Which of the following is a hallmark sign differentiating heat stroke from other heat illnesses?

• A. Hot, dry skin
• B. Profuse sweating
• C. Numbness
• D. Excess saliva

Answer: (A)

Heat stroke occurs when the body's ability to regulate temperature breaks down, causing a rapid and dangerous rise in core temperature. A defining sign is hot, dry skin, because sweating has stopped or greatly diminished. This dryness signals that the cooling mechanism is failing, which is what differentiates heat stroke from other heat illnesses, where sweating persists. For example, heat exhaustion typically presents with sweating and moist skin along with fatigue and dizziness. Numbness or excessive saliva aren’t characteristic features of heat stroke. When you see someone with hot, dry skin and altered mental status or other danger signs, it’s a medical emergency—seek help immediately and begin rapid cooling.