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Other Names

  • Frostbite
  • Frostnip


  • This page refers to Frostbite, a freezing cold thermal injury that occurs when tissues are exposed to temperatures below their freezing point
    • Frostnip is a reversible cold injury that can progress to frostbite


  • The first physical evidence of frostbite injury is in a 5000-year-old pre-Columbian mummy discovered in the Andes[1]
  • Well documented history of afflicting armies including
    • Hannibal crossing the Alps in 218 BC, when only 19,000 survived out of 38,000
    • American war for Independence where cold causality rates were described as high as 10%[2]
    • Napoleon Bonaparte’s Surgeon in Chief, Dominique Jean Larrey, wrote the first authoritative report on frostbite and cold injury[3]


  • Incidence
    • Among mountaineers, one study found a mean incidence of 366 per 1000 population per year[4]
    • The incidence for cold injury of 65.6 per 1000 per year in the British Antarctic Survey; 95%of this was for frostbite[5]
    • At the Mount Everest Emergency Room, cold exposure accounts for 18.4% of visits, of which 83.7% are attributable to frostbite[6]


Grade 2 frostbite at 24 hours (A), Grade 2 right hand, grade 3 left hand at 36 hours (B), Grade 2 right hand and grade 3 left at 36 hours following iodine treatment (C), grade 2 right hand and grade 3 left hand at 5 days (D), grade 3 at 3 months, note mummification (E), grade 3 at 4 months (F)[7]
  • General
    • Definition: cold thermal injury which occurs when tissues are exposed to temperatures below their freezing point
    • Can result in debilitating long-term irreversible morbidity.
    • Prevention is the key in preventing morbidity
  • Risk correlated with temperature and wind speed
    • Risk is <5% when ambient temperature (includes wind chill) is > –15°C (5°F)
    • Most often occurs at ambient temperature < –20°C (–4°F)


  • Direct cellular injury and death occurs due to a variety of mechanisms including:[8]
    • Ice crystal formation (intracellular and extracellular)
    • Cell dehydration and shrinkage
    • Electrolyte disturbances
    • Denaturation of lipid-protein complexes,
    • Thermal shock
  • Indirect cellular injury (progressive dermal ischemia)
    • Occurs secondary to progressive microvascular insult; more severe than the direct cellular effect
    • Following thawing, microvascular thrombosis occurs, resulting in continued cell injury and death
    • The following play a role in the progressive ischemia: endothelial damage, intravascular sludging, increased levels of inflammatory mediators and free radicals, reperfusion injury, and thrombosis


  • Zone of Coagulation
    • Most severe and usually most distal
    • Damage is irreversible
  • Zone of Stasis
    • Middle zone characterized by severe, but possibly reversible, cell damage
    • It is this zone for which treatment may have benefit
  • Zone of Hyperemia
    • Least severe and usually most proximal
    • Generally recovers without treatment in <10 d

Risk Factors

Wind Chill Chart[9]
  • Sports
    • Mountaineering
  • Occupational
    • Working with equipment that uses NO2 or CO[10]
  • Behavioral/ Socioeconomic[11]
    • Alcohol consumption
    • Tobacco Use
    • Vagrancy
    • Unplanned exposure to cold with inadequate protection
    • Previous cold injury
  • Medical
    • Psychiatric illness
    • Several medications (eg, b-blockers)

Differential Diagnosis

Clinical Features

  • History
    • Early recognition is key
    • Paresthesias may be the first symptom
    • Patients will also report feeling cold, numb and/or clumsy
  • Physical Exam
    • Appearance is variable and can be misleading
    • Color may be yellow-white or mottled blue
    • The affected area is insensate and often obviously frozen
    • Edema and blistering does not occur until after rewarming
  • Special Tests


  • Imaging and laboratory evaluation not needed to make diagnosis
    • Useful if other pathology is considered


Visual determination of tissue viability is difficult in first few weeks; classify early injuries as superficial or deep

