What is the characteristic appearance of a wheal on the skin?

A wheal is a raised, often itchy area of skin that typically occurs as a result of an allergic reaction or other irritants. The hallmark appearance of a wheal is that it presents with a smooth elevation, which usually features red edges indicating inflammation, surrounding a paler, often white or skin-colored center. This gives the wheal its distinctive "smooth with red edges and white center" appearance, effectively signaling an allergic response or local irritation. Understanding the appearance of a wheal is crucial for recognizing allergic reactions and other dermatological conditions, emphasizing the body's response to certain stimuli.