Brown recluse spider
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Class: Arachnida Order: Araneae Family: Sicariidae Genus: Loxosceles Species: L. reclusa
Binomial name
Loxosceles reclusa Gertsch & Mulaik, 1940

The brown recluse spider, Loxosceles reclusa, is a well-known member of the family Sicariidae (formerly placed in a family "Loxoscelidae"). It is usually between 6–20 mm (¼ in and ¾ in) but may grow larger. It is brown and sometimes an almost deep yellow color and usually has markings on the dorsal side of its cephalothorax, with a black line coming from it that looks like a violin with the neck of the violin pointing to the rear of the spider, resulting in the nicknames fiddleback spider, brown fiddler or violin spider. Coloring varies from light tan to brown and the violin marking may not be visible. Brown recluse spider, Loxosceles reclusa; public domain from http://phil. ... Scientific classification redirects here. ... For other uses, see Animal (disambiguation). ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ... For other uses, see Arachnid (disambiguation). ... For other uses, see Spider (disambiguation). ... Sicariidae are members of a genus of spiders found in arid portions of South America and southern Africa. ... This page is a candidate for speedy deletion. ... Latin name redirects here. ... Willis J. Gertsch (1906 - 1998) was an entomologist specialising in arachnology. ... Image File history File links Size of this preview: 800 × 370 pixel Image in higher resolution (1357 × 628 pixel, file size: 29 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Brown recluse spider... For other uses, see Spider (disambiguation). ... Sicariidae are members of a genus of spiders found in arid portions of South America and southern Africa. ... A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ... An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ... In anatomy, the dorsum is the upper or back side of an animal, as opposed to the ventrum. ... The cephalothorax is an anatomical term used of arachnid and malacostracan arthropods for the first major body section. ... For the Anne Rice novel, see Violin (novel). ...

Description

Since the "violin pattern" is not diagnostic, and other spiders may have similar marking (i.e. cellar spiders and pirate spiders), for purposes of identification it is far more important to examine the eyes. Differing from most spiders, which have eight eyes, recluse spiders have six eyes arranged in pairs (dyads) with one median pair and two lateral pairs. Only a few other spiders have 3 pairs of eyes arranged this way (e.g., scytodids), and recluses can be distinguished from these as recluse abdomens have no coloration pattern nor do their legs, which also lack spines.^[1] Diversity 80 genera, 959 species Genera Holocnemus Modisimus Pholcus Physocyclus Smeringopus Spermophora  many others The Pholcidae are a spider family in the suborder Araneomorphae. ... Genera 12 genera, including: Mimetus Ero The pirate spiders, also known as cannibal spiders (family Mimetidae) are a family of spiders that typically feed on other spiders. ... Etymology: Late Latin dyad-, dyas, from Greek, from dyo The word dyad has a number of uses: A dyad (general) pair, consisting of two parts. ... This article is about the statistical concept. ... Human anatomical terms make up a distinct nomenclature to describe areas of the body, to provide orientation when describing parts of human anatomy,[1] and to distinguish different movements of the body. ... Genera Scytodes Spitting spiders (family Scytodidae) are spiders of the genus Scytodes and their relatives. ...

Habitat

Recluse spiders build irregular webs that frequently include a shelter consisting of disorderly threads. These spiders frequently build their webs in woodpiles and sheds, closets, garages, cellars and other places that are dry and generally undisturbed. They seem to favor cardboard when dwelling in human residences, possibly because it mimics the rotting tree bark which they naturally inhabit. They also go in shoes, inside dressers, in bed sheets of infrequently used beds, in stacks of clothes, behind baseboards, behind pictures and near furnaces. The common source of human-recluse contact is during the cleaning of these spaces, when their isolated spaces suddenly are disturbed and the spider feels threatened. Unlike most web weavers, they leave these webs at night to hunt. Males will move around more when hunting while females don't usually stray far from their web.

Distribution

The brown recluse spider is native to the United States from the southern Midwest south to the Gulf of Mexico.^[2] The native range lies roughly south of a line from southeastern Nebraska through southern Iowa, Illinois, and Indiana to southwestern Ohio. In the southern states, it is native from central Texas to western Georgia. They are generally not found west of the Rocky Mountains.^[3] A related species, the brown violin spider (Loxosceles rufescens), is found in Hawaii.^[4] Despite many rumors to the contrary, the Brown Recluse Spider has not established itself in California, nor Canada.^[5] The Midwest is a common name for a region of the United States of America. ... Gulf of Mexico in 3D perspective. ... For other uses, see Nebraska (disambiguation). ... This article is about the U.S. state. ... This article is about the U.S. State. ... For other uses, see Indiana (disambiguation). ... This article is about the U.S. State. ... For other uses, see Texas (disambiguation). ... For individual mountains named Rocky Mountain, see Rocky Mountain (disambiguation). ... This article is about the U.S. State. ...