Degree First (frostnip) Second Third Fourth
Pathophys Partial-skin freezing Full-thickness skin freezing Tissue loss involving entire thickness of skin Extension into subcutaneous tissues, muscle, bone, and tendon; little edema
Symptoms Stinging and burning, followed by throbbing Numbness followed by aching and throbbing Extremity feels like a "block of wood" followed by burning, throbbing, shooting pains Deep, aching joint pain
Course Numbness, erythema, swelling, dysesthesia, desquamation (days later)

Substantial edema over 4-6 hours; skin blisters form within 6-24 hours; Desquamate and form hard black eschars over several days

Hemorrhagic blisters form and are associated with skin necrosis and blue-gray discoloration Skin is mottled with nonblanching cyanosis and formation of deep, dry, black eschar
Pain with rewarming Minimal Mild to moderate Severe None
Prognosis Excellent Good Often poor Extremely poor
Frostnip First Degree Frostbite.jpeg
Frostbite second degree.jpeg
Frostbite third degree.jpeg
Frostbite fourth degree.jpeg



  • Equipment
    • Appropriate clothing for environment, using a layering system
    • Avoid constricting items
    • Mittens are preferable to finger gloves and should be attached to the person; spares should be carried
    • Appropriate boots for environment/task that fit correctly
    • Be careful when removing gloves to perform tasks; never directly touch metal in extreme cold or in moderate cold if wet
  • Activity/ Difficulty
    • Avoid sweating by reducing exercise intensity if necessary
    • Avoid prolonged immobility
    • Avoid fatigue
  • Weather/ Environment
    • Do not climb in adverse weather conditions
    • Be aware of the risks associated with increased altitude
    • Be aware wind-chill effect
  • Planning
    • Leaders/commanders must ensure all are fit, trained, and capable of operating in proposed location/climate; this should take into account co morbidities and current medications
    • A thorough evacuation and medical plan must be in place before departure; this must include communications
  • Other/ Hygiene
    • Adequate calorie and fluid intake
    • Daily foot care
    • Buddy-buddy check system
    • Avoid alcohol and smoking



  • Return to safety
    • Consider turning back, and seek shelter from the elements
    • If one party member has a cold injury, others in the party at risk and all should be assessed and removed from the elements
  • Removal of clothing and jewelry
    • Socks and gloves should be replaced for dry pair
    • When removed, swelling may make redonning of boots problematic so only perform in a stable, sheltered location
    • Rings or similar items should be removed; subsequent swelling may make this impossible
  • Rehydration
    • Adequate hydration with oral (ideally warmed) fluids, consider IV if necessary
  • Rewarming (prehospital)
    • Place affected extremity in another person/s armpit or groin can be attempted for up to 10 minutes
      • The person can continue with additional improved protective measures if improved sensation (diagnosis is frostnip)[12]
      • If no improvement, the patient should get to the nearest warm shelter, seek medical attention (diagnosis is frostbite)
    • Avoid direct content with dry heat, can cause tissue damage via burning or mechanical disruption
    • Avoid walking on frostbitten feet if possible. Use splints and pads to minimize movement if walking is required[13]
    • Protect individuals from partial rewarming and refreezing during transport
      • If transport time <2 hours, “the risks posed by improper rewarming or refreezing outweigh the risks of delaying treatment for deep frostbite.”[14]
      • If transport time >2 hours, treatment for hypothermia is prioritized
      • Must protect the limb from refreezing
    • Prehospital medical facility (base camp medical center)
      • Immerse affected body parts in 37 to 39 °C water
      • If thermometer is not available, immerse unaffected limb first to ensure water is not too hot
      • Once rewarmed, critical not to let the limb refreeze
  • Dressing and blisters
    • Allow the limb to air dry following rewarming, do not rub
    • Apply allow vera or petroleum jelly to affected area, cover with dressing
    • Dressing should not be circumferential or too tight to allow for swelling. Dress between digits if possible.
    • Leave blisters intact; they indicate thawing.
    • Elevation of limbs can reduce blister size, minimize swelling.
    • Antibacterial baths 1-2x daily are recommended, dressings should be applied afterwards
  • Portable recompression bag (Gamow bag)
    • Hyperbaric pressure bags are widely available, provide simulated reduction at altitude
    • May provide two theoretical benefits[15]
      • Increased SpO2 (peripheral capillary oxygen saturation)
      • Reduction in altitude may minimize cold induced vasoconstriction, combat hypothermia
    • Not practical to directly rewarm; may be useful as in field adjunct
  • Other
    • Avoid tobacco use, smoking


