Cold urticaria is a rare but potentially life-threatening condition in which exposure to cold triggers an abnormal immune response, leading to hives, swelling, pain, and, in some cases, anaphylaxis. First described in 1792 by Johann Peter Frank, it affects about six in 10,000 people, is nearly twice as common in women, and often begins in early adulthood. The condition involves mast cells releasing histamine, which widens and leaks blood vessels, producing redness, itching, and swelling even though there is no real threat. About 95% of cases are primary with no clear cause, while secondary cases are linked to underlying illnesses or infections.
Triggers include cold weather, water, food, drinks, or objects, and symptoms can appear during rewarming. Diagnosis is usually made with supervised cold exposure tests, as serious reactions can occur. Management focuses on avoiding triggers, using antihistamines, sometimes at higher doses, and in more severe cases, other medications, desensitization, or emergency adrenaline for anaphylaxis. Although the disorder can be dangerous, especially during activities like swimming or medical procedures, many people improve over time, and up to half may partially or fully recover.