What causes hives?

Mast Cells: A special type of white blood cell (bodily defense system) called a mast cell contains the chemical histamine. When it is released in the and around the skin it causes the local swelling and itching we call hives or urticaria. This release of histamine can be caused by lots things like allergies, cold, exercise and even exposure to sunlight.

Broad answer: The causes of hives is very broad: foods, medications, other medical conditions to name a few. A detailed history is required to elucidate the cause of hives. It is not unusual to not find a cause of hives.

Many causes: There are many causes of hives and these include infections, medications, bee/wasp stings, food allergies, environmental allergies, stress, cold temperatures, and exercise amongst other rarer causes. Oftentimes, hives are idiopathic, meaning there is no known cause. For further evaluation and management, consultation with a board-certified allergist is recommended for evaluation and management.