Not all wheals are alike. They may be redder or paler than the skin around them. They may vary in configuration and may be rounded or flat-topped. Wheals typically have a reddish hue. They characteristically change in size and shape and they come and go. But they are consistent at being smooth and elevated above the surrounding skin. As anyone who has had wheals knows, they can be intensely, infuriatingly itchy.
Wheals reflect circumscribed dermal edema (fluid collection in the layer of skin below the surface).
A wheal is also sometimes called a welt and often a hive.