Most bee stings cause irritation and inflammation of the skin. Sometimes, the venom can cause an allergic reaction.

Allergic reactions occur when the immune system overreacts to a harmless substance, called an allergen. The immune system is made up of special cells, called white blood cells, which fight infection. When an allergen is present in the body, white blood cells recognize the allergen, and release chemicals into the blood stream. These chemicals can cause inflammation of the skin, nose, throat, lungs or intestines.