Mottling

Mottle or mottling was a medical term which was used to describe uneven discolored patched on humanoid skin, which could be caused by lowered blood pressure to that part of the skin or various infections.

Petechia also resembled a form of vacuum mottling. While examining Crewman Scott Darnell's body in 2266, Doctor Leonard McCoy explained the similarity to Captain James T. Kirk.