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Fire ant sting

What it looks like: A burning red welt that develops a sterile white pustule within a day, red base, white or yellow pustule centre. Pattern: multiple stings in a ring or cluster — the ant grips and pivots. Onset: immediate burning. Worst at: pustule at 24 hours. Duration: pustule 3 to 10 days, mark can persist for weeks.

Fire ant (Solenopsis invicta), the insect that causes a fire ant sting
The insect, not the bite. Fire ant (Solenopsis invicta), photographed in United States of America in 2026. Photo by Jason Leduc, CC0 1.0, via GBIF.
At a glance — Solenopsis invicta
Looks likea burning red welt that develops a sterile white pustule within a day
Patternmultiple stings in a ring or cluster — the ant grips and pivots
Size2–10 mm
Appearsimmediate burning
Worst atpustule at 24 hours
Lastspustule 3 to 10 days, mark can persist for weeks
Itch●●●●○ 4/5
Pain●●●●○ 4/5
Usually onfeet, ankles, lower legs, hands
ActiveMarch to November, daytime, especially after rain when mounds are rebuilt

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How to tell it apart

Fire ants sting rather than bite: they anchor with their jaws and sting repeatedly in an arc, which produces a curved group of welts rather than a single mark. The sterile pustule that appears the next day is close to unique among American stinging insects and is the most reliable identifier.

Where and when you meet it

Habitat: open sunny ground — lawns, parks, roadsides and pasture across the Southeast and parts of the Southwest.

Across 24,771 verified US records in the GBIF biodiversity database, sightings of Solenopsis invicta concentrate in March to May. That is the window when bites are most likely — it is observation data rather than a guess, and it shifts with latitude.

States with the most recorded sightings

Record counts reflect where people report and identify specimens, not exact abundance. They are useful for ruling a species in, not for ruling it out.

Where it is recorded

CountryRecordsPeak months there
United States 24,771 March to May
Brazil 605 October
Australia 311 May, July

Verified records from the GBIF biodiversity database across the seven countries we cover. A country missing from this table means we have no records for it, not that the species is absent.

What it means for you

A whole colony responds at once, so a few seconds standing on a mound produces dozens of stings — which is why the reaction can look alarming even in someone not allergic. The medical concern is anaphylaxis in sensitised people, and anyone who has had a severe reaction should carry an adrenaline auto-injector.

Seek medical care if

Call emergency services now for difficulty breathing, swelling of the lips, tongue or throat, dizziness or fainting, or hives spreading away from the bite.

  • difficulty breathing, throat tightness, dizziness or hives away from the sting site — call emergency services
  • a previous severe reaction to any sting
  • stings covering a large area, particularly in a small child

Care at home

  1. move away from the mound and brush ants off — do not stand still
  2. wash and apply a cold pack
  3. leave the pustule intact; breaking it invites infection
  4. antihistamine for itch

Preventing the next one

  • look before standing or sitting on grass in fire ant country
  • closed shoes outdoors
  • treat mounds in the garden rather than kicking them

Common questions

Do fire ants sting humans?

Fire ants sting rather than bite: they anchor with their jaws and sting repeatedly in an arc, which produces a curved group of welts rather than a single mark. The sterile pustule that appears the next day is close to unique among American stinging insects and is the most reliable identifier.

What does a fire ant sting look like?

A burning red welt that develops a sterile white pustule within a day, red base, white or yellow pustule centre. Pattern: multiple stings in a ring or cluster — the ant grips and pivots. Size: typically 2–10 mm across.

Does a fire ant sting hurt?

Pain is severe (4 out of 5 on this site's scale) and itch is strong itch (4 out of 5). Onset: immediate burning. Worst at: pustule at 24 hours. Duration: pustule 3 to 10 days, mark can persist for weeks.

How do I know it was a fire ant?

Fire ants sting rather than bite: they anchor with their jaws and sting repeatedly in an arc, which produces a curved group of welts rather than a single mark. The sterile pustule that appears the next day is close to unique among American stinging insects and is the most reliable identifier.

How long does a fire ant sting last?

Duration: pustule 3 to 10 days, mark can persist for weeks. Worst at: pustule at 24 hours.

When is it a problem?

Seek care for: difficulty breathing, throat tightness, dizziness or hives away from the sting site — call emergency services; a previous severe reaction to any sting; stings covering a large area, particularly in a small child.

Can it transmit disease?

No human disease is known to be transmitted by this species in the United States. The practical risk is infection from scratching.

Get a photo assessment in the app

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