Skin Exam Findings of Frostbite on Feet
Frostbite on the feet presents with distinct skin findings that vary by severity, including numbness, pale or white skin appearance, firm but pliable skin texture in early stages, progressing to hard waxy appearance, complete sensation loss, dark discoloration, and blister formation after rewarming. 1
Characteristic Skin Findings by Severity
Early/Superficial Frostbite
- Numbness of the affected area
- Pale or white skin appearance
- Firm skin texture that remains pliable
- Tingling and pain (particularly during rewarming)
- Clear fluid-filled blisters that develop after rewarming (indicating less severe injury) 1
Severe/Deep Frostbite
- Hard, waxy appearance of skin
- Complete loss of sensation in affected area
- Dark discoloration (blue, gray, or black)
- Blood-filled blisters after rewarming (indicating more severe injury)
- Without proper treatment, progression to tissue mummification and dry gangrene 1
Key Assessment Points
- Examine between toes carefully, as these areas are commonly affected
- Assess for concurrent hypothermia, which frequently accompanies frostbite 1
- Note that frozen tissue is numb, so patients may be unaware of ongoing mechanical damage 1, 2
- After rewarming, hyperemia (increased blood flow) occurs and is often painful 2
- Edema typically develops following rewarming 2
- Hard eschar may form with healthy tissue deep beneath it 2
Diagnostic Considerations
- Initial appearance may not accurately predict the final extent of tissue damage
- The true demarcation line between viable and non-viable tissue often takes days to weeks to become apparent 3
- In severe cases, bone scintigraphy may be used to predict amputation risk, with absence of uptake in the bone phase indicating poor prognosis 4
Clinical Pitfalls to Avoid
- Avoid premature prediction of tissue loss based on initial appearance
- Do not debride blisters as they provide natural protection 1
- Recognize that the presence of blood-filled blisters indicates more severe injury than clear fluid-filled blisters 1
- Be aware that repeated freeze-thaw cycles dramatically worsen tissue damage 1
- Remember that frozen tissue has decreased sensation, making patients vulnerable to burn injuries during rewarming 1
Early recognition of frostbite severity through careful skin examination is crucial for determining appropriate treatment strategies and reducing the risk of amputation, particularly in severe cases where interventions like iloprost therapy may be beneficial 4, 5.