Frostbite in Cats

Initially, frostbite is not painful and the area may even lack sensation, but as the cat thaws out, the affected areas become extremely painful. The damage to tissue can be so severe that salvage is not possible, and amputation may be required. 

Frostbite occurs when a cat is exposed to extreme cold and the tissue of extremities (such as the ear tips, paws, or tail tip) dies off. This happens because the body protects vital organs by re-routing blood away from the skin and to the core. Unfortunately, the combination of poor circulation and ice crystals inside living cells leads to tissue death.

The full extent of the damage done by frostbite may not become evident for several days. Also, be aware that a cat with frostbite is also likely to be suffering from the effects of hypothermia (dangerously low body temperature). 

• The cat feels cold to the touch
• The paws, tail tip or ears feel icy
• Initially, the affected area may be numb or lack sensation
• Fur falls out, leaving bald, inflamed areas
• Blistering of the skin
• Skin has a discolored or grayish appearance
• Layers of skin may flake and peel away
• Days later the area may swell and turn black
• Ear tips may curl and shrivel
• A few days after exposure to the cold, frostbitten tissue may start to smell as secondary infections set in.

Types: 

Experts measure frostbite in 3 levels, or “degrees,” based on the layers of skin that are affected.

• Frostnip (first-degree frostbite) - Mildest form affecting only the top layer of skin causing minor skin discoloration.
• Superficial frostbite (second-degree frostbite) - Moderate form affecting the top two layers of skin, requires veterinary care. 
• Deep frostbite (third-degree frostbite) - Most dangerous form affecting all three skin layers and can result in bacterial infections, tissue necrosis and amputation. Requires immediate veterinary care.

Ultimately, frostbite is caused by exposure to  temperatures below 0 centigrade (37 Fahrenheit). Those cats which are most vulnerable are those without shelter, are sick and debilitated, or are suffering from conditions such as diabetes or heart disease which impair circulation. 

Wind chill or a wet coat can significantly increase the risk of frostbite, and the longer the cat is exposed to low temperatures the greater the risk. Another factor is direct contact with metallic objects, which can become extremely cold.

Diagnosis is made largely by a history of cold exposure and visual inspection of the type and  distribution of the cat's lesions. Many cases that are highly suspicious of frostbite will be treated as such, and if they fail to respond to treatment further diagnostics be pursued. 

In some cases, the veterinarian may need to rule out other conditions with a similar appearance, such as sun damage to ear tips, burns, vasculitis, and immune-mediated diseases such as lupus. However, most of these conditions will have been present prior to exposure to the cold, so targeted questioning of the owner can help the clinician reach a rapid diagnosis.

It may be appropriate to run screening blood tests to check for organ damage as a result of hypothermia. Also, skin biopsies of the affected area can rule out other conditions and guide the clinician as to how likely the affected tissue is to recover. 

Immediate First Aid

If you find a cat with frostbite, they are likely to be suffering from the extreme cold. Prompt first aid includes taking the cat out of the cold and providing warmth whilst you transport them to the vet. 

• Do not rub the affected areas to try and restore circulation, as it will further traumatize already damaged tissue
• Do not apply direct heat, which would cause peripheral vessels to shut down further
• Do not give any pain medication (leave this to the vet)
• Do soak the affected areas in warm (blood temperature) water
• Do wrap the cat in a warm blanket

Veterinary Treatment

Your vet will continue the warming process using warm intravenous fluids to re-establish circulation and raise the core temperature. Other therapy includes:

• Pain relief (given once a good blood supply to the kidneys is ensured)
• Applying warm dressings to the extremities
• Antibiotics to reduce the risk of secondary infections

In the next few days as the full extent of tissue die back is revealed, the vet will: 

• Assess which tissue is vital and which is dead
• Debride away dead tissue. This may need to be repeated every couple of days, until a margin of healthy tissue is established. The cat will need either sedation or anesthesia for this procedure.
• If necessary, amputate the affected extremity

The full extent of the frostbite may not be evident for seven to ten days, at which point radical surgery may be required to remove an affected tail tip, ear, or toe. Whether amputation is necessary depends on the severity of the frostbite.

Mild cases of frostbite, with the aid of pain relief and antibiotics, are likely to make a full recovery. More serious cases, if they survive the hypothermia, may need surgery and be left with the permanent loss of  part of their anatomy. 

If amputation is required then the cat must not be allowed to lick or chew the sutures, and will need to stay indoors until healing is complete, around ten days later. It may be wise to substitute shredded paper for cat litter, so the latter does not stick to the wound. 

Once the sutures are removed, the cat can go back to a normal lifestyle, with the proviso that they are given shelter from extreme weather.