From pustule to flap: necrotizing fasciitis of the breast in type 1 diabetes-a case report.

Necrotizing soft tissue infections of the breast are exceptionally rare surgical emergencies with high mortality, and monomicrobial Escherichia coli (Type 3) necrotizing fasciitis is an uncommon, highly virulent form. We report a 23-year-old woman with insulin-treated Type 1 diabetes mellitus as her only comorbidity who developed extensive breast necrosis from a small pustule and presented with sepsis. Wound cultures were sterile while blood cultures grew E. coli. She underwent repeated debridement, sequential vacuum-assisted closure therapy and, after infection control, latissimus dorsi myocutaneous flap reconstruction, followed by revision for partial lateral flap necrosis, and was discharged in good condition. Even a minor skin breach in a diabetic patient may trigger fulminant gram-negative necrotizing fasciitis; early recognition, aggressive debridement, culture-guided antibiotherapy, vacuum-assisted closure, and staged flap reconstruction are critical for survival and functional recovery.