Seal on the arm

A seal on the arm is a raised, circular, red rash that can range in size from a few millimeters to several centimeters. It usually starts as a small, flat, red spot that gradually enlarges over the course of several days, and may be accompanied by itching, burning, or pain. Eventually, the center of the rash will form a thick, raised area with a clear center that may look like a bull's-eye. It may become scaly or crusty, and may spread to other parts of the body.