What is the condition called where blood vessels dilate causing redness in the skin?

The condition where blood vessels dilate, leading to redness in the skin, is known as erythema. This physiological response typically occurs as a result of increased blood flow to the superficial layers of the skin. Erythema can be triggered by various factors, such as inflammation, infection, allergic reactions, or exposure to heat and sunlight. The dilation of blood vessels allows more blood to reach the surface, which can produce the characteristic red appearance.

Hyperpigmentation refers to areas of skin that become darker than the surrounding skin due to an excess of melanin, while edema involves swelling caused by the accumulation of fluid in the tissues. Alopecia is the medical term for hair loss and does not pertain to changes in skin color. Each of these other conditions affects the skin in different ways but does not explain the phenomenon of increased redness caused specifically by blood vessel dilation.