Bald-faced hornet bites in Pennsylvania
Pennsylvania has 2,180 verified bald-faced hornet records in the GBIF biodiversity database — one of the highest counts in the country. Sightings concentrate in July to October. The bite itself appears immediate severe pain and lasts swelling for several days.
| Verified records | 2,180 |
|---|---|
| Peak sightings | July to October |
| State bite season | April to October |
| Active | daytime |
| Habitat | enclosed grey paper nests the size of a football, hanging in trees, on sheds and under eaves |
| Bite appears | immediate severe pain |
Identifying it in Pennsylvania
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.
Locally, the species most often confused with it are honey bee sting, carpenter ant bite, american dog tick bite — all of which are also recorded in Pennsylvania.
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
What else it could be in Pennsylvania
These are recorded in Pennsylvania too and are the ones most often confused with it here. The differences below are the ones that actually separate them.
| Bald-faced hornet sting | Paper wasp sting | Yellowjacket sting | |
|---|---|---|---|
| Pattern | often several — the colony defends aggressively | usually single | single or several — this wasp can sting repeatedly |
| Where on body | head, neck, arms | hands, head, arms — often while gardening or opening a shutter | hands, face, neck |
| Appears | immediate severe pain | immediate sharp pain | immediate sharp pain |
| Records here | 2,180 | 1,294 | 814 |
Season in Pennsylvania specifically
Records in Pennsylvania concentrate in July to October, which is what local sighting data shows rather than a national average — seasonality shifts substantially with latitude. The general bite season in Pennsylvania runs April to October.
Because enclosed grey paper nests the size of a football, hanging in trees, on sheds and under eaves, exposure in Pennsylvania tends to be concentrated in specific places rather than spread evenly — which is why a bite history ("where were you in the 24 hours before?") narrows the answer faster than the appearance of the mark.
Care
- leave the area quickly — this species pursues
- cold pack, antihistamine, pain relief
- adrenaline auto-injector if prescribed
Avoiding them in Pennsylvania
- never disturb an enclosed grey paper nest; have it removed professionally
- keep distance when mowing or strimming near trees
Questions
When are bald-faced hornets active in Pennsylvania?
Pennsylvania records peak in July to October. The general bite season in Pennsylvania runs April to October.
Are they common in Pennsylvania?
Pennsylvania accounts for 2,180 verified records in GBIF, ranking it 5th among states for this species. Records reflect reporting effort as well as abundance.
What does the bite look like?
a large, hot, red swelling with a central point, red. Often several — the colony defends aggressively.
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.