Imported Fire Ants look very much like ordinary ants. They are between a tenth and a fourth of an inch in size with an array of many sizes within this range and reddish brown to black in color. Imported Fire Ants are very aggressive when disturbed and cause a painful sting that produces a small white pustule about 8-24 hours following the sting.
Fire ant colonies build mounds that may be 10 inches or more in height, 15 inches or more in diameter, and 3 feet or more in depth.
The red imported fire ant, Solenopsis invicta Buren, the black imported fire ant, Solenopsis richteri Forel, and their hybrid are nuisance insects and their stings can cause serious medical problems. Imported fire ants interfere with outdoor activities and harm wildlife throughout the southern United States. Ant mounds are unsightly and may reduce land values. In some cases, imported fire ants are considered to be beneficial because they prey upon other arthropod pests. In urban areas, fire ants prey on flea larvae, chinch bugs, cockroach eggs, ticks and other pests. In many infested areas, the problems outweigh the benefits and controlling fire ants is highly desirable
Treatment
The first treatment for fire ant stings is to thouroughly wash the area. You can then apply a topical steroid cream, such as hydrocortisone, with a concentration of at least 0.25 percent. You can also administer oral antihistamines.Then you need to carefully monitor for allergic reactions or infection, either of which will require immediate medical attention.
Links
http://fireants.utk.edu/Webpages/ImpactPage.htm#medicalimpact