Written & Edited by: Nadia Drake, Clifton Castleman, Rick Vetter

Brown Recluse – The Hype

Brown Recluse Spider

It’s hard to think of a critter that inspires as much hyperbolic hysteria as the Brown Recluse spider (Loxosceles reclusa). They’re pretty much universally hated. If you believe the tales, these small arachnids are biting people all day, every day, producing massive, stinking flesh-craters that require months of intensive care and perhaps a prosthetic appendage. Sometimes, it seems these spiders have nothing better to do than hunker down in dark corners throughout North America, waiting for tender human skin to present itself.

Though there are strands of truth in the hype, on the whole, it’s bunk.

It's true that some of the spider’s bites lead to necrotic skin lesions, but in actuality, only around 10 percent of them do. The rest don't tend to get that bad. Believe it or not, the Brown Recluse (Loxosceles reclusa) only lives in a few states – basically, the warmer ones between the Rockies and the Appalachians. This is because physiologically, they need a certain type of climate to survive.

This isn't to say that there haven't been transients that hitched a ride to other states (or countries for that matter), but it does mean that they cannot (and do not) thrive in other climates. Oh... and they don’t really want to bite you. In fact, it's not even that easy for them. In fact, the spiders’ fangs are too short and small to bite through pajamas or socks, and really only sturdy enough to puncture thin skin. Most bites occur when people roll over on the spiders in the night, or try to wear a shoe the spider has moved into. "Biting is a response to being crushed, but they'd much rather try and get away.

The Brown Recluse reality is obscured by a number of factors, not the least of which involves gnarly internet photos. First, spiders in general are easy to fear, and misinformation about this species in particular abounds. There is a really strong emotional and psychological aspect to the Brown Recluse – and most spiders in general, if we're being honest. Second, bite wound statistics are clouded by misreporting. Third, many other conditions can be misdiagnosed as brown recluse bites (like MRSA and fungal infections). Lastly, many other spiders (and insects) are mistaken for brown recluses.

First, a TRUTH: Brown recluse bites can be bad. They are a potentially dangerous spider, they’re not harmless. But the reputation they have garnered in this country is just amazing.

Mistaken Identities

A lot of work has involved verifying the identity of spiders purported to be Brown Recluses. In 2005, a study was published, showing the results of a nationwide appeal for spider specimens suspected to be "Brown Recluse spiders." The study received 1,773 specimens from 49 states. Less than 20 percent (324 to be exact) were Brown Recluses. All but four of those came from states with endemic brown recluse populations. It became evident early in the study that all that was required was some brown body coloration and eight legs. Oops!

Along the way, the study started showing that that even "authorities" (such as poison control centers and physicians) weren't much better at identifying the Brown Recluse. Even trained entomologists can get it wrong on occasion!

Brown Recluse Spider Look Alikes

Identifying the Brown Recluse Spider

Brown Recluse Spider

Part of the problem of properly identifying Brown Recluse spiders, is that they are typically very small and brown — about the size of a quarter, like many other arachnids and insects. One of the best way to identify a Brown Recluse is to count its eyes: They’re among a few species of North American spiders that have six eyes instead of eight, arranged in three pairs of two.

But your typical spider-squisher isn’t going to get in a spider’s face with a magnifying glass and count its eyes. Some people may try to find the marking most commonly described as identifying a Brown Recluse: a violin shape on the spider's back, oriented with the violin’s neck pointing toward the spider’s rear. However, people are incredibly good at "seeing" violin markings on every portion of a spider’s body, which means this marking is NOT an especially helpful diagnostic.

Look at the color.
A Brown Recluse has a dirt or sandy brown body with a slightly darker marking at its center; they can also be dark brown and even slightly yellow. Its legs are a lighter brown and completely uniform in color, with no additional markings.

Examine the violin shape on the spider's body.

It's a slightly darker brown color than the rest of the body, or cephalothorax. The violin shape isn't clearly defined, so it may not look to you exactly like the musical instrument.

Count the eyes.

The Brown Recluse, unlike other spiders, has only six eyes. They are arranged in pairs: one pair is in the center, and there's a pair on either side. Because the eyes are so small, it can be difficult to see them without a magnifying glass. If you count eight eyes, you're not looking at a recluse. (Please be safe when counting - you don't want to conclude there are six just to have it suddenly bite you!)

