Hives is common in people with a history of allergies, but independent immune reactions can also trigger it. Its causes are complex, and may include food allergens, allergic reactions to drugs, psychogenic factors such as stress, changes in weather, and even drafts.
除了過敏之外，蕁麻疹與自體的免疫反應也有關係，致病機轉比較複雜，有可能是食物過敏或藥物過敏，也有神經性的──天氣變化或吹風引起，也可能是壓力等心理因素造成。