The burning facts about fire ants

Everywhere around us we see visible signs of summer.

Children are playing on sports fields and playgrounds. Adults are diligently mowing lawns and landscaping flower beds. It is one of the most magical times of the year.

Except … for the tiny "friends" with which we share our lawn and fields.

One of those tiny creatures we frequently encounter is the fire ant. While often considered just a pesky insect, the fire ant can actually be the cause of life-threatening reactions in certain individuals.

The imported fire ant (Solenopsis invicta) is not native to the United States. They were accidentally "imported" from South America around the 1930s. Since then, the range of the fire ant has expanded throughout most of the southern United States. They also continue to spread north and have been found as far north as Virginia. The temperate climate of Northeast Florida makes for an excellent home for these insects.

Fire ants build their colonies in dome-shaped mounds of soil that can reach 3 feet across and up to 18 inches in height. A well-established colony may contain as many as 500,000 ants. Their sheer abundance makes it very difficult for us to avoid.

Fire ants will attack anything that disturbs them without warning. Recent data suggests that up to 89 percent of all people in ant-infested areas may be stung each year.

Contrary to popular belief, fire ants produce their venomous reactions by stinging, not biting. The fire ant uses its very strong jaws to latch onto the skin and then uses its sharp stinger to inject venom.

Unlike honeybees, fire ants can continue to sting a victim numerous times. In fact, a single ant stings an average of three times before removal. Stings are most common and most painful during the summer when ants have the largest amount of stored venom.

The most common reaction to a fire ant sting is intense itching and a burning sensation (fire-like) at the site of stings.

The sting leaves a raised red welt, which typically subsides within 30 to 60 minutes. Within 24 hours, "pimple-like" areas filled with pus will form. These sores rupture over two to three days and are accompanied with itching, pain and swelling. Fortunately, these reactions are self-limited and do not predispose to life-threatening reactions.

If stung, the area should then be washed with soap and cool water. Isolated local symptoms are managed with ice, anti-inflammatory medications, topical steroids and antihistamines. It is important to keep the area clean and not scratch or break the blisters.

Larger local reactions or those that continue to ooze may require medical evaluation. Medications, such as oral steroids or antibiotics, may be necessary.

Up to 16 percent of people stung by a fire ant may develop a diffuse allergic reaction, however, according to a Georgia study.

The most serious type of this reaction is anaphylaxis, a life-threatening allergic reaction. Within minutes to seconds after a sting, sensitive individuals may develop flushing, itching, swelling of the face and throat, difficulty breathing, or loss of consciousness. This is a true medical emergency and, if untreated, this reaction may be fatal.

Any person that develops difficulty swallowing, trouble breathing or fainting requires immediate medical treatment. The individual, a friend or a family member should immediately dial 911. If available, injectable epinephrine should be administered. This is the only true lifesaving treatment for anaphylaxis.

People with a history of diffuse allergic reactions or anaphylaxis should have an evaluation by a trained allergist. The affected person should wear a medical alert bracelet and always carry an epinephrine auto-injector.

Allergy testing may be performed and allergy injections may be given to help patients build up a tolerance to the venom over time. This significantly reduces the likelihood of a repeat reaction.

Control measures include avoidance and outdoor insecticide treatment. Those with previous reactions should be cognizant of their environment and be on the lookout for mounds or fire ant activity.

Fire ants will not sting through fabric. So, in areas of known infestation, consider wearing long pants, shoes, socks and long sleeves.

Insect repellents are not effective in preventing fire ant stings. Outdoor treatments such as specific pesticides, individual mound treatments, baits or barrier treatments may be used to control the spread of fire ants.

It might be best, however, to obtain the assistance of professional exterminating services.

While mostly just an annoyance, fire ant stings have the potential to be fatal. Unfortunately, avoidance is not always possible. Knowing the signs and symptoms of various types of allergic reactions is essential and may be lifesaving.

Patrick DeMarco is a board certified allergist and Immunologist with Allergy & Asthma Specialists of North Florida. He is a past president of the Florida Allergy, Asthma & Immunology Society and a member of the board of directors of the Duval County Medical Society.