erythema

Redness of the skin or mucous membranes, caused by hyperemia (increased blood flow), dilation of superficial capillaries.
The skin rash by inflamed blood capillaries occurs in response to any skin injury, infection, or a drug. The severity ranges from mild to life threatening.

Causes:
- massage, exercise, tweezing
- electrical treatment
- photosensitization, sunburn, acute radiation syndrome
- allergies
- viral / bacterial infection
- mercury toxicity, niacin administration