Frostbite is tissue damage caused by freezing. When skin and the tissue beneath it freeze, ice crystals form inside and between cells, destroying them and cutting off blood flow. It most commonly affects fingers, toes, ears, nose, and cheeks, and ranges from mild surface damage that heals completely to deep freezing that can result in amputation. About 69% of people who experience frostbite develop some form of long-term symptoms.
How Frostbite Damages Tissue
When your skin temperature drops low enough, ice crystals begin forming in the fluid between your cells. These crystals pull water out of cells, causing them to shrink and rupture. At the same time, the freezing damages the walls of small blood vessels, triggering clots that block circulation even after the tissue thaws. This is why frostbite injury often worsens after rewarming: the restored blood flow brings inflammation to already-damaged tissue, and the clots prevent blood from reaching the areas that need it most.
The combination of direct cell destruction and loss of blood supply is what separates frostbite from milder cold injuries. The deeper the freeze penetrates, the more tissue dies.
Frostnip vs. Frostbite
Frostnip is the mildest form of cold injury and sits at the beginning of the spectrum. Your skin turns red and feels very cold, and you may notice tingling or numbness. Frostnip doesn’t permanently damage tissue. Warming the skin resolves it completely.
Frostbite begins when the tissue actually freezes. The distinction matters because once true freezing occurs, some degree of lasting damage is likely.
The Four Stages
Frostbite is graded on a scale similar to burns:
- First degree: Numbness and pale skin with redness and swelling around the affected area. After rewarming, the skin may peel and feel prickly or burning. This is the most superficial form and typically heals without lasting tissue loss.
- Second degree: Blistering develops, with clear or milky fluid inside the blisters, surrounded by redness and swelling. The skin beneath is still alive, and recovery is possible, though some scarring or sensitivity may remain.
- Third degree: The full thickness of the skin is destroyed. Blisters fill with blood rather than clear fluid. The skin beneath appears blue-gray or black as tissue dies.
- Fourth degree: Freezing penetrates past the skin into muscle, tendons, or bone. The affected part turns black and hard. This stage often results in partial or complete loss of fingers, toes, or other extremities.
One important detail: you often can’t tell the true severity of frostbite until days or even weeks after the injury. Tissue that initially looks salvageable may darken and die as the full extent of blood vessel damage becomes clear. Doctors sometimes wait weeks before making final decisions about amputation for this reason.
What Frostbite Feels and Looks Like
The earliest warning sign is numbness. Your skin may first feel cold and prickly, then progress to feeling nothing at all. The loss of sensation is deceptive because once the area goes numb, you lose the pain signal that would otherwise tell you to get warm.
Skin color changes from red to white, grayish-yellow, or waxy-looking as freezing progresses. The tissue may feel unusually hard or wooden to the touch. Joint and muscle movement in the area becomes difficult or impossible. During rewarming, the skin turns red and swells, and you may feel intense burning, throbbing, or shooting pain. Blisters typically appear within 24 to 48 hours after rewarming, and their contents (clear fluid vs. blood) help indicate depth of injury.
Who Is Most at Risk
Anyone exposed to freezing temperatures can get frostbite, but certain factors raise the risk significantly. Homelessness is one of the strongest predictors, along with mental health conditions and drug or alcohol use, all of which can impair judgment about when to seek shelter or reduce awareness of cold exposure. Alcohol is particularly dangerous because it dilates blood vessels near the skin surface, creating a feeling of warmth while actually accelerating heat loss.
Peripheral vascular disease, which reduces blood flow to the hands and feet, also increases vulnerability. People with diabetes, smokers, and anyone taking medications that constrict blood vessels face higher risk. Previous frostbite makes you more susceptible to getting it again in the same area, partly because of lasting damage to blood vessels and nerves. Children are at special risk for a complication adults don’t face: frostbite can damage growth plates in developing bones, leading to permanent deformities.
First Aid for Frostbite
The most critical rule is: do not rewarm frostbitten tissue if there is any chance it will refreeze. Refreezing thawed tissue causes far worse damage than leaving it frozen. If you’re still in a situation where you can’t stay warm, it’s better to leave the tissue frozen until you can get to a safe, warm environment.
Once you’re in a warm setting, remove wet clothing and immerse the frostbitten area in warm water, ideally between 37°C and 39°C (about 99°F to 102°F). This is roughly the temperature of a warm bath, not hot. Water that’s too hot can burn tissue you can’t feel. Keep the area immersed for 20 to 30 minutes or until the skin becomes soft and sensation starts to return. Rewarming is painful, often severely so.
Do not rub the frozen area, use dry heat like a heating pad, or walk on frostbitten feet unless absolutely necessary. Friction and pressure can further damage frozen tissue. After rewarming, loosely wrap the area with clean bandages, placing gauze between affected fingers or toes to prevent them from sticking together.
Hospital Treatment
For severe frostbite (third or fourth degree), hospital treatment focuses on restoring blood flow to the damaged tissue. Doctors use imaging to assess which areas still have circulation and which don’t. When blood flow is absent, clot-dissolving medications can sometimes reopen blocked vessels and save tissue that would otherwise die. This treatment works best when given within 24 hours of rewarming and is not an option for everyone. People with bleeding disorders, recent surgery, or those who experienced repeated freeze-thaw cycles are not eligible.
Another medication that widens blood vessels can be started up to 72 hours after rewarming, which helps patients who don’t reach a hospital right away. The goal of all these treatments is the same: get blood flowing back to the frozen tissue before the damage becomes irreversible.
Long-Term Effects
Even after frostbite heals, the affected area is often never quite the same. In a review of nearly 500 frostbite patients across multiple studies, 69% had lasting symptoms. The most common long-term problem is increased sensitivity to cold. In one study of patients examined four to eleven years after frostbite, 53% reported heightened cold sensitivity and 66% had increased blood vessel spasms in the affected area, where fingers or toes would turn white and painful in response to even mild cold.
Chronic pain is another significant issue. One study found that 50% of frostbite patients reported ongoing pain, with 15% describing it as daily and intolerable. Half reported limitations in their social life, and about a third had poor emotional wellbeing years after the injury. Nerve damage can cause persistent numbness, tingling, burning sensations, or excessive sweating in the affected area. In one examination of soldiers, 38% had a disturbed sense of both cold and heat, and 18% had reduced ability to feel light touch.
Frostbite arthritis is a distinct condition that develops months or years after the initial injury. It resembles regular osteoarthritis, with joint stiffness, swelling, and pain, but it appears in joints that were frostbitten rather than following the typical age-related pattern. In soldiers who experienced frostbite of the hands, 100% still reported discomfort when exposed to cold four years later, and 83% experienced a persistent cold sensation in the affected hand.
Prevention
Frostbite can develop in minutes during extreme wind chill or within 30 minutes at temperatures around minus 27°C (minus 17°F). Dress in loose, dry layers. Tight clothing and tight boots reduce circulation to your extremities, which is exactly where frostbite strikes first. Mittens protect against frostbite better than gloves because your fingers share warmth. Cover your ears, nose, and cheeks, as these areas have high surface-to-volume ratios and freeze quickly.
Stay dry. Wet skin loses heat far faster than dry skin, and wet clothing against your body accelerates the process. If you start losing feeling in your fingers, toes, or face, treat it as an urgent signal to get warm, not something to push through. The numbness that precedes frostbite removes your ability to sense how much danger you’re in.