You heard the warning as a child when you went out to play in the winter: “Don’t stay out too long or you might get frostbite!” Hopefully you listened to that advice and never suffered from the painful condition. But if you've never experienced it, you may not know exactly what frostbite is.

Frostbite happens when extremely cold air comes in contact with exposed skin; it often starts with your fingers, toes, nose, ears, cheeks or chin. Your body is trying to stay warm and keep vital organs (heart, liver) functioning properly, so it draws blood away from your extremities toward your core. When that happens, your body tissue starts to freeze.

The stages of frostbite

Woman trying to warm her cold hands If your exposed fingers or nose start to get red, cold and possibly tingly, that's called frostnip, which is the first stage of frostbite. (Photo: Ferenc Cegledi/Shutterstock)

The first stage of frostbite is called frostnip, in which the affected parts of your body get red and cold, according to the Mayo Clinic. As frostbite progresses, your skin might begin to become numb or get the "pins and needles" feeling. You may start to get clumsy due to joint stiffness or numbness.

The good news is that frostnip doesn't permanently damage skin. You should head inside, drink some warm beverages and call your doctor if you develop pain, blisters or a fever.

However, if frostnip progresses into frostbite, your reddened skin may start to turn pale or white, the Mayo Clinic says. It also may start to feel warm again, a sure sign that it’s not just a mild case anymore. When your skin is reheated or thawed from this stage, it may turn blue or purple, and fluid-filled blisters may begin to form.

Once frostbite enters an advanced stage, you may experience complete numbness and lose all sensation of cold or pain in the affected skin. Blisters will form at this stage after a day or two, and the frozen tissue will turn first blue and then black as it dies.

If you suspect frostbite, seek medical attention immediately. Whatever you do, don’t put the affected area in hot water; your skin may be too numb to feel pain if the water is too hot and you may burn yourself, the Mayo Clinic says. Instead, soak your skin in warm water (about 105 degrees F) until it warms up. If you can't soak the area, apply a wet washcloth.

How to prevent frostbite

Woman bundled up for cold weather Layers are your friend when it comes to preventing frostbite, from wearing a hood over a wool hat (like this woman) to wearing multiple shirts or pairs of socks. (Photo: simonovstas/Shutterstock)

Layer up. Your innermost layer should be something that will not retain moisture. The second layer should be insulating, and your outermost layer should help protect your body against wind and rain.

Protect your extremities. Wear warm socks on your feet since they are particularly susceptible to frostbite. Layering works here too — wear wool ones over socks that’ll help keep your feet dry.

As far as your hands, choose mittens when you can instead of gloves, since mittens allow your fingers to touch each other and share body heat. Don't take them off to use your smartphone, advises WebMD. If you must use your phone while you're outside, look for gloves with textured fingertips that allow for swiping. Also, wear ear muffs or a hat with ear flaps to protect your ears.

Limit time outside in frigid weather. In below-zero temperatures, frostbite can happen in just 5 to 10 minutes, says the National Weather Service (NWS). Check out this handy chart from NWS to see how long you can stay outside before frostbite becomes a serious concern.

Avoid alcohol. The Mayo Clinic says alcohol causes your body to lose heat faster, so plan to partake in that Irish coffee or après-ski cocktails after you get back inside for the day.

Keep moving. Exercise keeps your blood flowing, which keeps your body warm. But don't do it to the point of exhaustion, as that will hinder you getting to an emergency room should frostbite set in.