[From Tufts January 2012 Issue]
Frostbite in dogs most commonly occurs as a result of prolonged exposure to subzero temperatures. It usually affects extremities of the dog’s body such as the tips of the ears, tail, feet and toes. Those areas, while highly exposed to the elements, lack insulating muscle and fat. The worst cases of frostbite can cause dogs considerable pain and put them at risk for infection.
“Frostbite should be avoided at all costs; however, accidents do happen,” says John Anastasio, DVM, a resident in emergency and critical care at Cummings School of Veterinary Medicine at Tufts University. “It is most likely to happen in extreme cold, but is fairly unlikely on the typical winter day. Beware of it if a newsworthy cold snap is anticipated. The affected areas should be warmed with warm — not hot — compresses, and veterinary attention should be sought immediately. The extent of damage may not be immediately apparent, so close monitoring of the affected areas over several days is important.”
Blood vessels constrict
If an exposed area of the body becomes very cold because of freezing temperatures, the blood vessels in that area constrict. This reflex helps conserve core body heat, but with less blood pumping to the area, the tissue can become dangerously cold. Water within the cells of the tissue begins to crystallize, damaging cell membranes and proteins. Cellular dysfunction and eventually cell death follow.
If the decrease in temperature and duration of exposure are mild, permanent damage is unlikely, Dr. Anastasio says. “However, as the severity of frostbite increases, so does the likelihood of more extensive tissue death. Over time, the non-viable tissues will gradually become more discolored, hardened and eventually slough away from the body.”
There are four degrees of frostbite, much like there are several degrees of burns to the skin. The first, called frostnip, affects only the skin’s top layer, and the frozen skin doesn’t become permanently damaged. The skin appears pale or gray in color and will be hard and cold to the touch. Second-degree frostbite causes the skin to freeze and harden, but the deep tissues aren’t affected. Fluid-filled blisters form, and after several days they become hard and blackened, but usually heal within one month.
With prolonged exposure to freezing temperatures, third- and fourth- degree frostbite can occur. Muscles, tendons, blood vessels and nerves freeze, and the affected area feels hard and waxy to the touch. Nerve damage and permanent loss of feeling can develop. Affected areas of skin may need to be removed to prevent infection and allow healing. Frostbite can become excruciatingly painful and often necessitates treatment with morphine-like medications.
Depending on the size of the wound, healing can take several weeks to months. In the areas of dogs’ bodies typically affected by third- and fourth-degree frostbite, simple removal of the affected skin and suturing are enough. Skin grafts and other reconstructive procedures to replace the missing skin are usually unnecessary. If you suspect your dog has frostbite, apply warm compresses or soak the affected areas in a bowl or tub of warm water. Don’t heat the area with appliances such as a heating pad or hair dryer, and don’t rub the area. Keep your dog as warm as possible and seek immediate medical care.
The veterinarian will examine your dog to assess the extent of the injury, although it may take several days to determine how much tissue has actually died. Treatment usually involves cleaning and bandaging the wounds and providing antibiotics and pain medication. In most cases, surgery isn’t necessary.
While many dogs enjoy being outside in winter, owners have the responsibility for frostbite prevention on extremely cold days. And it’s actually simple: Limit exposure in subzero weather.
Karen Lee Stevens is a writer in
Santa Barbara, Calif.