Giant urticaria, commonly known as hives, is an enlarged and itchy skin rash. It might occur on only one body portion or cover a wide area in your body. The rash is often itchy and may vary in size from a few mm up to the size of a palm. Although the afflicted region may have varying looks over one day, the rash typically resolves within several days.
Furthermore, giant urticaria develops whenever a trigger promotes the production of large quantities of histamine and other chemical messengers into the skin. These compounds make blood vessels in the afflicted skin region dilate and leak.