Bald-faced hornet sting
A bald-faced hornet sting usually shows up as a large, hot, red swelling with a central point, red, appearing immediate severe pain. It peaks around 2 to 24 hours and generally lasts swelling for several days. Often several — the colony defends aggressively is the usual arrangement.
| Looks like | a large, hot, red swelling with a central point |
|---|---|
| Pattern | often several — the colony defends aggressively |
| Size | 15–120 mm |
| Appears | immediate severe pain |
| Worst at | 2 to 24 hours |
| Lasts | swelling for several days |
| Itch | ●●●○○ 3/5 |
| Pain | ●●●●● 5/5 |
| Usually on | head, neck, arms |
| Active | June to October, daytime |
How to tell it apart
Technically a large yellowjacket, black with an ivory-white face, and the most defensive of the group. Multiple stings during a single encounter are typical because the colony responds together and follows for a distance.
Where and when you meet it
Habitat: enclosed grey paper nests the size of a football, hanging in trees, on sheds and under eaves.
Across 33,623 verified US records in the GBIF biodiversity database, sightings of Dolichovespula maculata concentrate in July to October. 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
- New York 3,149 records
- Illinois 3,047 records
- Minnesota 2,698 records
- Ohio 2,268 records
- Pennsylvania 2,180 records
- Massachusetts 1,834 records
- Virginia 1,617 records
- Maryland 1,463 records
- Washington 1,243 records
- Michigan 1,108 records
- New Jersey 1,070 records
- North Carolina 1,045 records
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
| Country | Records | Peak months there |
|---|---|---|
| United States | 33,623 | July to October |
| Canada | 11,312 | July to September |
| Germany | 19 | — |
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
Nests are annual and die off with the first hard frost, so removal is only urgent where people pass close by. Provocation from mowing or strimming under a tree is the usual trigger for a mass-sting incident.
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.
- breathing difficulty, throat tightness, faintness, hives away from the site
- multiple stings
- stings to the face or mouth
Care at home
- leave the area quickly — this species pursues
- cold pack, antihistamine, pain relief
- adrenaline auto-injector if prescribed
Preventing the next one
- never disturb an enclosed grey paper nest; have it removed professionally
- keep distance when mowing or strimming near trees
Common questions
How do I know it was a bald-faced hornet?
Technically a large yellowjacket, black with an ivory-white face, and the most defensive of the group. Multiple stings during a single encounter are typical because the colony responds together and follows for a distance.
How long does a bald-faced hornet sting last?
Typically swelling for several days, peaking around 2 to 24 hours.
When is it a problem?
Seek care for: breathing difficulty, throat tightness, faintness, hives away from the site; multiple stings; stings to the face or mouth.
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
Everything above is free to read. The app adds what a page cannot: point your camera at the bite and get an assessment of the most likely cause, a severity read, and a day-by-day care plan — including the specific signs that mean you should be seen.
iPhone and iPad. Free to download.