frostbite

Last edited 02/2021 and last reviewed 03/2021

Frostbite is a thermal tissue injury caused when tissue is exposed to sub-zero temperatures (in degrees Celsius) long enough for ice crystals to form in the affected tissue.

• the term frostbite may cover a wide spectrum of injuries, from minimal tissue damage to substantial tissue necrosis with amputation 
• severity of frostbite injury is proportional to the temperature, duration of exposure, and amount and depth of frozen tissue

Historically the condition was seen in military work in the field

• however in the in the past 20 years the number of civilian cases has increased
• those who partake in winter sports such as skiing, hiking, mountain and ice climbing
• it is also common in the elderly or the homeless during cold spells and individuals in which behavioural and physiological compensation can be left wanting
• in addition, industrial injury and malfunctioning or misuse of equipment using NO or CO2 have also been described
• its likelihood is increased if accompanied by wind or high altitude, as encountered by climbers and explorers (1,2)

Frostbites are commonly seen in hand and feet which accounts for 90% of cases. In addition they may also affect the face (nose, chin, earlobes, cheeks and lips), buttocks/perineum (from sitting on metal seats) and penis (joggers and Nordic skiers) (2).

Clinical features:

• loss of sensation and a pale, waxy, bluish skin discolouration (cyanosis)
• blisters and oedema may be present in the affected areas
• favourable clinical finings include (3)
• clear fluid in the blisters, retained sensation and normal skin colour
• poor prognostic signs include cloudy or haemorrhagic (bloody) fluid in the blisters, cyanosis, lack of oedema and firm skin in the frostbitten area

Click here for an example image of this condition

Risk factors for the development of frostbite other than temperature include (4,5):

• physical immersion in water
• wind-chill
• fatigue
• malnutrition
• smoking
• alcohol and substance abuse
• medical comorbidities including peripheral vascular disease, diabetes, neuropathies, dementia and mental illness

Frostnip

• a precursor to frostbite that presents with symptoms similar to grade 1 frostbite
• fully reversible and holds no long-term effects

Reference:

• (1) Hallam MJ et al. Managing frostbite. BMJ. 2010;341:c5864.
• (2) Handford C et al. Frostbite: a practical approach to hospital management. Extrem Physiol Med. 2014;3:7.
• (3) Imray CH. A clinical review of the management of frostbite.Journal of the Royal Army Medical Corps 2011;157(1):73-8.
• (4) Handford C, Buxton P, Russell K, Imray CE, McIntosh SE, Freer L,et al. Frostbite: a practical approach to hospital management.Extreme Physiology & Medicine 2014;3:7
• (5) McMahon JA, Howe A. Cold weather issues in sidelineand event management. Current Sports Medicine Reports2012;11(3):135-41