Juan has been working in the hot sun all day. He begins acting delirious with an extremely hot temperature and dry, red skin. What might he be suffering from?

The symptoms described indicate that Juan is likely suffering from heat stroke. Heat stroke occurs when the body becomes unable to regulate its temperature, leading to a rapid rise in core body temperature—often reaching above 104°F (40°C). This condition is characterized by confusion or delirium, high body temperature, and dry, red skin due to a failure of the body's thermoregulation mechanisms, including the loss of sweat.

In contrast, heat rash would typically present with skin irritation rather than severe systemic symptoms like delirium. Heat cramps involve muscle spasms and do not cause the confusion or high body temperature observed in Juan's case. Heat exhaustion is marked by symptoms such as heavy sweating, weakness, and an elevated heart rate, but it does not typically progress to the life-threatening state of confusion or unconsciousness associated with heat stroke. Given these considerations, the signs of serious heat-related illness point clearly to heat stroke as the most severe condition affecting Juan.