Brown Recluse Spiders: What to Know

Medically Reviewed by Jabeen Begum, MD on March 03, 2023
4 min read

It’s rare for someone to stumble upon a brown recluse spider because these eight-legged creatures are true to their name: They prefer to be left alone. They tend to live in indoor and outdoor spaces where people don’t go most of the time. If you do find yourself in the same place as one, though, it won’t want to attack you -- it’ll want to get out of your way. But if it feels trapped, it may bite you.

Brown recluse spiders are one of two spiders found in the United States that can cause real trouble if they bite you. They produce harmful venom that may cause a painful sore at the site of the bite. It may cause even more severe symptoms in some people. If you have a run-in with a brown recluse, it’s wise to have a doctor check you out, just in case.

A brown recluse might not be brown, but tan. It has a violin-shaped area on the front half of its body, with the neck of the violin pointing toward the spider’s abdomen.

It may be bigger than other spiders that you’re used to seeing. Its body can range in size from a quarter-inch to three-quarters of an inch, and its long legs make it appear even larger.

Most spiders have eight eyes, but a brown recluse spider has six. Two are in the front, and there are two more on each side of its head.

Brown recluses are found mostly in the Midwest or the South. The spider favors indoor spaces, like attics, garages, or dark closets. Outdoors, it hides in out-of-the-way places -- under logs, beneath porches, or within piles of rocks.

Brown recluse spider bites often go unnoticed initially because they are usually painless bites. Occasionally, some minor burning that feels like a bee stingis noticed at the time of the bite. Symptoms usually develop 2-8 hours after a bite. Keep in mind that most bites cause little tissue destruction.

Initially the bite site is mildly red and upon close inspection may reveal fang marks. Within a few hours, the redness gives way to pallor with a red ring surrounding the area, or a "bull's-eye" appearance. The lesion will often appear to flow downhill over the course of many hours. The center area will then often blister, which over 12-48 hours can sink, changing color, often turning bluish then black as this area of tissue dies.

Within the first day or two after you’ve been bitten, you may notice:

  • Pain or redness at the site of the bite
  • A deep sore (ulcer) that forms where you were bitten
  • Fever
  • Chills
  • Nausea
  • Joint pain
  • Feeling weak
  • Seizures or coma (very rare)

Your doctor will want to be as certain as they can that you were, in fact, bitten by a spider. It’ll help if you can describe what the spider looked like. Some people try to catch the bug to show the doctor. That’s fine, as long as you can do it safely. You might just try to take a photo of it.

If you suspect your small child was bitten by a brown recluse, see your doctor right away. Their bodies can’t ward off the dangerous effects of the spider’s venom.

For adults, most brown recluse spider bites can be treated at home with good results. But about 10% of them cause ulcers or blisters that damage your skin so badly that you need a doctor’s care.

If your symptoms are mild, try these simple home remedies:

  • Clean it with soap and water.
  • Apply antibiotic cream.
  • If you were bitten on an arm or leg, keep it raised while you’re resting. This can reduce swelling.
  • Put ice on it.
  • Take over-the-counter pain medicine.
  • Watch for more severe symptoms.

See a doctor right away if you notice any of these symptoms:

  • The bite has formed an ulcer or blister with a dark (blue, purple, or black) center.
  • You’re in extreme pain.
  • You have an infection at the site of the bite.
  • You’re having trouble breathing.

Some spider bites can have tetanus spores, so you might need a tetanus shot after you’ve been bitten. If you have an infection, you may need antibiotics.