  • Analgesia
    • Rewarming is often a painful process
    • Enteral and parenteral analgesia should be administered, including opioids
    • All patients should be started on Ibuprofen for its anti-inflammatory affects in addition to analgesic
    • 400 mg two or three times a day is a practical dose
  • Oxygen
    • Supplemental oxygen in theory increases tissue oxygenation
    • Oxygen supplementation at lower altitudes is debated
    • Maintain at least 90% saturations
  • Tetanus
    • Follow standard tetanus guidelines
  • Antibiotics
    • Controversial; prophylaxis has not been show to reduce amputation[16]
    • Administration is based on clinical judgement
  • Prehospital thrombolysis
    • In hospital tissue plasminogen activator [rTPA]) has resulted in reduced amputation rates
    • Effectiveness and use appears to be time dependent, similar to other vascular lesions in which thrombolysis is indicated[17]
    • Two case studies describe successful use of thrombolysis at K2 basecamp (need citations)
    • Currently there are no clear guidelines to recommend prehospital thrombolysis
  • Iloprost
    • Has been used in community hospitals in Canada[18]
    • Role in prehospital treatment has not been delineated
  • Sympathetic blockade/ Regional anesthesia
    • A single case report describes prehospital wrist block with good effect[19]
    • Can not currently be recommended based on the available evidence.
  • Telemedicine
    • Facilitates expert opinion in austere locations or with prolonged evacuation times


  • General Approach
    • Follow standard ATLS/ ACLS guidelines as needed based on clinical picture
    • Moderate or severe Hypothermia should be addressed first
    • This approach may mean initially ignoring a frostbitten limb
  • Clinical photography
    • Photography should be performed at admission and throughout treatment
    • Documents appearance, prevents need for repeated dressing removal
  • Imaging
    • Multiple imaging modalities can provide important prognostic information
    • Technecium99 (99Tc) triple-phase bone scanning accurately predicts amputation risk at 48 hours in 84% of cases[20]
    • MRA (magnetic resonance angiography) has been show to estimate level of tissue loss
      • Potential advantage over 99Tc scan because it allows direct visualization of occluded vessels, clearer demarcation of ischemia[21]
    • Fluoroscopic angioraphy shows vessel patency, should be considered in all patients in which thrombolysis is being considered
    • The role of CT angiography is not yet known.

Nonpharmacologic Treatment

  • Clothing/ Prevent constriction
    • Remove constricting items such as jewelry and rings because swelling will occur with thawing
  • Hydration
    • Patients are often clinically dehydrated due to cold diuresis, altitude, extreme activity
    • Oral vs intravenous fluids should be used based on clinical picture
  • Rewarming
    • Fully or partially frozen tissue should be rapidly and actively rewarmed
    • This should occur in a bath if possible, target temperature 37 to 39 °C
    • Povidone iodine or chlorhexidine should be added to prevent infection
    • End point of warming is red/purple appearance, tissue becomes pliable
    • Often takes 30 minutes, may take longer[22]
    • Rewarming may be painful, parenteral analgesia is often required
    • Return of sensation is a favorable prognostic sign
  • Blister management
    • Hemorrhagic blisters indicate injury into the reticular dermis
    • Clear blisters suggest a more superficial injury pattern
    • The wilderness medical society advises draining clear blisters, leaving hemorrhagic blisters intact[23]
    • This process should be performed sterile, may require local anesthetic
    • Hypothetically aids in wound care, tissue healing
  • Dressings/ Wound care
    • Goal: protect and prevent further tissue insult
    • Affected limbs should be splinted, elevated, dressed in a loose dressing
    • Padding between fingers/ toes is ideal
    • Topical aloe vera cream/gel should be applied under the dressing
    • Later, protective footwear should be used
  • Nutrition
    • Recovery requires a high-protein, high-calorie, individually tailored diets[24]

