Fire Ants Pose Health Hazard for People With Allergies, Experts Say

The fire ant invasion that has reached Southern California could pose a health hazard for some people who may suffer severe allergic reactions or even death from an ant’s sting, experts say.

At least 40 people die in the United States each year from all kinds of insect sting anaphylaxis, according to allergy specialists. It is estimated that half the deaths are from fire ant stings, said Dr. Chester Stafford, a nationally recognized allergy expert at the Medical College of Georgia in Augusta.

The most severe cases occur in people who develop allergies to an insect’s venom. They become sensitized to the venom through a previous sting, medical experts said.

In such repeat exposures, those who are allergic to ant venom may experience swelling of the larynx and tongue and, in the cases of full-blown anaphylaxis, dizziness, a drop in blood pressure and unconsciousness.

“Avoidance is the most important thing. People should wear clothing over their legs and arms when they are potentially going to be in contact with ants,” said Dr. Donald Levy, a board certified allergist in Orange. “People don’t have to be worried about having a severe reaction the first time they are stung.”

The vast majority of fatalities occur in Texas and Florida. Severe allergic reactions occur in about 1 in 10,000 cases, according to Michael Merchant, an expert at Texas A & M.

More common than a severe reaction to the allergens is a localized swelling around the sting, which is caused by irritation from toxins in the venom, said experts.

The ant is endemic in 13 Southern states. Infestations in Orange and Los Angeles counties were recently discovered.

The fire ant has a particularized stinging method. It first bites its victim with its mandible (or teeth), then arches its body to inject venom with the stinger at its distal end. The ant stings repeatedly, said Stafford.

In the South, the insect “has become a significant health hazard and may be the No. 1 agent of insect stings,” according to the American College of Allergy, Asthma and Immunology.

A severe reaction is characterized by extreme swelling at the sting site or elsewhere and can include facial flushing or swelling, generalized hives, swelling of the eyes or throat, wheezing or difficulty breathing.

About half of the deaths are due to swelling of the larynx, although other systemic reactions, including shock, can also be fatal, said Stafford. “Any throat constriction or change in voice or hoarseness is a serious sign,” he said.

Those with known sensitivity to the venom should carry epinephrine or an emergency anti-venom kit. In case of stings, the drug should be administered along with antihistamines and immediate attention by a physician, according to the American College of Asthma, Allergy and Immunology.

Allergists recommend immunotherapy for people who have a demonstrated sensitivity to the ant venom. It involves a series of injections to build up tolerance to the venom’s allergens. “Such treatment is 97% effective,” said Stafford.