A patch is defined as which of the following?

• A. A flat nonpalpable spot less than 10 mm
• B. A macule greater than 10 mm
• C. A solid palpable lesion less than 5 mm
• D. A raised plaque with scale

Answer: (B)

In dermatology, the difference between macules and patches is based on flatness, color change, and size. A patch is a flat, nonpalpable area of color change that is larger than 1 centimeter in diameter. Describing the lesion as a macule that is greater than 10 mm fits this definition, because it is flat and exceeds 1 cm, thus aligning with the patch category. The other options describe features that don’t fit a patch: a small flat color change is a macule but under 1 cm; a solid palpable lesion under 5 mm is a papule; a raised plaque with scale is a plaque.