What does the term 'wheal' refer to in dermatology?

In dermatology, the term 'wheal' specifically describes a round, localized area of edema on the skin. This is often a raised, itchy area that can occur as a result of an allergic reaction, insect bite, or other irritants. Wheals are characterized by their transient nature, meaning they can appear and disappear relatively quickly.

The formation of a wheal is due to the release of histamines and other chemicals that cause blood vessels to leak, leading to localized swelling. This aligns with conditions such as urticaria (hives), where wheals are a primary symptom. Understanding what a wheal is helps in recognizing and diagnosing various skin conditions and allergic responses.