Damage to the basal layer of the epidermis triggers the body’s inflammatory response as part of the normal physiological
process of wound healing. This involves the release of histamine-like substances, capillary dilation and increased vascular permeability that result in skin redness and warmth. Patients may also experience sensations such as itching, discomfort and tightness. The words used to describe the severity of erythema range from faint and dull to bright and tender. In patients with darker/black skin the treatment field will appear a darker colour . Erythema may appear at doses of 2000cGy.