II. Definitions

  1. Frostbite
    1. Skin (and deeper structures) freeze resulting in tissue injury
  2. Frostnip
    1. Superficial ice crystals deposit on the skin surface without tissue injury

III. Risk Factors

  1. Peripheral Vascular Disease
  2. Peripheral Neuropathy (e.g. Diabetic Neuropathy)
  3. Prolonged cold or moisture exposure
  4. High wind (high wind chill)
  5. High altitude
  6. Inadequate clothing
  7. Malnutrition
  8. Extremes of age
  9. Vasoconstrictive agents (e.g. nicotine)
  10. Altered Mental Status

IV. Pathophysiology: Changes by skin Temperature

  1. Room Temperature
    1. Normal skin perfusion >200 ml/min
  2. Skin Temperature 59 F (15 C)
    1. Skin perfusion 20-50 ml/min
    2. Vasoconstriction interrupted by periods of vasodilation lasting 5-10 minutes each, recurring every 15-20 minutes
  3. Skin Temperature 50 F (10 C)
    1. Skin sensation lost (Neuropraxia)
  4. Skin Temperature 32 F (0 C)
    1. Minimal skin perfusion
    2. Skin Temperature drops each minute by 0.9 F (0.5 C)
  5. Skin Temperature <31.1 F (-0.5 C)
    1. Intra and extracellular water crystals form, disrupting membranes and protein structures
    2. Osmotic gradient and electrolyte shifts occur and ultimately lead to cell death
    3. Vascular stasis and ultimately tissue ischemia and necrosis

V. Pathophysiology: Stages of Frostbite

  1. Pre-freeze
    1. Superficial tissues are cooled
  2. Freeze-thaw
    1. Intra and extracellular water crystals form, disrupting membranes and protein structures and cell death
    2. Thawing may lead to inflammatory response and reperfusion injury
  3. Vascular stasis
    1. Vasoconstriction alternates with vasodilation resulting in vessel leaks and intravascular coagulation
  4. Tissue ischemia and necrosis
    1. Intravascular thrombosis with secondary tissue ischemia and infarction

VI. Signs: Classification - 4 category (similar to Burn Injury classification)

  1. Precautions
    1. Classification should only be applied after rewarming is complete
    2. Accurate classification may be delayed for first 1-3 months
  2. First-degree Frostbite (superficial skin)
    1. Numb, erythematous skin
    2. May develop yellow-white Plaques
    3. Tissue may slough
  3. Second-degree Frostbite (full skin thickness)
    1. Clear to milky fluid-filled bullae
    2. Surrounding edema and erythema forms in the first 24 hours after injury
  4. Third-degree Frostbite (full skin thickness AND subcutaneous tissue involvement)
    1. Hemorrhagic bullae
  5. Fourth-degree Frostbite (full skin thickness AND muscle/bone involvement)
    1. Mottled, deep red or cyanotic skin
    2. Bone and muscle freezing
    3. Dry , black mummified skin

VII. Signs: Classification - 2 category (preferred in the acute setting)

  1. Distribution - high risk areas
    1. Extremities (hands, feet)
    2. Face (ears, nose)
    3. Genitalia (penis)
  2. Superficial Frostbite (includes first and second degree Frostbite as above)
    1. Erythema and edema
    2. Minimal to no tissue loss
    3. No hemorrhagic bullae (but clear or milky bullae may be present)
  3. Deep Frostbite (includes third and fourth degree Frostbite as above)
    1. Woody-feel to skin
    2. Hemorrhagic bullae
    3. Tissue loss (including bone and muscle injury)
    4. Mummification or amputation

