Hypothermia and Frostbite in Cats and Dogs
Written by Small Door's medical experts
Winter might bring to mind pleasant thoughts of tossing snowballs to your dog in the yard or cuddling with your cat beside a roaring fire, but it also comes with dangers. Just like humans, dogs and cats are susceptible to colder temperatures. Hypothermia and frostbite can affect all pets who venture outdoors for too long in the cold.
In This Article
Hypothermia is more than just a case of the chills. The condition, which results in subnormal body temperatures, is the result of heat loss.
As you may have learned in high school science classes, there are four basic ways heat can be lost from a body: convection, conduction, radiation, and evaporation. In convection, air moving past the body surface transfers heat, like what happens in a cold wind. In conduction, colder objects in contact with the skin transfer heat away from the body, as can happen if a pet lies on a cold surface like ice or snow. Radiation transfers heat between the body and an object not in contact with the skin (think about how heat radiates away from hot asphalt), while evaporation happens when moisture on the skin or in the respiratory tract dissipates into the air, carrying heat with it.
Phew. Still with us? To recap: cold wind, cold surfaces, radiation, and evaporation from panting or wet fur and skin can all cause heat loss. This makes certain types of winter weather and activities especially dangerous for pets, such as:
Going for a walk or being outside in very cold temperatures (particularly without any protection such as booties and a coat)
Being outside in freezing rain or snow
Taking a wet dog or cat outside for extended periods
Some types of cats and dogs are more vulnerable to cold than others. For example, dogs with thin coats and little body fat, like greyhounds, will have a lot more trouble with the cold than dogs with undercoats and outer coats, like Bernese Mountain Dogs, German Shepherds, Labradors, Huskies or Malamutes. Hairless cats and dogs are especially at risk, and small breed dogs typically get cold more quickly than larger breeds.
A good rule of thumb for determining if it is safe for your dog to go for a walk or spend time outside in the winter is to think about how you would feel outside in those conditions. If you take your hairless dog outside, he feels as cold as you would without clothes on. Imagine you’re wearing a sweater (if your dog has a thin coat), a jacket (if your dog has a double coat), or a thick winter parka (if your dog is a Northern breed like a Malamute).
But bear in mind that even though their fur will help to protect them against the cold, your pet’s extremities are still at risk of frostbite.
Frostbite occurs when skin is exposed to frigid temperatures for too long. In cold temperatures, blood vessels that are close to the skin start to narrow, in order to preserve body temperature by diverting blood flow towards the core. While this mechanism protects the organs, it means that blood flow to the extremities is reduced, which can lead the tissue to freeze and become frostbitten.
Depending on the temperature and wind chill, frostbite can occur after long periods of exposure, or, in very cold conditions, within minutes. Ears, noses, toes, paws and tails are the areas most commonly affected in dogs and cats, but frostbite can affect any part of the body.
There are several stages of frostbite. The first and mildest stage is called frostnip. In people, this is when we might notice that our skin is red and numb, though the color change may not be as obvious in cats and dogs, especially in darkly pigmented areas like noses and paw pads. This stage is reversible once the skin is warmed.
The second stage, known as superficial frostbite, turns the skin pale or waxy. This stage can cause damage, including a mottled appearance or even blisters as the skin warms.
The last stage, deep frostbite, affects all the layers of the skin and even the tissues that lie below. There is a total loss of sensation, which can affect muscles and joints, and the skin typically turns white or bluish gray. Once the skin is warmed, large blisters form within one to two days. The area eventually hardens and turns black as the tissue dies.
Medical intervention is necessary for some superficial cases and all deep frostbite cases. Dead tissue may need to be removed, and the wounds created by frostbite will require wound management to avoid infection and ensure proper healing.
Once the core body temperature of a cat or dog drops below 94°F (34.4°C), their bodies struggle to regulate their temperature. Without treatment, hypothermia affects every organ system and can cause heart problems, difficulty breathing, drops in blood sugar, neurological effects, depressed immune systems, and death.
The initial warning signs of hypothermia include:
Intense shivering
Drowsiness and lethargy
Ataxia (loss of coordination)
Heat-seeking behavior
As hypothermia progresses, cold animals will stop shivering or looking for heat, as their bodies can no longer work to stabilize their temperature. This leads to a hypothermic spiral, where they just get colder and colder. As each organ system is affected, you may start to notice related symptoms, like slower pulse and respiratory rates.
As mentioned above, there are several stages of frostbite. Initially, you may notice the following symptoms:
Coldness of the area when touched
Discoloration of the skin (initially red, then will turn pale/grey/bluish)
Shivering
Ice or snow stuck to the body
Pain and/or numbness
As the frostbite progresses, you may also notice:
Swelling of the affected area
Blisters or skin ulcers
Areas of blackened or dead skin
As frostbitten tissues thaw, they may become red, inflamed and very painful for your pet.
