Frostbite is a freezing injury of skin and underlying tissue caused by cold exposure.

Suspect frostbite in patients with:

• Exposure to temperatures <10 °C for minutes to hours
• Inadequate protection (e.g. exposed skin, wet or insufficient clothing)
• Pain, tingling, or loss of sensation in digits or extremities

Skin may appear normal or pale, sometimes with a clear line of demarcation.

• While tissue remains frozen, severity is difficult to assess; treat all cases as potentially severe until rewarmed.
• Many UK patients present after partial or complete rewarming, when severity may already be apparent.

Note: Recognition may be more challenging in darker skin tones, where colour change is less visible.

Protect the affected area

• Handle gently; avoid trauma or pressure

Remove constricting items

• Remove jewellery or tight clothing

Analgesia

• Rewarming is painful
• Use NSAIDs (e.g. ibuprofen or aspirin) with paracetamol
• Escalate as needed (opioids may be required)

• Take photographs when frozen, post-thaw, and serially to document progression and support ongoing care
• Use the patient’s own phone to take photographs, ensuring images remain with them for continuity of care

Rapid active rewarming is the treatment of choice

Warm water immersion

Temperature:

• 37–39 °C water (antiseptic such as povidone iodine may be added)
• Use elbow to test if no thermometer (warm, not hot)
• Maintain temperature; stir regularly

Endpoint:

• Tissue becomes red/purple, soft, and pliable (30 min or longer)

Aftercare:

• Pat dry (do not rub) or air dry.
• Elevate to reduce oedema

• Assess extent of injury (e.g. proximal spread along digit)
• Identify blisters:
• Clear = more superficial
• Haemorrhagic = deeper injury
• Use Cauchy classification to grade the frostbite and guide management
• Reassess as injury evolves and demarcates over time

• Grading guides management and improves outcomes, including digit salvage
• Assess severity after rewarming using the Cauchy classification
• The Cauchy Classification predicts the natural course of frostbite if untreated

• Grade 1: supportive care only
• Grades 2–4: benefit from early definitive treatment:
• Iloprost or thrombolysis
• Ideally within 24 hrs, up to 72 hrs post-rewarming

Iloprost (Grades 2–4)

• Treatment of choice in most cases; Improves digit salvage.
• Generally well tolerated; the main adverse effects are hypotension and headache, which can often be reduced by slowing the infusion rate.
• Dose: 0.5–2 ng/kg/min IV, administered via syringe pump over 6 hours daily for 5 days.
• Always check contraindications, precautions, and side effects before use

Alteplase (Grade 4 and < 24 hrs since freezing)

• Alteplase IV 0.15mg/kg/hr for 6hrs
• Enoxaparin 1mg/kg SC twice daily for 12 days

Surgery

• In severe cases of frostbite, surgical intervention may be required. This is usually carried out by vascular or plastic surgeons, depending on local practice. The extent of soft tissue necrosis typically becomes apparent after 1 to 4 weeks, at which point necrotic tissue can be removed. Amputation should generally be postponed until the full extent of tissue damage is clearly defined. Demarcation typically takes 4 to 12 weeks to develop post-injury. However, if there are signs of infection earlier amputation may be necessary.

Blister management

• Aspirate tense, clear blisters
• Aspirate or debride haemorrhagic blisters if high risk of rupture or if they are restricting movement at joints

Dressings and protection

• Apply sterile dressings to broken skin
• Splint in an anatomical position and pad
• Avoid tight/circumferential dressings (anticipate swelling)
• Aloe vera may be applied (limited evidence, unlikely to harm)

Antibiotics

• Not routinely indicated
• Use only if there are signs of infection, associated trauma, or sepsis

Tetanus prophylaxis

• Administer according to standard guidelines

Hydration

• Encourage oral fluids; avoiding hypovolaemia may support recovery

Ambulation

• Avoid using rewarmed extremities
• If unavoidable, splint and protect, minimising movement (e.g. padded, loose footwear)

Encourage

• Avoid alcohol and tobacco