Erythema is defined as abnormal redness on the surface of the skin usually caused by irritation or congestion of the capillaries.(noun)
Redness on the surface of your skin after your skin is infected is an example of erythema.
See erythema in Webster's New World College Dictionary
Origin: ModL < Gr erythēma < erythainein, to redden, blush < erythros, red
See erythema in American Heritage Dictionary 4
Origin: Greek eruthēma
Origin: , from eruthainein, to redden, be red
Origin: , from eruthros, red; see reudh- in Indo-European roots.
Learn more about erythema