It’s worth noting that symptoms of frostbite may take several days to appear, so it’s very important to watch out for initial danger signs of coldness such as shivering, and take great care when your pet is exposed to cold weather. Also remember that pets with conditions that cause reduced blood flow, such as heart disease or diabetes, are at greater risk of frostbite.
Even with the best of intentions, our pets sometimes get exposed to dangerously cold conditions. The first thing you should do if you suspect your pet has hypothermia or frostbite is to get them to a warm, dry place as quickly as possible. If their temperature is below 98°F (36.7°C), or they are very sluggish and unresponsive, you should take them directly to the nearest emergency veterinarian for treatment.
It’s important to note that, if you find your pet or another animal outdoors, check to make sure they aren’t stuck to ice before moving them, as this could tear their skin. If they are stuck, pour a small amount of lukewarm water (not hot) onto the affected area to help melt the ice and free them.
Once indoors, begin warming your pet whilst you call your veterinarian for further advice. You should attempt to warm them slowly and steadily – if they are warmed too fast, this can risk rapidly dilating their constricted blood vessels, which can cause a life-threatening case of shock.
A great way to raise your pet’s body temperature is to place them at a safe distance (several feet) from a space heater. You could also wrap a hot water bottle in a towel and place it next to them, or use a wrapped heating pad on a very low setting. Never use an unwrapped water bottle, unwrapped heating pad or hair dryer, as these could burn their skin. Other alternatives include warming some blankets in the dryer and wrapping your pet in the warm blankets, or bundling yourself up with them to help transfer your body heat to them!
It’s also important to note that you should NOT put your pet in warm water to heat them. This can lead to them heating up too quickly, which as mentioned earlier can be very dangerous.
Whichever method you choose to warm your pet up, supervise them throughout and keep checking the temperature of their skin to ensure it doesn’t get too hot.
Depending on your pet’s clinical signs and temperature, your veterinarian may recommend that you bring them in for treatment, or if may be safe to continue warming them up and monitoring them at home. At home, you should check their temperature every 10 minutes (you can use a regular human thermometer to do this. And although they may not enjoy it, it’s best to take an animal’s temperature rectally.)
Once their temperature is above 100°F (37.8°C), you can remove the heater/hot water bottle/heating pad to avoid overheating, but ensure you keep your pet in a warm, dry room. Continue to monitor your pet until they reach normal body temperature (which is 101-102.5°F (38.3-39.2°C) for dogs and cats), and are walking around and behaving normally again.
As soon as any potential hypothermia is treated, check your pet for signs of frostbite. Look for changes in color to the ears, nose, paws, and tail, as well as any part of the body that may have come into contact with the ground if they were laying down outdoors. If the skin is pale or has turned a dark color, contact your veterinarian for further advice, and keep an eye on the area over the next few days to see if the skin begins to die. In the meantime, restrict activity to reduce further damage, as frostbite associated numbness will make it hard for your pet to move carefully.
Most cases of frostnip recover within a matter of hours. More severe frostbite can take longer, and if the skin has been permanently damaged, your veterinarian may need to debride and clean the wound, or even amputate.
Luckily, frostbite and hypothermia are preventable. The easiest way to prevent them is by limiting your pets’ time outdoors in cold and wet weather. You should also talk with your veterinarian about safe temperature ranges for your pet’s breed, age, and condition. Any pet with a condition that might make them cold-intolerant, for example, will be at a higher risk of hypothermia.
Here are some things you can do to keep your pet safe:
Dress your pet in appropriate, protective cold-weather gear, like coats and booties.
Restrict outdoor time on days with freezing temperatures. Reduce the length of your dog’s walks and engage them with indoor activities instead.
If possible, outdoor cats should be kept indoors during dangerously cold weather conditions. If this is not possible, make sure they have warm, dry places to return to at all times. You might consider purchasing an outdoor heated box to help provide them with refuge from the cold.
Prevent your dog from swimming during the winter months or from walking on frozen bodies of water.
Frequently check your pet for signs of frostbite or hypothermia while outdoors, and whenever they come back indoors after being outside in particularly cold weather.
Observe your pet for signs of discomfort, like shivering, holding their paws off the ground or reluctance to walk. Take them indoors immediately whenever you notice such signs, and monitor them until they’ve warmed up.
Armed with this knowledge, both you and your pet will be prepared to get through the winter months safely.
Remember, we’re here for our Small Door members 24/7 – contact us via the app for immediate assistance if you’re concerned your pet may be suffering from hypothermia or frostbite.