Look for fine hairs.

The Brown Recluse has many fine, short hairs on its body and legs. Unlike some other spiders, it does not have spines on its body or legs. If you see a spider with spines or thick hair, it's definitely not a recluse.

Check the body width.

The Brown Recluse's body doesn't grow to be larger than ½ inch (1.3 cm). If you're looking at a spider that's larger than this, it's a different type of spider.

Know what regions Recluses inhabit.

The Brown Recluse lives primarily in the southeastern United States. Populations are established in 15 states: Alabama, Arkansas, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Ohio, Oklahoma, Tennessee, and Texas.If you don't live in this region, then it is em>highly unlikely that you will encounter a brown recluse, although it is possible you may have encountered a transient. Contrary to popular myth, Brown Recluse spiders do NOT live in California.

Brown Recluse Range Map

Brown Recluse Spider Bites

The initial bite of the Brown Recluse usually doesn't cause pain. In fact, most people who were bitten by a Brown Recluse spider never felt the bite itself. This means that you may not be aware of the bite for as long as 8 hours, at which time the bite area will become red, tender and swollen. Most Brown Recluse bites tend to present with pain at the bite site within several hours. Specifically, Brown Recluse spider bites are well recognized for their “red, white and blue” ringed bite.

In addition to the bite site itself, in most instances the bite alone is the worst symptom, but sensitive people and children may develop other symptoms. Monitor your body for these symptoms that may occur: chills, a general feeling of illness, fever, nausea (but not vomiting), unusual sweating, and general malaise (tiredness).

The unfortunate thing about Brown Recluse bites is that there are well over 40 different well-documented things that can masquerade as a supposed "Brown Recluse bite." These include bacterial infections, viral infections and fungal infections; poison oak and poison ivy; thermal burns, chemical burns; bad reactions to blood thinners; and even herpes – just to name a few! As study after study have shown, the number of misdiagnosed "bites" far outweighs the actual number of bites.

In reality, just 10 percent of Recluse bites require medical attention. The rest look like little pimples or mosquito bites or something else that doesn't merit a trip to the emergency room, and they heal by themselves. Even with the science to back up the numbers, the reality of bite statistics doesn't seem to matter. Even when faced with numbers and geographic distribution maps, people still cling tightly to their beliefs about the recluse and its arachnid malfeasance.

Brown Recluse Venom

The venom of Brown Recluse spiders contains a variety of enzymes such as sphingomyelinase D, hyaluronidase, alkaline phosphatase and 5-ribonucleotide phosphohydrolase. Together these components cause blood coagulation. More specifically, platelet aggregation is stimulated when sphingomyelinase D reacts with sphingomyelin which releases N-acylsphingosine and choline when calcium or amyloid protein is present. The lack of blood flow around the bite site causes tissue necrosis. Polymorphonuclear leukocyte infiltration also partakes in the ischemia with the releasing of inflammatory mediators and associating with the local reaction.

Brown Recluse Bite Stages

Brown recluse spiders only bite as a defense mechanism. The site of the bite will initially begin with two small puncture wounds and surrounded by erythema. Next the center of the reaction site will become pale while the outer edge remains red. Vasospasm of the reaction site will increase pain to severe levels. Throughout the next few days a blister forms and the center of the bite site will transform into a blue, hard, stellate ulcer. Eventually the wound will heal by secondary intention with the potential of skin sloughing. Total time of healing can last several weeks.

Treating a Brown Recluse Bite

Seek professional medical treatment! The danger with a bite from this spider is severe tissue damage, and in *rare* cases it can cause someone to fall into a coma. Seek medical treatment as soon as you realize you were bit by a brown recluse. Seek immediate medical attention if a child or an elderly person has been bitten; the bite of the brown recluse spider is most dangerous to such persons and can produce very severe symptoms. While waiting to get emergency medical treatment, you can take these immediate first aid steps:

  Wash the bite area with soap and water
  Apply an ice pack directly to the bite area for ten minutes, then remove it for ten minutes.
  Repeat until you reach medical facilities.


Learn More about the Brown Recluse Spider at the University of California.