Fire Ant Stings

Presentation

Usually the patient has experienced multiple burning stings (the so-called fire in the fire ant) and is seeking help because of local swelling, itching, and/or pain. Twenty-four hours after the initial wheal and flare at the sting site, there is formation of a small (2 mm), sterile, round pustule on an erythematous base, which is virtually pathognomonic for a fire ant sting ( Figs. 169.1 & 169.2 ). These lesions often occur in clusters. Sometimes there are large local reactions, and it is not unusual for an entire extremity to be affected. Systemic reactions in previously sensitized individuals are analogous to those caused by hymenopteran stings (see Chapter 173 ).

The appearance of the sting site changes over time. Within 1 week, the pustule often ruptures, forming a small crust or superficial ulcer, which then may become secondarily infected. After 1 month, small visible scars will be persistent.