Which skin condition is defined as having small, round, flat dark-red spots?

The skin condition described as having small, round, flat dark-red spots is indeed ecchymosis. Ecchymosis refers to the discoloration of the skin resulting from bleeding underneath, typically caused by trauma or injury to blood vessels. These dark-red spots are often recognized as bruises, appearing where blood has leaked into the surrounding tissue.

Unlike other options, ecchymosis is characterized specifically by its flatness and distinct coloration, which can vary from dark red to purple or blue as the bruise heals. This contrasts with other conditions like pustules, which are raised bumps filled with pus; wheals, which are raised, itchy areas (such as hives) typically caused by an allergic reaction; and bullae, which are large fluid-filled blisters. Each of these conditions presents differently than ecchymosis, both in terms of appearance and underlying cause. Understanding these distinctions is crucial for accurate identification and documentation in medical settings.