Frostbite is a freezing injury of the 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.

Note: Recognition of frostbite can be more challenging in patients with darker skin tones, where colour changes may be less apparent.

Protect the affected area

• Handle gently and protect from further trauma or pressure.

Remove constricting items

• Remove jewellery or tight clothing.

Thawing decisions

• No risk of refreezing: initiate thawing as soon as possible.
• Risk of refreezing: keep tissue frozen; refreezing after thawing significantly worsens injury.

Analgesia

• Rewarming is painful.
• Use NSAIDs (e.g. ibuprofen or aspirin) with paracetamol, escalating as needed and with what is available.

Rapid active rewarming is the treatment of choice.

If not feasible, use passive methods (warm environment, axillae, shared body heat).

Warm water immersion (preferred where possible)

1. Temperature:

• Immerse in 37–39°C water.
• If no thermometer is available, test with your elbow (warm, not hot).
• Maintain temperature and stir regularly.

1. Endpoint:

• Rewarming is complete when tissue becomes red/purple, soft, and pliable (typically ~30 minutes).

1. Aftercare:

• Dry gently (pat dry; do not rub)
• Elevate to reduce oedema
• Move to a heated environment as soon as possible
• If evacuation is delayed, consider 30-minute warm water rewarming twice daily

Accurate staging guides management and can improve outcomes, including digit salvage.

While frozen, mild and severe frostbite may appear similar. True severity often becomes clear only after rewarming and may evolve over several days.

Assess severity after rewarming using the Cauchy classification.

The Cauchy classification predicts the natural course of frostbite if untreated.

Blister management

• Leave blisters intact where possible
• Aspirate tense, clear blisters only if high risk of rupture (apply dry dressing) or if they are restricting movement at joints
• Do not aspirate or debride haemorrhagic blisters

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)

Clinical photography

• 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

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 for evacuation, splint and protect, minimising movement (e.g. padded, loose footwear)

• Grades 2–4 respond very well to early treatment with thrombolysis or iloprost, ideally within 24 hours, but up to 72 hours post-rewarming.
• These therapies are not available in all settings, early transfer to a unit that provides them is essential.