A wheal or wheal response (also termed a welt) is a firm, elevated, rounded or flat topped,, generally pale red papule or plaque swellings of the skin. They are usually well demarcated and may be round, oval, gyrate, annular or irregular/serpiginous with pseudopods in shape. They often itch or have a burning sensation but are transient, typically disappearing within 24-48 hours.
An itchy rash consisting of wheals may be called a uticarial exanthem, or urticaria, and more commonly as hives.
While the borders are sharp, they are not stable, and as this short-lived papillary edema shifts, each wheal transiently moves from involved to adjacent uninvolved areas over a period of hours. Also note, while this finding is usually pale red, if the amount of edema is adequate to compress superficial vessels, the wheal may have a white center. The epidermis is not affected and there is no scaling.