Definition
- A patch is a flat, circumscribed skin discoloration that is > 1 cm in diameter.
- A flat skin discoloration < 1 cm in diameter is a macule.
Notes
- If the lesion is raised (instead of flat), it is a patch.
- "Circumscribed" means that it is clearly delineated (set-off) from its surroundings (not that it is circular in shape).
- Macule: Freckles
- Patch: Port-wine stain