Sunday, August 19, 2007

Fire Ant Bites

My neighbor asked me what the best way to treat her fire ant bites is. First some information on fire ants. (photo credit)

The fire ant is a wingless member of the order Hymenoptera, which includes wasps and bees. Fire ants are thought to have arrived in the United States between 1918 and the 1930s from South America by ships that docked in Mobile, Alabama. They are now found throughout the Southeast and are migrating rapidly. It is important to recognize and avoid the ant mounds.

The fire ant's attack is a two-part process consisting of a bite and a sting. The fire ant uses its mandibles to grasp its victim (bite). It then arches its body and drives an abdominal stinger into the skin to release the venom (sting). If the fire ant is not quickly removed, it will pivot around its mandibles and inflict further stings in a circular pattern. When the ant stings, it injects a venom that causes the release of histamine, a chemical in our bodies that can produce pain, itching, swelling and redness of the skin. Within seconds after the sting, discomfort occurs at the local site and a small red welt appears. The welt can enlarge rapidly, depending on the amount of venom that was injected and the victim's sensitivity to the venom. The reaction persists for up to an hour, and then a small blister that contains clear fluid will form. Over the next half day or so, the fluid in the blister turns cloudy (the sterile pustule), and the area begins to itch. The diameter of a sting wound is normally 2-4 mm. Most children experience only a small amount of redness around the sting site. A small percentage of people are sensitive to the venom and experience more extensive redness and swelling. Fortunately, only a very small number of victims have extensive allergic reactions such as breathing difficulties or widespread swelling of body parts.

For mild reactions:

  • Move away from the ant hill to a safe area to avoid more stings.
  • Scrape or brush off the stinger with a straight-edged object, such as a credit card. Wash the affected area with soap and water. Don't try to pull out the stinger; doing so may release more venom.
  • To reduce pain and swelling, apply a cold pack or cloth filled with ice.
  • Apply 0.5 percent or 1 percent hydrocortisone cream, calamine lotion or a baking soda paste (make with a ratio of 3 teaspoons baking soda to 1 teaspoon water ) to the bite or sting several times a day until your symptoms subside.
  • Take an antihistamine containing diphenhydramine (Benadryl, Tylenol Severe Allergy) or chlorpheniramine maleate (Chlor-Trimeton, Teldrin).

For severe reactions (anaphylaxis):

Severe reactions may progress rapidly. Dial 911 or call for emergency medical assistance if the following signs or symptoms occur:

  • Difficulty breathing
  • Swelling of your lips or throat
  • Faintness and/or Dizziness
  • Confusion
  • Rapid heartbeat
  • Hives or swelling more than 2 inches in diameter at the site
  • Nausea, cramps and vomiting

Take these actions immediately while waiting with an affected person for medical help:

    1. Check for special medications that the person might be carrying to treat an allergic attack (ie, EpiPen). Administer the drug as directed — usually by pressing the auto-injector against the person's thigh and holding it in place for several seconds. Massage the injection site for 10 seconds to enhance absorption.
    2. After administering epinephrine (or if no Epi available), have the person take an antihistamine pill (see above--Benedryl, etc) if he or she is able to do so without choking.
    3. Have the person lie still on his or her back with feet higher than the head.
    4. Loosen tight clothing and cover the person with a blanket. Don't give anything to drink.
    5. If there's vomiting or bleeding from the mouth, turn the person on his or her side to prevent choking.
    6. If there are no signs of circulation (breathing, coughing or movement), begin CPR.

If your doctor has prescribed an auto-injector of epinephrine, read the instructions before a problem develops and also have your household members read them.


References:
Fire Ants by James P Ralston, MD--eMedicine article
Insect Bites and Stings: First Aid--MayoClinic.com
Imported Fire Ants-FAQ--Univ of Texas at Austin
Diagnosing and Treating Animals for Red Imported Fire Ant Injury--Texas A & M University

1 comment:

Chrysalis Angel said...

That poor little hand in the photo. Those things are nasty.