Fire ants

Fire ant venom contains a chemical called piperidine.

Fire ants build dirt nests that form mounds, usually in open, grassy settings. They are typically found in the southern United States and other areas that do not freeze in winter.

Symptoms of a fire ant sting may include:

• Swelling, redness, itchiness, and pain around the site of the bite
• Pus-filled blisters that last 3 to 8 days
• Possible scab at the area of the bite that lasts 3 to 10 days

Those allergic to fire ant venom may also have:

• Difficulty breathing
• Rapid heart rate
• Throat swelling

Multiple fire ant stings may cause vomiting, diarrhea, swelling throughout the body, shortness of breath, low blood pressure, rapid heartbeat, and shock.

Home treatment depends on the location of, and reaction to, the sting.

Wash the exposed area with plenty of soap and water. DO NOT use alcohol to wash the area. Wash the eyes with plenty of water if any venom gets in them.

For mild stings, place ice (wrapped in a clean cloth) on the bite area for 10 minutes and then off for 10 minutes. Repeat this process. If the person has problems with blood circulation, decrease the time to prevent possible damage to the skin.

Some people are allergic to fire ant venom. If the reaction is severe, seek medical help right away and call your local emergency number (such as 911) or poison control.

Those who have an allergy to insect bites or stings should carry a bee sting kit and know how to use it in an emergency. These kits require a prescription.

Have this information ready:

• Person's age, weight, and condition
• The type of insect, if possible
• Time of the bite

Your local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. This national hotline will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

The health care provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. The wound will be treated as appropriate.

The person may receive:

• Blood and urine tests
• Breathing support, including oxygen (severe allergic reactions may require a tube down the throat and breathing machine)
• ECG (electrocardiogram, or heart tracing)
• Intravenous fluids (IV, through a vein)
• Medicines to treat symptoms

The sooner appropriate treatment is started, the better the outcome. People who are not allergic to fire ants should be fine in a few hours to a few days. People with severe allergic reactions may need to stay in the hospital.

Buttaravoli PM, Leffler S, Herrington RR. Fire ant stings. In: Buttaravoli PM, Leffler S, Herrington RR, eds. Minor Emergencies. 4th ed. Philadelphia, PA: Elsevier; 2022:chap 169.

Elston DM. Bites and stings. In: Bolognia JL, Schaffer JV, Cerroni L, eds. Dermatology. 4th ed. Philadelphia, PA: Elsevier; 2018:chap 85.

Erickson TB, Márquez A. Arthropod envenomation and parasitism. In: Auerbach PS, Cushing TA, Harris NS, eds. Auerbach's Wilderness Medicine. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 41.

Curtis AM, Erickson TB. Venomous animal injuries. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 53.

Updated by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.