Brown Recluse
See a doctorLoxosceles reclusa · also called fiddleback spider, violin spider
The brown recluse is genuinely capable of causing a serious wound, and it is also the single most over-reported spider in North America. Verified recluses are essentially absent from California, Florida, the Pacific Northwest and the entire northeast, yet 'brown recluse bites' are diagnosed in all of those places constantly. If you are outside the range map, the odds are overwhelming that you have something else.
If you think you were bitten
- Most suspected spider bites are not spider bites. Studies of patients presenting with a “spider bite” repeatedly find that the large majority are bacterial skin infections — frequently MRSA — which need antibiotics rather than reassurance. A spreading, painful, pus-filled sore is far more likely to be an infection than a spider.
- Wash it, ice it, and watch it. Clean the area with soap and water, apply a cold pack, and keep an eye on it.
- Get medical care if the wound spreads or darkens, if you develop cramping, sweating, fever or severe abdominal pain, or if you are confident it was a widow or a recluse.
- Bring the spider only if it is already dead and to hand. Do not go looking for it. Doctors treat symptoms, not species.
In the US, the Poison Help line is 1-800-222-1222. This site is a reference, not medical advice.
Quick facts
- Bite risk
- Venom can cause a slowly developing necrotic lesion in a minority of bites, though most produce nothing worse than local redness that resolves on its own. Seek medical assessment for a suspected bite, but be aware that spider bites are heavily over-diagnosed — many lesions attributed to recluses turn out to be bacterial infections, most often MRSA.
- Size
- Body 6–12 mm. Body about the size of a pea; legspan roughly a US quarter. Anything bigger than a silver dollar with legs out is not a recluse.
- Appearance
- Uniform light-to-medium brown with a darker violin-shaped mark on the head-and-thorax section, the neck of the violin pointing backwards. The legs are plain — no bands, no spines, no stripes — and covered in fine hairs rather than obvious bristles.
- Web
- Builds a small, irregular, sticky retreat web in undisturbed corners, never a neat orb or a funnel. The web is a hideout, not a trap.
- Found in
- indoors, basement, garage, woodpile
- Family
- Sicariidae
- Range
- 16 US states
How to identify a brown recluse
- Six eyes arranged in three pairs, not the usual eight. This is the only truly diagnostic feature and it needs a magnifier or a sharp photo.
- Uniformly coloured legs with no bands, spines or stripes.
- A single, even body colour — no spots, no chevrons, no patterning on the abdomen.
- The violin mark is helpful but not decisive: it fades on some individuals and several harmless spiders have similar markings.
How it behaves
Nocturnal and, as the name says, reclusive. It hides in cardboard, stored clothing, behind furniture and in wall voids, and runs for cover when exposed. Bites usually happen when a spider is trapped against skin — pulling on stored clothing, rolling over in bed, reaching into a box.
What the brown recluse is confused with
One observation settles each of these.
Wolf spiders are much larger, patterned, hairy, and have eight eyes including two large forward-facing ones that shine in torchlight.
Sac spiders are pale yellow-green with dark mouthparts and no violin mark.
Male southern house spiders are the commonest false recluse in the deep south — longer-legged, with visible palps like boxing gloves at the front.