VIII. Management: Acute

  1. Precautions
    1. Do not rewarm if chance of refreezing (risk of inflammation, thrombosis, cell death)
    2. Do not rub or massage skin
    3. Clear any evaporative liquids (e.g. gas, Alcohol)
    4. Avoid external dry heat (e.g. fire, radiator)
  2. Initial measures
    1. Remove all jewelry and wet clothing
    2. Rapid rewarming in warm (40-42 C, 104-107.6 F) water bath for 15-30 min
      1. Continue until skin is pliable, soft, red or purple
    3. Elevate involved area (decrease edema)
    4. Protect the injured limb with padding
    5. Opioid Analgesics and or NSAIDS (esp. for rewarming)
    6. Topical aloe vera applied to thawed tissue every 6 hours
    7. Tetanus prophylaxis
    8. Consider aspirating clear-milky bullae
      1. Do not aspirate or debride hemorrhagic tissue (may dessicate deeper tissue injury)
    9. Daily Hydrotherapy (30 to 45 minutes at 40 C, 104 F) improves range of motion and function
  3. Other measures (discuss with local consultants)
    1. Tissue plasminogen activator (tPA)
      1. Has been used for deep Frostbite within first 24 hours to reduce risk of amputation
      2. Ibrahim (2015) J Burn Care Res 36(2): e62-6 [PubMed]
    2. Hyperbaric oxygen

IX. Management: Longterm

  1. Refer deeper Frostbite to wound care or burn specialist
  2. Indications for transfer or referral to higher level of care (e.g. burn center)
    1. Deep Frostbite
    2. Extensive limb involvement
    3. Concerns for Compartment Syndrome (if unable to manage locally)
  3. Surgical Management
    1. Delay surgical amputation or debridement for 1-3 months until demarcation of mummified areas
    2. Earlier debridement may be needed if refractory superinfection occurs

X. Complications

  1. Compartment Syndrome
  2. Excessive sweating
  3. Cool extremities
  4. Numbness
  5. Abnormal color
  6. Nail Disorder
  7. Skin Pigment Changes
  8. More susceptible to second injury
  9. Limb Amputations (4th degree, mummified tissue)

XI. Prevention

  1. Never ignore numbness in a cold extremity

XII. Images

  1. Presentation Graphic
    1. erEnvironFrostbite.jpg

XIV. References

  1. Civitarese and Sciano (2018) Crit Dec Emerg Med 32(2): 3-16

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Ontology: Frostbite (C0016736)

Definition (MEDLINEPLUS)

Frostbite is an injury to the body that is caused by freezing. It most often affects the nose, ears, cheeks, chin, fingers, or toes. Frostbite can permanently damage the body, and severe cases can lead to amputation.

Signs of frostbite include

  • A white or grayish-yellow skin area
  • Skin that feels unusually firm or waxy
  • Numbness

If you have symptoms of frostbite, seek medical care. But if immediate medical care isn't available, here are steps to take:

  • Get into a warm room as soon as possible.
  • Unless absolutely necessary, do not walk on frostbitten feet or toes. Walking increases the damage.
  • Put the affected area in warm - not hot - water.
  • You can also warm the affected area using body heat. For example, use your armpit to warm frostbitten fingers.
  • Don't rub the frostbitten area with snow or massage it at all. This can cause more damage.
  • Don't use a heating pad, heat lamp, or the heat of a stove, fireplace, or radiator for warming. Since frostbite makes an area numb, you could burn it.

Centers for Disease Control and Prevention

Definition (NCI) Damage to tissues as the result of low environmental temperatures. (MeSH)
Definition (MSH) Damage to tissues as the result of low environmental temperatures.
Concepts Injury or Poisoning (T037)
MSH D005627
ICD10 T33-T35.9 , T33-T34
SnomedCT 157717008, 213637003, 370977006, 38045000
English Frostbites, Frostbite, frostbite (diagnosis), frostbite, Frostbite [Disease/Finding], frostbites, Frostbite (T33-T34), Frostbite (event), Congelation injury, Frostbite (disorder), Frostbite - disorder, Congelation injury, NOS, Frostbite, NOS
Japanese 凍傷, トウショウ
Swedish Frostskada
Czech omrzlina, Omrzlina
Finnish Paleltumavamma
Polish Odmrożenie
Hungarian Fagyás
Norwegian Frostskader, Kuldeskader, Forfrysninger
Portuguese Ulceração por Frio, Queimadura por Frio, Congelação, Congelamento das Extremidades
Spanish congelamiento (trastorno), congelamiento, Congelación, Congelación de Extremidades
Dutch bevriezing, Bevriezing
French Gelure, Gelures
German Erfrierung
Italian Congelamento

Ontology: Frost nip (C0344186)

Concepts Injury or Poisoning (T037)
SnomedCT 241966002, 112632004
English frost nip, frostnip, frostnips, Frost nip, Frostnip, Frost nip (disorder)
Spanish escarchado (trastorno), escarchado