Causes
It can be caused by infection, massage, electrical treatment, acne medication, allergies, exercise, solar radiation (sunburn), cutaneous radiation syndrome, niacin administration, or waxing and tweezing of the hairs—any of which can cause the capillaries to dilate, resulting in redness. Erythema is a common side effect of radiotherapy treatment due to patient exposure to ionizing radiation.
In about 30–50% of cases, the cause of erythema is unknown.
Circumoral erythema has been described as a typical sign of acute oleander poisoning by ingestion.
May also be caused by Vitamin A toxicity.
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