Which of the following best describes a macule?

A macule is defined as a flat, distinct, and discolored area of skin that measures less than 1 centimeter in diameter. This characteristic aligns perfectly with what is commonly seen with freckles, which are also small and flat. Macules do not have any texture or elevation; they are simply changes in color that can result from various factors such as sun exposure, pigmentation changes, or other dermatological conditions. Understanding that macules are not raised or palpable, but rather flat and small, is key to identifying them accurately in practice.

The other descriptions provided do not match the definition of a macule. For example, a smooth raised bump larger than 1 cm refers to a different type of lesion entirely, which could be a nodule or plaque. A patch of thickened skin larger than 1 cm typically describes a lesion like a plaque or another form of dermatitis. Persistent redness of the skin may indicate an underlying vascular issue or inflammation, which is not representative of a macule's defining characteristics. Thus, option B effectively encapsulates the essence of what a macule is within dermatology.