What is the key distinguishing factor between a macule and a patch?

The key distinguishing factor between a macule and a patch is indeed size. A macule is defined as a flat, circumscribed area of skin that is different in color from the surrounding skin and is typically less than 1 centimeter in diameter. In contrast, a patch is similar in nature but measures 1 centimeter or larger across. This distinction is commonly used in dermatology to categorize skin lesions based on their dimensions.

While configuration, disease state, and location can influence the interpretation and significance of these skin features, they do not serve as defining criteria for differentiating between a macule and a patch. The explicit focus on size establishes a clear and objective way to classify these lesions within clinical practice.