Abdominal Wall Erythema as a Suspected Extracardiac Manifestation of Cardiac Allograft Rejection

In a heart transplant recipient, a new cutaneous finding can be difficult to attribute to a single cause, and the clinical context does not always point to localized skin disease. We describe the case of a 54-year-old man five years after orthotopic heart transplantation who presented with severe periumbilical pain, hypoxemia, and abdominal wall erythema one week after completing intravenous immunoglobulin and rituximab for biopsy-proven antibody-mediated rejection (AMR). Computed tomography suggested paraumbilical cellulitis and possible pulmonary infection, and empiric antibiotics were appropriately initiated. However, the erythema was non-purulent and non-necrotizing, blood cultures were negative, there was no clear bacterial skin source, the patient's atypical pretransplant ischemic pain phenotype had recurred, and the tacrolimus trough was subtherapeutic at 3.4 ng/mL, together raising concern for ongoing allograft immune injury. This case supports treating apparent cellulitis while urgently considering an extracardiac manifestation of graft rejection when support for a localized infectious source is weak and the transplant context is high risk. Preserved left ventricular ejection fraction does not exclude recurrent AMR or cardiac allograft vasculopathy, and early transplant-center coordination remains the critical management step.