Pharmacologic Treatment

A stepwise approach to intra-arterial thrombolysis[17]
  • Analgesia
    • Rewarming is painful, pain should be addressed
    • All patients should be started on Ibuprofen for its anti-inflammatory affects in addition to analgesic
    • 400 mg two or three times a day is a practical dose
    • This can be increased up to 2400 mg/day
    • Aspirin should be avoided due to theoretical blockade of some prostaglandins which promote wound healing
  • Antibiotics
    • Should be given if suspected or proven infection
    • Prophylaxis is controversial; no evidence based guidelines or society recommendations are available
    • Consider in high risk patients such as malnutrition, immunosuppression, large total surface area of frostbite, etc
  • Tetanus toxoid
    • Standard tetanus booster can be administered
  • Thrombolytic therapy
    • Goal: reverse microvascular thrombosis, restore blood flow
    • Medications: TPA most commonly used
    • Delivery: targeted endovascular therapy is optimal
    • Literature
      • Twomey et al: in cases with no freese-thaw cycles, exposure < 24 hours or warm ischemia time of more than 6 hours, TPA resulsted in reduction in expected amputations[25]
      • Bruen et al: TPA within 24 hours reduced amputation rate from 41% to 10%[26]
      • Gonzaga et al: following thrombolysis, amputation rate was 31.4% for 472 at risk digits[27]
      • Cauchy et al: TPA reduced amputation rates (3.1%) compared to buflomedil (39.6%), but was inferior to iloprost (0%)[28]
    • Decision to administer
      • Injury must be severe with potential tissue loss, ocurred within the last 24 hours without freeze-thaw cycles
      • There must be no contraindications (i.e. recent trauma or surgery, bleeding diathesis, neurological impairment, etc)
      • Access to a critical care unit
      • Intra-arterial administeration is preferred
      • Co-administeration of papaverine may be needed to reduce vasospasm
      • Heparin should be used as an adjunctive treatment to minimize new clot formation
  • Iloprost
    • Prostacyclin analogue with vasodilatory properties, reduces capillary permability, supresses platelet aggregation, promotes fibrinolysis[29]
    • Note that it is not available in the US
    • Research
      • Cauch et al: reduced amputation among 407 patients that were at risk[30]
      • Case reports have also suggested benefit
    • Administered as an IV infusion
    • Advantages over TPA
    • Does not require radiological intervention, can be administered on a monitored ward, used more than 24 hours after injury, not contraindicated after trauma

Surgical Treatment Options

  • Fasciotomy
    • Acute Compartment Syndrome can develop with rewarming and the subsequent edema
    • Important to monitor for signs and symptoms
    • Note that this can be challenging in the context of frosbite
  • Amputation
    • Ideally, surgical amputation should be avoided until autoamputation/demarcation awaited.
    • Indications for early amputation include
      • Wet gangrene
      • Liquefaction
      • Overwhelming infection
      • Spreading sepsis
    • Imaging can help determine when this is necessary
  • Tissue care
    • Goal is to maintain and restore good quality tissue after healing
    • Attention should be paid to loadbearing and functionally significant areas
    • There are no evidence based guidelines for management
    • Secondary intention is likely the best course of action
    • Topical negative pressure facilitates wound healing[31]
    • Surgical flap is an alternative to secondary intention
    • Especially in areas significant areas (hands, feet, poor vascular bed)

Potential Adjunctive Therapies

  • Hyperbaric oxygen therapy
    • Hyperbaric oxygen therapy (HBOT) has been used to aid wound healing by increasing oxygen delivery to tissue
    • However, it requires patent microvasculature
    • Several case reports suggest benefit[32][33]
    • Animal studies are contradictory
    • More research is needed
  • Sympathectomy
    • Sympathectomy blocks the nerve, resulting in reflex vasodilation and increased blood flow[34]
    • This can be surgical or chemical
    • It is not currently recommended in acute frostbite management due to mixed results
    • However, in chronic complications including vasopspasm, hyperhidrosis, it may have benefit
  • Topical agents
    • Aloe vera is accepted as the best practices baesd on the available evidence
    • Further investigation into the following should be considered
      • Poly-l-arginine contained in lotion
      • Ganoderma triterpenids
      • Nanogel delivery method

