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Hives Skin Pictures
Hives are pale red swellings of skin that occur in groups on any part of the
skin. It is triggered by an allergic reaction causing histamine to be release
into the body.
Hives are formed by blood plasma leaking out of small blood vessels in the skin. This is
caused by the release of a chemical called histamine. Histamine is released from cells
called "mast cells" that lie along the blood vessels in the skin. Allergic
reactions, chemicals in foods, or medications can cause histamine release. Sometimes it's
impossible to find out why hives are forming.