How does erythema abigne occur?

Erythema abigne is a skin reaction to thermal injury. Chronic heating pad use is a common cause of this disorder. Usually, the affected area has a netlike pattern of blue-gray discoloration, sometimes with associated erythema and scale. Patients often complain that the affected area burns, stings, or itches. Treatment requires discontinuing heating pad use. Skin dyspigmentation slowly resolves over several months to a year, although permanent dermal scarring and hyperpigmentation can result.