsy.
