Brown recluse spider bite
A brown recluse spider bite usually shows up as a red bump that may develop a pale or blue-grey centre and, in a minority of cases, an ulcer, red rim, dusky centre, appearing often painless at first. It peaks around pain and colour change over 24 to 72 hours and generally lasts most heal in weeks; a true necrotic lesion can take months. Single site is the usual arrangement.
| Looks like | a red bump that may develop a pale or blue-grey centre and, in a minority of cases, an ulcer |
|---|---|
| Pattern | single site |
| Size | 5–50 mm |
| Appears | often painless at first |
| Worst at | pain and colour change over 24 to 72 hours |
| Lasts | most heal in weeks; a true necrotic lesion can take months |
| Itch | ●●○○○ 2/5 |
| Pain | ●●●●○ 4/5 |
| Usually on | torso under clothing, upper arms, thighs — often where clothing was put on with the spider inside |
| Active | April to October, night |
How to tell it apart
Genuine brown recluse bites are far rarer than the diagnosis. The spider is uniformly tan with a darker violin-shaped mark behind the eyes and lives in a limited geographic range — roughly Kansas to Texas and east to Georgia. Outside that range a "recluse bite" is almost always something else.
Where and when you meet it
Habitat: undisturbed storage — boxes, wardrobes, behind furniture — in the south-central states.
Across 6,240 verified US records in the GBIF biodiversity database, sightings of Loxosceles reclusa concentrate in May to August. 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
- Texas 1,150 records
- Missouri 1,018 records
- Oklahoma 753 records
- Illinois 563 records
- Tennessee 563 records
- Kansas 557 records
- Arkansas 490 records
- Alabama 247 records
- Kentucky 246 records
- Indiana 183 records
- Mississippi 132 records
- Georgia 72 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 | 6,240 | May to August |
| Germany | 1 | — |
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
The most common thing mistaken for a recluse bite is a staph skin infection, which spreads faster, hurts more and needs antibiotics rather than wound care. That distinction matters more than identifying the spider: an expanding, hot, painful area with fever is a reason to be seen quickly regardless of what caused it.
Seek medical care if
- a wound that darkens, blisters or breaks down over days
- fever, chills or widespread rash
- rapidly spreading redness and pain — more often a bacterial infection than a spider
Care at home
- wash, cold pack, elevate the limb
- have a changing lesion assessed rather than treated at home
- do not apply heat, and do not let anyone cut the lesion out early
Preventing the next one
- shake out clothing and bedding stored in the garage or loft
- gloves when handling boxes
- reduce cardboard clutter
Common questions
How do I know it was a brown recluse spider?
Genuine brown recluse bites are far rarer than the diagnosis. The spider is uniformly tan with a darker violin-shaped mark behind the eyes and lives in a limited geographic range — roughly Kansas to Texas and east to Georgia. Outside that range a "recluse bite" is almost always something else.
How long does a brown recluse spider bite last?
Typically most heal in weeks; a true necrotic lesion can take months, peaking around pain and colour change over 24 to 72 hours.
When is it a problem?
Seek care for: a wound that darkens, blisters or breaks down over days; fever, chills or widespread rash; rapidly spreading redness and pain — more often a bacterial infection than a spider.
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.