Rehab and Return to Play


  • Variable, depends on affected area(s)
  • Goal: return the individual to the optimal function and independence.
  • Patients will require a multidisciplinary team:
  • Physicians
    • Occupational therapists
    • Specialist nurses
    • Physiotherapist
    • Prosthetist/ orthotist (if needed)
    • Mental health (if needed)

Return to Play/ Work

  • Can take several weeks or months depending on the severity of the injury
    • A player should not return to play the same day after thawing

Complications and Prognosis


  • Generally drive by severity
    • Frostnip: excellent
    • Frostbite grade 2: good
    • Frostbite grade 3: poor
    • Frostbite grade 4: extremally poor


  • Functional Loss
  • Cold sensitivity
    • Taylor et al in patients with significant frostbite injury[34]
      • 53% showed subsequent cold hypersensitivity
      • 40% numbness of the digits
      • 33% had reduced sensitivity to touch
  • Chronic pain
    • Common and troublesome for physicians
    • Early involvement with pain management specialist is recommended
    • Potential medications include Amitriptyline, Gabapentinoids
    • Early introduction of neuropathic analgesics may reduce the risk of developing chronic pain[35][36]
  • Chronic ulceration
    • Increased risk of chronic ulceration in patients with
      • Areas of poor tissue quality
      • Altered biomechanics and pressure areas
  • Must be monitored for malignant transformation[37]
  • Arthritis
    • Arthritis following frostbite is well reported[38]
    • Can also see
      • Localized osteoporosis
      • Subchondral bone loss
      • Epiphyseal injuries in the skeletally immature

