Chilblains (perniosis, also known as pernio) is a reaction to cold, nonfreezing temperatures. It is seen most often in young people who have Raynaud's phenomenon and people who are exposed to damp, cold weather.
Symptoms develop 2 to 14 hours after exposure to cold and usually affect the hands, ears, lower legs, or feet. Symptoms include:
Local redness and swelling.
Changes in sensation, such as itching or burning.
Tender blue bumps that develop after rewarming.
Blisters and ulcers (in severe cases).
Treatment includes rewarming the affected areas, caring for any blisters that form, and avoiding reexposure to cold.