Brown Recluse Control: Accurate ID, Real Risks and How to Reduce Them

You found a brown spider in the closet, or someone in the house has a sore that a friend says looks like a recluse bite. Brown recluses are real and their bites can be serious, but they are also one of the most over-reported pests in the country. This guide shows you how to confirm what you have, where recluses actually live, what to do about a bite, and how to cut down an infestation.

How to identify a brown recluse

Many harmless brown spiders get mistaken for recluses, so check several features, not just one. A spider needs all five of these traits to be a recluse:

The violin mark is why people call it the fiddleback, but it is the weakest clue. It varies in strength, is faint on young spiders, and is faint or missing on some other recluse species. The eye pattern is the most reliable feature. You will need a good hand lens or a sharp, zoomed-in photo to see it.

If you are not sure, have the spider confirmed by an extension entomologist or a pest control professional. To preserve one, freeze it, soak it in rubbing alcohol for a few days, then rinse it before mailing. Do not mail it in alcohol. If you are not in recluse territory, our spider control guide covers the common house spiders it is more likely to be.

Where brown recluses live

The brown recluse is native to the south-central Midwest: roughly from southeastern Nebraska to southwestern Ohio, and south through Texas to north Georgia. Within that range, populations can be dense where conditions suit them, and a single home can hold anywhere from one or two spiders to several hundred.

Outside that range, they are rare. A few occasionally ride along in boxes or furniture from out of state, but they seldom establish a population. California has no established brown recluse populations; fewer than 20 verified specimens have been collected there over several decades. Other recluse species do live in parts of the Southwest, such as the desert recluse.

Signs of brown recluses

Recluses hunt at night and do not catch prey in webs. The cobwebs in your corners belong to other spiders, some of which eat recluses. Look for:

• Spiders on sticky traps along baseboards and behind furniture.
• Small, irregular silk retreats in dark, undisturbed spots.
• Shed skins that look stretched out. These help confirm an infestation.
• Off-white silk egg sacs about 1/3 inch across.
• Spiders in shoes, clothing on the floor, bedding or stored boxes.

Indoors they hide in closets, attics, unheated basements, crawl spaces, wall voids, behind baseboards and furniture, and in stored items. Outdoors they live under rocks, logs, woodpiles, plywood, tires and debris. They can survive many months without food or water, so an empty house does not starve them out.

Bites: what is real and what is misdiagnosed

Recluses are not aggressive. Bites usually happen when a spider gets pressed against skin, such as when you roll over in bed or put on a shoe or shirt it is hiding in. Their fangs are tiny and cannot bite through clothing.

The bite is often painless at first. Redness, swelling and tenderness may show up 3 to 8 hours later. Most bites cause only inflammation and heal on their own within a few weeks. About 1 in 10 brown recluse bites causes moderate or worse tissue damage. In those cases a sunken, bluish patch with a pale center and red edges can spread over days or weeks and leave a scar. Less often, bites cause fever, chills, dizziness, rash or vomiting. Children, older adults and people in poor health are more likely to react badly.

A recluse bite is hard to confirm from the wound alone, even for a doctor. Conditions that often get blamed on recluses include:

• MRSA and other bacterial skin infections. In one national study of patients reporting a spider bite, MRSA turned out to be the cause in 29% of cases (the study covered 11 university medical centers).
• Strep infections, including necrotizing fasciitis, which can be life threatening if diagnosis is delayed.
• Bites from fleas, bed bugs, mites, ticks or mosquitoes.
• Diabetic and pressure ulcers, shingles, burns, poison ivy or poison oak, and Lyme disease.

Several sores at once, sores on widely separated parts of the body, sores that keep coming back, or several people with sores at the same time all point away from spiders. So does living outside the recluse range. If you suspect bites from a pest you never saw, our guide to signs of bed bugs and our flea guide can help you check other causes.

When to see a doctor: after a suspected recluse bite, wash it with soap and water, apply ice or a cold, damp cloth, keep it raised, and get medical care, especially if the wound blisters, darkens or spreads, or if you develop fever, chills, rash or vomiting. Bring the spider if you caught it, even crushed. Do not try to remove the venom yourself. Antibiotics do not work on venom, so a doctor will treat any infection separately.

How to get rid of brown recluses

1. Confirm the spider. Check the eyes and legs, or have a specimen identified. Do not start treatment until you know recluses are present.
2. Inspect with a bright flashlight. Check closets, shoes, stored boxes, corners, the joint where walls meet floors, behind furniture and baseboards, attics, basements, crawl spaces and garages. Wear gloves and long sleeves when you handle boxes.
3. Set out sticky traps. Use flat glue cards without raised edges and place plenty of them along baseboards, in corners and behind furniture, out of reach of children and pets. They catch a lot of wandering males, show you where activity is heaviest and tell you whether control is working. Put traps out before any insecticide treatment, because some products make spiders move around.
4. Cut the clutter. Fewer boxes, piles and stored items mean fewer hiding places and better results from any treatment. Store seasonal clothing and rarely used items in sealed plastic bins or bags.
5. Protect the bed. Move beds away from walls, remove bed skirts and clear out the space under the bed. Keep clothes and shoes off the floor, and shake them out before you put them on.
6. Fix the outside. Move firewood, lumber and debris away from the foundation. Seal gaps under doors, around vents and utility lines, at the bottom of siding and where eaves meet walls, especially around attached garages.
7. Kill the ones you see. Crushing a spider with a shoe or rolled newspaper is quick and uses no chemicals.

Insecticides are hard to use well against recluses because females stay hidden in cracks and voids. Professionals often apply dusts into wall voids, under insulation and behind outlet plates, and use sprays in cracks and other hiding spots. Total-release foggers rarely work. If you treat anything yourself, read and follow the label and see our guide to using pesticides safely.

When to call a professional

A single recluse in a box from a relative’s house is a sticky-trap and cleanup job. For an infestation, University of Kentucky entomologists advise leaving treatment to professionals, because recluses are secretive and hard to eliminate.

Call a pest control company if:

• Sticky traps keep catching recluses after a few weeks of cleanup and trapping.
• You are finding them in bedrooms, beds, clothing or shoes.
• Someone in the home is very young, elderly or in poor health.
• The spiders are in attics, crawl spaces, wall voids or other places you cannot reach.

A recluse job can take more than one visit. A thorough company will confirm the species, inspect inside and out, set monitoring traps, treat cracks and voids, recommend sealing and clutter changes, and come back to check traps and retreat. Ask:

• How did you confirm these are recluses?
• Where will you apply products, which active ingredients will you use, and how long should children and pets stay away?
• How many visits are included, and how will we measure progress?
• What sealing or repair work do you recommend, and do you do it?

Read our guide to choosing a pest control company before you sign a contract, and see pest control costs for what affects the price of a multi-visit plan.

Brown recluse questions

I found one recluse. Do I have an infestation? Not necessarily. Set out sticky traps for a few weeks. If you are outside the native range and catch nothing more, it was probably a stray. Inside the range, keep trapping, because a home infestation can be anything from a few spiders to several hundred.

Are recluses aggressive? No. They bite in self-defense, usually when pressed against skin inside a shoe, a piece of clothing or bedding.

Can I fog the house? Foggers rarely work against recluses. They do not reach the cracks and voids where the spiders hide, and treatments can make spiders wander more.