Circular Skin Rash on Arm

by Erin
(NY)

Unknown Circular Skin Rash on Arm

Can anyone help me identify what this is on my arm? It is perfectly circular and about a size of a quarter. It appeared out of nowhere and it is all red. It does not itch but is tender to the touch. Can anyone tell me what it might be, such as a bite of some sort or allergic reaction to something, etc.


You can find more skin rash information at the diagnose my skin rash page.