Erythema, redness due to sunburn, is a visible sign of skin damage caused by overexposure to the sun's ultraviolet rays The amount of sunlight needed to cause minimally perceptible sunburn is known as the minimal erythema dose (MED)
In medicine, this term is applied to redness of the skin due to blood vessel distension
A disease of the skin, in which a diffused inflammation forms rose-colored patches of variable size