Skin redness, often caused by inflammation or infection.

• A. Erythema
• B. Gait
• C. Allergy
• D. Antigen

Answer: (A)

Redness of the skin caused by inflammation or infection is called erythema. This happens when signals from irritated tissue cause the small surface blood vessels to widen (vasodilation), bringing more blood to the area. The increased blood flow makes the skin appear red and often warm, and it can be accompanied by swelling. While redness can occur with allergic reactions or irritation, the specific term for the skin color change itself is erythema. The other terms describe related ideas but do not name the color change: one refers to how a person walks, another to a reaction that can involve redness but isn’t the redness itself, and the last is a substance that can trigger immune responses rather than the visible sign.