St. John Ambulance First Aid Practice Exam 2025 - Free First Aid Practice Questions and Study Guide

Deep frostbite is associated with the highest risk of permanent damage. This type of frostbite affects not only the skin but also deeper tissues, including muscles, blood vessels, and nerves. When tissue freezes, ice crystals can form within cells, which leads to cell damage and eventual cell death. This can result in severe complications such as loss of limbs, loss of function in affected areas, and potentially infection.

In cases of deep frostbite, there is often significant tissue damage that may necessitate medical intervention such as surgical removal of dead tissue (debridement) or even amputation in severe cases. The potential for permanent damage is a critical concern, as recovery can take a long time, and affected individuals may experience chronic pain, sensitivity to cold, and various other impairments.

In contrast, superficial frostbite primarily impacts the outer layers of the skin and is less likely to cause permanent damage if treated promptly. Moderate and advanced classifications generally fall somewhere in between, but deep frostbite remains the most severe with the greatest risk for lasting injury.