What characterizes the appearance of the wheals in urticaria?

Wheals in urticaria, commonly known as hives, are characterized by their pale and evanescent appearance. This means they are typically raised above the skin's surface and have a light color at the center, often surrounded by a red flare. The term "evanescent" reflects their transient nature; wheals can appear suddenly and may last for only a few hours before disappearing. This quick resolution is a hallmark of urticaria, making this description particularly accurate.

While other choices mention various characteristics, they do not capture the specific look and behavior of wheals in urticaria as accurately as the pale and evanescent description does. For instance, while wheals can sometimes be itchy, they are not generally described as painful, and the focus on color and edematous properties is missed in the options that mention other color descriptors or inflammatory states.