See Also


  1. Post PW, Donner DD. Frostbite in a pre-Columbian mummy. Am J Phys Anthropol 1972;37(2):187–91.
  2. Golden FS, Francis TJ, Gallimore D, et al. Lessons from history: morbidity of cold injury in the Royal Marines during the Falklands Conflict of 1982. Extrem Physiol Med 2013;2(1):23.
  3. Larrey DJ, Hall RW. Memoirs of military surgery. 1st American from the 2d Paris ed, vol. 6. Baltimore (MD): Joseph Cushing; 1814.
  4. Harirchi I, Arvin A, Vash JH, et al. Frostbite: incidence and predisposing factors in mountaineers. Br J Sports Med 2005;39(12):898–901 [discussion: 901].
  5. Cattermole TJ. The epidemiology of cold injury in Antarctica. Aviat Space Environ Med 1999;70(2):135–40.
  6. Nemethy M, Pressman AB, Freer L, et al. Mt Everest Base Camp Medical Clinic “Everest ER”: epidemiology of medical events during the first 10 years of operation. Wilderness Environ Med 2015;26(1):4–10.
  7. Handford, Charles, Owen Thomas, and Christopher HE Imray. "Frostbite." Emergency Medicine Clinics 35.2 (2017): 281-299.
  8. Auerbach PS. Wilderness medicine. 6th edition. Philadelphia: Elsevier/Mosby; 2012.
  9. Image courtesy of weather.gov, "Wind Chill Chart"
  10. Sever C, Kulahci Y, Acar A, et al. Unusual hand frostbite caused by refrigerant liquids and gases. Ulus Travma Acil Cerrahi Derg 2010;16(5):433–8.
  11. Makinen TM, Jokelainen J, Nayha S, et al. Occurrence of frostbite in the general population–work-related and individual factors. Scand J Work Environ Health 2009;35(5):384–93.
  12. Syme D, Commission IM. Position paper: on-site treatment of frostbite for mountaineers. High Alt Med Biol 2002;3(3):297–8.
  13. McIntosh SE, Hamonko M, Freer L, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of frostbite. Wilderness Environ Med 2011;22(2):156–66.
  14. Zafren K, Giesbrecht G. State of Alaska: cold injuries guidelines. Juneau (Alaska): Department of Health and Social Services, Division of Public Health; 2014.
  15. Cauchy E, Leal S, Magnan MA, et al. Portable hyperbaric chamber and management of hypothermia and frostbite: an evident utilization. High Alt Med Biol 2014; 15(1):95–6.
  16. Malhotra MS, Mathew L. Effect of rewarming at various water bath temperatures in experimental frostbite. Aviat Space Environ Med 1978;49(7):874–6.
  17. 17.0 17.1 Handford C, Buxton P, Russell K, et al. Frostbite: a practical approach to hospital management. Extrem Physiol Med 2014;3:7.
  18. Poole A, Gauthier J. Treatment of severe frostbite with iloprost in northern Canada. CMAJ 2016;188(17–18):1255–8.
  19. Pasquier M, Ruffinen GZ, Brugger H, et al. Pre-hospital wrist block for digital frostbite injuries. High Alt Med Biol 2012;13(1):65–6.
  20. Cauchy E, Marsigny B, Allamel G, et al. The value of technetium 99 scintigraphy in the prognosis of amputation in severe frostbite injuries of the extremities: a retrospective study of 92 severe frostbite injuries. J Hand Surg Am 2000;25(5): 969–78
  21. Raman SR, Jamil Z, Cosgrove J. Magnetic resonance angiography unmasks frostbite injury. Emerg Med J 2011;28(5):450.
  22. McCauley RL, Hing DN, Robson MC, et al. Frostbite injuries: a rational approach based on the pathophysiology. J Trauma 1983;23(2):143–7.
  23. McIntosh SE, Opacic M, Freer L, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of frostbite: 2014 update. Wilderness Environ Med 2014;25(4 Suppl):S43–54.
  24. Kiss TL. Critical care for frostbite. Crit Care Nurs Clin North Am 2012;24(4): 581–91.
  25. Twomey JA, Peltier GL, Zera RT. An open-label study to evaluate the safety and efficacy of tissue plasminogen activator in treatment of severe frostbite. J Trauma 2005;59(6):1350–4
  26. 17. Bruen KJ, Ballard JR, Morris SE, et al. Reduction of the incidence of amputation in frostbite injury with thrombolytic therapy. Arch Surg 2007;142(6):546–51.
  27. Gonzaga T, Jenabzadeh K, Anderson CP, et al. Use of intraarterial thrombolytic therapy for acute treatment of frostbite in 62 patients with review of thrombolytic therapy in frostbite. J Burn Care Res 2015;37(4):e323–34.
  28. Cauchy E, Cheguillaume B, Chetaille E. A controlled trial of a prostacyclin and rt- PA in the treatment of severe frostbite. N Engl J Med 2011;364(2):189–90.
  29. Auerbach PS. Wilderness medicine. 6th edition. Philadelphia: Elsevier/Mosby; 2012.
  30. Cauchy E, Cheguillaume B, Chetaille E. A controlled trial of a prostacyclin and rt-PA in the treatment of severe frostbite. N Engl J Med 2011;364(2):189–90.
  31. Orgill DP, Bayer LR. Negative pressure wound therapy: past, present and future.Int Wound J 2013;10(Suppl 1):15–9.
  32. Kemper TC, de Jong VM, Anema HA, et al. Frostbite of both first digits of the foot treated with delayed hyperbaric oxygen: a case report and review of literature. Undersea Hyperb Med 2014;41(1):65–70.
  33. Dwivedi DA, Alasinga S, Singhal S, et al. Successful treatment of frostbite with hyperbaric oxygen treatment. Indian J Occup Environ Med 2015;19(2):121–2.
  34. 34.0 34.1 Taylor MS. Lumbar epidural sympathectomy for frostbite injuries of the feet. Mil Med 1999;164(8):566–7.
  35. Aldington DJ, McQuay HJ, Moore RA. End-to-end military pain management. Philos Trans R Soc Lond B Biol Sci 2011;366(1562):268–75.
  36. McGreevy K, Bottros MM, Raja SN. Preventing chronic pain following acute pain: risk factors, preventive strategies, and their efficacy. Eur J Pain Suppl 2011;5(2):365–72.
  37. Rossis CG, Yiacoumettis AM, Elemenoglou J. Squamous cell carcinoma of the heel developing at site of previous frostbite. J R Soc Med 1982;75(9):715–8.
  38. Kahn JE, Lidove O, Laredo JD, et al. Frostbite arthritis. Ann Rheum Dis 2005; 64(6):966–7
Created by:
John Kiel on 30 June 2019 22:54:19
Last edited:
24 March 2022 11:29:40