Which condition primarily causes frostbite?

Frostbite occurs primarily due to exposure to freezing temperatures, which leads to skin and tissue damage. When the body is exposed to extremely cold conditions, especially combined with wind, the risk of frostbite increases significantly. The cold causes blood vessels near the surface of the skin to constrict in order to conserve heat, which can ultimately restrict blood flow. If the skin temperature drops low enough, ice crystals can form in the cells, leading to cellular injury and potential tissue death.

In contrast, excessive heat and direct sunlight are associated with heat-related conditions such as heat exhaustion or heat stroke. High humidity levels can exacerbate heat-related illnesses but do not contribute to frostbite. Thus, consistent exposure to freezing temperatures is the primary factor responsible for this condition.