Frost bite
Frost bite is injury of tissues due to the action of a low temperature on them. Frost bite condition is rare in animals because they can withstand cold temperature due to their hairy coats and will instinctively seek shelter from inclement weather.
Udder and teats are commonly frozen in cows during exercise on frosty winter days. Besides the prepuce, penis and scrotum in horses, snout of pig, comb and wattles of birds, tip of the ear and scrotum of dogs, tail and distal extremities in other animals are commonly affected.
Frost bite usually occurs in a low temperature but it can also ensue in prolonged action of wet moderate above zero temperature (3-7ºc) since heat conductance of the skin is increased and heat emission is intensified by it.
Etiology of Frost bite
- Exposure to cold or chilling environment
- Contact with cold metal, glass, and liquids
- Iatrogenic freezing with cryogens like liquid nitrogen and nitrous oxide etc.
Classification of frost bite
Various degrees of frost bite recognized are-
- Mild Frost bite
- Moderate Frost bite
- Severe Frost bite
1. Mild Frost bite
Mild Frost bite caused by contraction of blood vessels (parts appear white) —> paralytic dilatation of blood vessels —> engorgement of vessels —> parts appear red and swollen —> thawing —> severe pain.
2. Moderate Frost bite
Moderate Frost bite caused by below 0oC temperature for longer period than mild —> injury of Blood vessels —> inflammation of the tissues —> redness of epidermis together with certain amount of necrosis and blister formation —> desquamation.
3. Severe Frost bite
Severe Frost bite caused by temperature falls for lower than freezing point —> impaired circulation of blood and lymph —> parts undergoes necrosis and gangrene may ensure.
Clinical Signs of frost bite
- Loss of sensation in the affected part
- Cyanotic or pale appearance of frozen part
- Moderate edemas, pain and very cold to touch
- Shivering
- In neglected cases, necrosis and sloughing of skin
Treatment of frost bite
Withdrawal from cold to stop further worsening of the condition.
Warming of frost bitten extremities, and restoration of blood and lymph circulation, Frozen animals must be immediately put in a warm housing to restore body core temperature. Hot water bag or hot pad may be used for warming; frozen parts should be bathed in increasingly warm water until pink colour is restored.