Wounds that arise during an intensive care unit (ICU) admission, pose a notable challenge, exacerbated by the difficulty of ascertaining accurate medical history from critically unwell individuals. This study examines a unique case within this milieu, highlighting the complexities of assessing, diagnosing and managing injuries amidst the complexities of critical illness. This study brings light to an aetiology that was initially overlooked when an evolving, blistering rash in a 70-year-old was initially referred for with necrotizing fasciitis. We report a case in which a 70-year-old patient sustained an out of hospital cardiac arrest secondary to asthma and tension pneumothorax. On day 10 during his ICU admission, the patient was referred to the plastic surgery team for evaluation of a new, evolving, blistering rash to the right dorsal wrist initially suspected to be necrotising fasciitis by the intensivists. Debridement was undertaken at which time it became clear that this was a localised non-infectious soft tissue injury of unclear aetiology. Further investigation revealed that this was likely due to extravasation from a calcium chloride infusion used in the ICU for cardiac stabilisation. Early recognition and accurate diagnosis of uncommon presentations such as extravasation injuries are crucial for appropriate management and prevention of further complications. Collaboration between specialties is imperative for optimal patient care and outcomes.