Only about one half of one percent consists of other chemicals. These include a small amount of sodium chloride, urea, and lactic acid. Acute reactions occur during, or within weeks after radiation therapy, and usually involve basal cells, mucous membrane cells, and hematpoietic stem cells. Skin reactions usually fall into this category. Late responding reactions are those that are manifested months to years after radiation therapy is completed.
Late changes can follow acute changes.
It should be stressed to the patient that with megavoltage equipment and modern techniques, permanent skin changes usually are minimal. Erythema and Folliculitis Erythema should be categorized as mild, moderate, or severe. Mild erythema constitutes the first appearance of pink to the skin. Progression to a red hue is considered moderate erythema. In severe erythema, the skin is deep and dusky red.