Which symptom is a hallmark sign of heat stroke?

• A. Chills
• B. Dizziness
• C. Nausea
• D. Hot, dry skin

Answer: (D)

Heat stroke happens when the body's cooling system stops working and sweating stops, so the skin becomes hot and dry. That dry, overheated skin is the most telling sign because it directly shows thermoregulation has failed and core temperature is rising rapidly. This sets heat stroke apart from heat exhaustion, where the skin is usually sweaty and moist. While dizziness or nausea can occur with heat illness, they are not the defining clue; hot, dry skin specifically points to heat stroke and signals an urgent need for emergency care and rapid cooling.