Pernio, also known as chilblains, is a medical condition that results from prolonged exposure to cold temperatures. The condition typically affects the hands, feet, toes, and fingers, causing swelling, redness, and itchiness. Some synonyms for pernio include cold sores, frostnip, chill burns, and perniosis. These terms are often used interchangeably with pernio to describe the same medical condition. It is important to keep the affected areas warm and avoid further exposure to cold temperatures to prevent pernio from worsening. Various medications and topical creams can also be used to alleviate the symptoms of this condition.