Unusual redness on the skin or mucus membranes caused by inflammation. Further descriptors can be used in diagnoses; for example, the rash characteristic of Lyme disease is an expanding oval, sometimes with a bull’s eye in the middle, called Erythema migrans.The term derives from the Greek word for “red,” erythros. Some doctors have debated the use of the term, because the color of inflamed skin is not always red, and so it can be inaccurate and confusing.
