A Growing Threat

It is believed that fire ants entered the United States via steamships bringing agricultural products from South America to Mobile, Alabama, in the 1930s. Once they were in the United States., northern frosts and western deserts proved effective barriers to widespread fire ant migration for many years. However, recent warm, wet weather conditions, including the El Niño weather system of 1998, seem to have helped the ants advance north and west. They now cover more than 260 million acres and pose a serious health risk to humans, wildlife, and domesticated animals.¹ Reactions to fire ant stings range from localized itching and swelling with pustule formation to severe, life-threatening anaphylaxis.

 
Avoiding Stings

The best way to avoid stings is to minimize contact with stinging insects. Simple steps that people can take to avoid attracting and provoking stinging insects when outdoors are:

• Refraining from wearing brightly colored clothing or sweet-smelling cosmetics
• Keeping food and garbage covered
• Wearing shoes to guard against stepping on insects
• Keeping the arms and legs covered during activities (such as gardening or hiking) that may expose them to stinging insects
• Refraining from swatting or crushing insects
• Steering clear of areas where insects have nested

Because stinging insects attack when their nests are threatened, people who find nests, hives, or fire ant mounds on their property may wish to consult a professional pest control expert to determine whether eradication of the nest or insects themselves is appropriate.

 
What to Do if Someone Is Stung

If someone is stung you should:

• Remove any stingers
• Check for signs of an allergic reaction
• Treat allergic reactions immediately

Remove any stingers
Stingers left behind by bees should be removed immediately to minimize the amount of insect venom the sting delivers. It is important to remove the stinger in a sweeping motion—as with the edge of a credit card—instead of using tweezers to pull it out. A sweeping motion is less likely to break the stinger or push remaining venom from the stinger into the sting site (which can happen if you squeeze the stinger or try to pull it out).

Check for signs of an allergic reaction
A normal response to an insect sting is swelling, pain, and redness around the site of the sting or bite. Typically, washing the sting site with soap and water, and then applying ice to reduce the swelling is sufficient to treat a local reaction. However, physicians may prescribe antihistamines or corticosteroids to ameliorate the discomfort if the swelling is pronounced or if the location of the sting makes it especially uncomfortable.

When a person is allergic to an insect sting, the reaction is typically much more widespread and may include anaphylactic symptoms such as:

• Itching and hives
• Swelling of the throat or tongue
• Difficulty breathing
• Dizziness
• Severe headache
• Stomach cramps
• Diarrhea
• Nausea
• A sharp drop in blood pressure
• Loss of consciousness

Treat allergic reactions immediately
If an allergic person is stung, emergency medical treatment should be sought at once. If the allergic patient has injectable epinephrine such as the EpiPen^® or EpiPen^® Jr epinephrine auto-injector at hand, it should also be administered immediately to reverse the potentially deadly symptoms of anaphylaxis. Prompt administration of epinephrine is important because even seemingly mild allergic reactions can escalate to deadly anaphylaxis in minutes.²

The side effects of epinephrine may include palpitations, tachycardia sweating, nausea and vomiting, and respiratory difficulty. Cardiac arrhythmias may follow the administration of epinephrine. Physicians should instruct their patients about the circumstances under which this life-saving medication should be used.

Many physicians also recommend that antihistamines such as diphenhydramine be administered to lessen the symptoms of an allergic reaction, but antihistamines should be taken only in addition to epinephrine for the treatment of anaphylaxis and should not be considered a substitute for it. Only epinephrine can halt the potentially deadly effects of anaphylaxis.

Even when epinephrine is used, severely allergic people who have experienced anaphylaxis may need emergency respiratory or cardiac care, or even resuscitation if they stop breathing. In any case, when an allergic person is stung, he or she will need professional care to determine whether additional epinephrine, steroids, antihistamines, or other treatments are required. Follow-up diagnosis and care by medical professionals after the self-administration of epinephrine for insect stings may be critical to recovery.

Delayed or secondary reactions do occur, and patients should remain under medical supervision for at least 4 hours after an episode of anaphylaxis.³ As many as 25% of people who experience an anaphylactic reaction will have a recurrence up to 48 hours after the initial reaction and will require further medical treatment, including additional epinephrine.^4-6 Therefore, it is essential that anyone who experiences anaphylaxis be equipped with enough self-injectable epinephrine to treat additional episodes if necessary, whether they are secondary reactions or result from future exposures to anaphylactic triggers.

 
References

1. AAAAI. Health hazards of imported fire ant stings. Available at: www.aaaai.org.
    
2. The Merck Manual. 16th ed. Merck Research Laboratories. 1992:331.
    
3. Wood RA. Anaphylaxis in children. Patient Care. 1997;31(13):161.
    
4. Stark BJ, Sullivan TJ. Biphasic and protracted anaphylaxis. J Allergy Clin Immunol. 1986;78:76.
    
5. Brazil E, MacNamara AF. "Not so immediate" hypersensitivity—the danger of biphasic anaphylactic reactions. J Accid Emerg Med. 1998;(4):252-253.
    
6. Korenblatt, et al. 1998 ACCP meeting abstract #234: a retrospective study of the administration of epinephrine for anaphylaxis indicating need for more than one dose.
    
7. Fact File on Anaphylaxis: Acute Allergic Reactions to Food, Medication, Insect Stings, Latex. Dey; 2000.