Fire Ant Bites Treatment & Management

Local stings

Cool compresses and oral antihistamines are recommended for mild reactions. Corticosteroids can be used topically or intralesionally for anti-inflammatory effect.

Multiple stings

Systemic corticosteroid use is controversial in patients with extensive lesions who do not have systemic allergic reactions or generalized skin reactions. Large doses of corticosteroids and intravenous fluids may complicate the treatment of patients with preexisting cardiovascular disease. The immunosuppressive effect of corticosteroids may predispose patients to secondary infection.

Oral antihistamines and topical corticosteroids are recommended in most cases; nevertheless, some practitioners still use prednisone or other systemic steroids to treat patients with numerous lesions.

Anaphylaxis

Acute management of fire ant anaphylaxis is identical to treatment of anaphylaxis from other causes. Intramuscular epinephrine is used and repeated as needed to reverse the symptoms. Epinephrine administration can also be followed by steroids, antihistamines, and H2 blockers. ^[13]

Further outpatient medications

Desensitization may be helpful to protect patients who are allergic from reactions to future stings. This type of immunotherapy has been used for almost 30 years to prevent the recurrence of anaphylaxis. ^{[14, 15]}

Treatment consists of weekly subcutaneous injections of increasing doses of whole-body vaccine until a predetermined maintenance dose is reached (usually 0.5 mL of a 1:10 dilution of the 1:10 weight/volume stock whole-body vaccine solution). Maintenance doses are typically administered every 4-6 weeks.

Immunotherapy for children with isolated skin reactions to fire ant stings is controversial because of a lack of data. ^[16] Most allergists do not routinely recommend immunotherapy for this population, but some do because of the great risk of stings in endemic areas.

Prescribe an anaphylactic kit (ANA kit) or Epi-Pen, if indicated. ^[16]

An allergist/immunologist consultation for evaluation and possible skin or in vitro testing for fire ant hypersensitivity is appropriate for any patient who has a systemic reaction to a fire ant sting. ^[17] Consultation should be considered if the patient meets 1 of the following criteria:

• Experiences anaphylaxis with a fire ant sting as a possible cause

• Needs education regarding fire ant avoidance or emergency treatment

• May need venom immunotherapy

• Has a coexisting condition that may complicate treatment of anaphylaxis (eg, using beta-blockers, having hypertension or cardiac arrhythmias)

No dietary changes are recommended; however, patients should have nothing by mouth if experiencing a severe systemic reaction.

No restriction in activity is required; however, rest is recommended in severe cases to possibly slow the spread of the reaction.

Avoidance of fire ants is important in the management of patients with fire ant hypersensitivity. Avoidance is facilitated by the following:

• Having professionals evaluate the patient's home for stinging insect nests and fire ant mounds, and, if found, exterminating these nests and mounds

• Not wearing brightly colored clothing or strongly scented lotions

• Wearing shoes (not sandals) when walking outside

• Being cautious around bushes, attics, picnic areas, or garbage containers

• Keeping insecticides readily available

• Wearing long pants, a long-sleeved shirt, socks, shoes, a hat, and work gloves when working outside

Attempts to control fire ant populations in endemic areas have included the use of chemical pesticides and novel biological control, including the use of decapitating flies. Decapitating flies (ie, Pseudacteon tricuspis, Pseudacteon curvatus, Pseudacteon littoralis) from South America have been released in the United States. These flies deposit an egg in the thorax of worker fire ants. The egg hatches and the larvae move toward the head, where they eat the ant's glands and muscles and release an enzyme that makes the ant's head fall off. ^[18]