Frostbite Basics: 

-Have high suspicion for injury when temperature drops below -20C (-4F) * risk correlates with temperature *
-Not all frostbite from environmental exposure:
     -Prolonged contact with ice packs, contact with frozen metal surfaces, inhalation of hydrocarbons (ex: Freon)
-High Risk Groups: outdoor workers, homeless, elderly, drug/alcohol users, psychiatric disease
- Most common areas affected: fingers, toes, nose, ear

• Classification:
  - 1st degree (frostnip) - erythematous skin, no blisters; pain/numbness
  - 2nd degree - erythematous skin, blisters filled with clear fluid; +/- pain, numbness (**See example below**)
  - 3rd degree - blue/grey discoloration of skin, hemorrhagic blisters; numbness with “block of wood” sensation
  - 4th degree - non blanching cyanosis, dry/black eschar; numbness with “block of wood” sensation

• Clinical diagnosis:
  - Often no need for labs/imaging
• Treatment:
  - Rapid rewarming in circulating water heated to 37-39C
  - Anticipate severe pain during rewarming, treat appropriately (often require opioids)
  - Debride broken vesicles, cover with topical antibiotics
  - Update tetanus (frostbite is tetanus prone wound)
  - Surgical consult for severe injuries as may require multiple tissue debridements/escharotomy/fasciotomy/amputation

Resource:
Stapczynski, J. Stephan,, and Judith E. Tintinalli. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York, N.Y.: McGraw-Hill Education LLC., 2011