All ants can bite, but the ant that most often causes painful bites is the fire ant. After the initial, painful bite, secondary infection or allergic reactions may occur. Typically, fire ant bites produce an acute inflammation and ulceration around the affected area and tend to heal slowly.
You can go to controlfireants.com to see fire ant bites pictures. At controlfireants.com you can also find complete information about fire ants including treatment of stings and various ways to control fire ant.