macule

A macule is a flat, circumscribed area of skin color that is distinct from surrounding skin and has no change in texture or elevation. In dermatology, a macule is a primary lesion that measures less than 1 centimeter in diameter; if the area is larger, it is termed a patch. Macules are nonpalpable and the surface texture remains normal.

Macules can be pigmented or nonpigmented. Pigmented macules include freckles (ephelides) and lentigines, as well as larger flat pigmented lesions such as café-au-lait spots. Hypopigmented macules are lightened areas due to decreased pigment, as seen in vitiligo or pityriasis alba. Inflammatory or vascular processes can also produce flat color changes, yielding nonpigmented or erythematous macules.

Clinical features vary with cause but typically include color differences relative to adjacent skin, with well-defined or diffuse borders. They may occur anywhere on the skin and can appear individually or in clusters. Some macules are benign and transient, while others may be associated with systemic conditions or require monitoring for changes in size, color, or shape.

Differential diagnosis includes distinguishing macules from papules (raised lesions) and patches (larger flat areas). Evaluation may involve history, examination of distribution and evolution, and, if indicated, dermoscopy or biopsy to assess for malignancy or other underlying conditions.

Etymology: the term macule derives from the Latin macula, meaning spot.