Know how to use "fewer" and "less"? Find out.
medical Latin, from Greek erithema, from erythainein "to become red," from erythros "red" (see red (1)). Related: Erythematous.
erythema er·y·the·ma (ěr'ə-thē'mə)n. Redness of the skin caused by dilatation and congestion of the capillaries, often a sign of inflammation or infection.