What condition typically indicates the onset of frostbite?

The onset of frostbite is typically indicated by a burning pain and numbness in the affected areas. As the skin and underlying tissues begin to freeze due to prolonged exposure to cold temperatures, nerve endings react, causing an initial sensation of burning or tingling. This is often followed by numbness as the tissue continues to freeze and blood flow decreases. Recognizing this early symptom is crucial for prompt intervention, as it can help prevent further tissue damage.

While localized swelling, excessive reddening of the skin, and a dull ache in joints may present in other conditions or later stages of frostbite, they are not the primary indicators of its onset. The burning pain and subsequent numbness are the earliest signs and serve as a warning that immediate action should be taken to protect the affected area from further cold exposure or injury.