A red and warm abdomen. What’s the matter?

An 83-year-old woman presented to our emergency department for a fever with nausea and an itching skin rash on her abdomen for two days. She suffered from obesity, Parkinson disease, and depression in treatment with Levodopa/Benserazide and Pramipexole, respectively. She underwent mastectomy for left breast cancer ten years earlier. She denied any allergies or use of antibiotics. Her vital signs were blood pressure 120/65 mmHg, heart rate 72 bpm, peripheral oxygen saturation 94% in room air, respiratory rate 18/min, and body temperature 36.2 °C. Examination of her abdomen revealed an extensive red warm rash without blisters or blebs, with a slight skin oedema confirmed by point-of-care ultrasound, that excluded a subcutaneous abscess, pneumoniae, liver and kidney damage, and cholecystitis. Laboratory findings showed WBC 12,400/mm³ (N 59.5%) and CRP 131 mg/L (n.v. < 5). Procalcitonin was 0.3 ng/mL (n.v. < 0.5). SARS-CoV-2 infection was excluded.