What is frostbite?
Frostbite or congelatio in medical terminology is the damage that is caused to skin and other tissues due to extreme cold. When the environmental temperature drops below 32°F (0°C), blood vessels close to the skin start to narrow or constrict. This constriction of the blood vessels helps to preserve core body temperature by diverting blood toward the core and away from the cooler parts of the body. In extreme cold or when the body is exposed to cold for long periods, this protective mechanism can reduce blood flow in some areas of the body, especially the extremities, to critically low levels. The combination of cold temperature and reduced blood flow can allow the tissues to freeze, causing severe tissue injury. Frostbite is most likely to happen in body parts farthest from the heart and in tissues with a lot of exposed surface area.
Where is a dog more likely to get frostbite?
The paws, ears and tail are the most common tissues to be affected. If a dog is wet or damp, these areas are more vulnerable to frostbite.
What are the clinical signs of frostbite?
The clinical signs associated with frostbite include:
- Discoloration of the affected area of skin - this discoloration is often pale, gray or bluish
- Coldness and/or brittleness of the area when touched
- Pain when you touch the body part(s)
- Swelling of the affected area(s)
- Blisters or skin ulcers
- Areas of blackened or dead skin
As frostbitten tissues thaw, they may become red and very painful due to inflammation.
"The clinical signs of frostbite may take several days to appear..."
The clinical signs of frostbite may take several days to appear, especially if the affected area is small or non-weight bearing (such as the tip of the tail or ears). Severely frostbitten areas will becomenecrotic or die. As the tissue starts to die, it changes to a dark blue to black color; then, over a period of several days to weeks, it sloughs or falls off. During this time, pus may form or the tissue may develop a foul smell, due to secondary bacterial infection.
Dogs with heart disease, diabetes mellitus or other conditions that cause reduced blood flow to the extremities are at greater risk for frostbite.
How is frostbite diagnosed?
Diagnosis is usually based on the medical history and physical examination. If the dog was exposed for a prolonged time or to extremely cold temperatures, blood and urine tests may be performed to look for damage to internal organs.
How is frostbite treated?
If you suspect your dog has frostbite, you should seek medical attention immediately. Interim first aid suggestions that you can begin include:
- Move your dog to a warm, dry area as quickly and as safely as possible.
- If your dog is suffering from hypothermia or low core body temperature, treat the hypothermia first. Do this slowly by wrapping its body in warm dry towels or blankets and placing hot water bottles wrapped in towels near its body.
- DO NOT rub or massage the affected area.
- If you are outdoors, DO NOT warm a frostbitten area if you cannot keep it warm. Additional cold exposure or refreezing will more severely injure the tissues.
- You may carefully warm the affected area with warm (NOT HOT) water. The recommended water temperature is 104 to 108°F (40 to 42°C) - at this temperature, you should be able to comfortably place your hand in the warm water. If the water is too hot, you may cause more damage than not using any water at all. You may apply warm water compresses or soak the affected area in a bowl of warm water. DO NOT use direct dry heat such as a heating pad or hair dryer.
- After you have warmed the area, pat it dry carefully and thoroughly.
- While traveling to the veterinarian for further medical treatment, keep your dog warm by wrapping the pet in dry towels or blankets that have been warmed in the clothes dryer.
- DO NOT give any pain medication unless specifically instructed by your veterinarian. Many human pain relievers, including acetaminophen and aspirin can be toxic to pets.
How will my veterinarian treat frostbite?
Your veterinarian will examine your dog and treat any other conditions, especially systemic shock or hypothermia. Since the thawing tissues are extremely painful, your dog will probably be given pain medication. Antibiotics are used to prevent secondary bacterial skin infection if tissue necrosis or death is suspected. Some dogs will require amputation of a severely affected body part.
What is the prognosis for frostbite?
The prognosis for frostbite depends on the extent of your dog's injuries. Mild cases of frostbite usually resolve with little permanent damage while more severe frostbite may result in permanent disfiguration or alteration of the affected tissues. In extreme cases, amputation or surgical removal of the necrotic tissues is required. Your veterinarian will discuss the appropriate diagnostic and treatment plan for your dog.