What is the term for flat areas of skin that differ in color from the surrounding area?

The term for flat areas of skin that differ in color from the surrounding area is "macules." Macules are defined as small, flat, discolored spots on the skin that are often brown, red, or white, and do not change the texture of the skin. They are generally less than 1 centimeter in diameter and can occur in various conditions, such as freckles, certain types of dermatitis, or other skin lesions.

In contrast, vesicles are small fluid-filled blisters, which are raised and different in character compared to macules. Wheals are raised, itchy areas of skin that can be transient and typically represent an allergic reaction or hives. Fissures refer to deep cracks or splits in the skin and are not simply a change in color. Understanding these distinctions helps in identifying and describing various skin conditions accurately.