Which symptom indicates a potential need for antivenom in a patient?

The indication for antivenom administration in a patient who has been envenomated typically arises from the presence of severe systemic symptoms. These symptoms may include widespread effects that can disrupt normal physiological functions, such as significant respiratory distress, cardiovascular instability, or altered mental status. Such systemic involvement signifies that the venom is affecting the body beyond the site of the bite or sting and requires more aggressive intervention to mitigate potential life-threatening complications.

In contrast, symptoms like a minor rash or localized swelling may not necessitate antivenom. These are often signs of mild reactions or localized effects that could resolve with standard care. While a rapid heartbeat can be concerning, it may be a compensatory response to pain or anxiety rather than a direct indication for antivenom use. Therefore, the presence of severe systemic symptoms is the key factor that highlights the urgent need for antivenom therapy.