In the case of acute organ rejection, which of the following symptoms are typically observed?

Acute organ rejection often presents with flu-like symptoms, which can include fever, malaise, and general feelings of unwellness. These systemic signs often occur as the immune system responds to recognize the transplanted organ as foreign, leading to an inflammatory response. The patient's body may react similarly to how it would with an infection, which is why these flu-like symptoms can arise.

The other symptoms listed may not be as commonly associated with acute organ rejection. For example, nausea and vomiting may occur in various medical conditions, including post-operative experiences or other complications, but they are not specific indicators of acute rejection. Similarly, acute abdominal pain is typically more indicative of intra-abdominal issues rather than direct signs of organ rejection. Rash and urticaria, while seen in some rejection scenarios, tend to be more associated with allergic reactions or skin-related processes, and are not classic signs of acute rejection in most organ transplant cases. Thus, flu-like symptoms are the most recognizable and typical markers of acute organ rejection.