Venomous bite

As indicated by its name, this spider is not aggressive and usually bites only when pressed against the skin, such as when tangled up within clothes, bath towels, or in bedding.^[6] In fact, many wounds that are necrotic and diagnosed as brown recluse bites can actually be Methicillin-resistant Staphylococcus aureus (MRSA).^[6] Actual brown recluse bites are rare. Brown recluse bites may produce a range of symptoms known as loxoscelism. There are two types of loxoscelism: cutaneous (skin) and systemic (viscerocutaneous). For the town, see Recluse, Wyoming. ... MRSA redirects here. ... A condition produced by the bite of the brown recluse spider of North America and characterized by a gangrenous slough at the site of bite, nausea, malaise, fever, hemolysis, and thrombocytopenia. ... This article is about skin in the biological sense. ...

Most bites are minor with no necrosis. However, a small number of bites produce severe dermonecrotic lesions, and, sometimes, severe systemic symptoms, including organ damage. Rarely, the bite may also produce a systemic condition with occasional fatalities. Most fatalities are in children under 7 or those with a weaker than normal immune system. (For a comparison of the toxicity of several kinds of spider bites, see the list of spiders having medically significant venom.) Necrosis (in Greek Νεκρός = Dead) is the name given to accidental death of cells and living tissue. ... Chelicerae of a black wishbone (Nemesiidae) spider, a mygalomorph Spiders occasionally bite humans. ...

A minority of brown recluse spider bites form a necrotizing ulcer that destroys soft tissue and may take months to heal, leaving deep scars. The damaged tissue will become gangrenous and eventually slough away. The initial bite frequently cannot be felt and there may be no pain, but over time the wound may grow to as large as 10 inches (25 cm) in extreme cases. Bites usually become painful and itchy within 2 to 8 hours, pain and other local effects worsen 12 to 36 hours after the bite with the necrosis developing over the next few days.^[7] Endoscopic images of a duodenal ulcer. ... This article does not cite any references or sources. ... Gangrene is a complication of necrosis (i. ...

Serious systemic effects may occur before this time, as the venom spreads throughout the body in minutes. Mild symptoms include nausea, vomiting, fever, rashes, and muscle and joint pain. Rarely more severe symptoms occur including hemolysis, thrombocytopenia, and disseminated intravascular coagulation.^[8] Debilitated patients, the elderly, and children may be more susceptible to systemic loxoscelism. Deaths have been reported for both the brown recluse and the related South American species L. laeta^[9] and L. intermedia.^{[citation needed]} Other recluse species such as the desert recluse (found in the desert southwestern United States) are reported to have caused necrotic bite wounds.^{[citation needed]} For other uses, see Nausea (disambiguation). ... Heaving redirects here. ... An analogue medical thermometer showing the temperature of 38. ... A rash is a change in skin which affects its color, appearance, or texture. ... {{otheruses4|1=medical hemoglobin]] into the surrounding fluid (plasma, in vivo). ... Thrombocytopenia (or -paenia, or thrombopenia in short) is the presence of relatively few platelets in blood. ... Disseminated intravascular coagulation (DIC) is a pathological process in the body where the blood starts to coagulate throughout the whole body. ...

Numerous other spiders have been associated with necrotic bites in the medical literature. A partial list includes the hobo spider and the yellow sac spiders. However, the bites from these spiders are not known to produce the severe symptoms that often follow from a recluse spider bite, and the level of danger posed by each has been called into question.^[10][11] So far, no known necrotoxins have been isolated from the venom of any of these spiders, and some arachnologists have disputed the accuracy of many spider identifications carried out by bite victims, family members, medical responders, and other non-experts in arachnology. There have been several studies questioning danger posed by some of these spiders. In these studies, scientists examined case studies of bites in which the spider in question was positively identified by an expert, and found that the incidence of necrotic injury diminished significantly when "questionable" identifications were excluded from the sample set.^[12][13] Binomial name {Walckenaer, 1802} The hobo spider (Tegenaria agrestis) is a member of the genus of spiders known colloquially as funnel web spiders. ... Binomial name Hentz, 1847 The Yellow sac spider (Cheiracanthium inclusum and Chiracanthium mildei), alternately known as the black-footed spider, is not a true sac spider (of the family Clubionidae), but a long-legged sac spider, that is, a member of the family Miturgidae that was formerly classified in that...

Bite treatment

First aid involves the application of an ice pack to control inflammation, the application of aloe vera to soothe and help control the pain, and prompt medical care. If it can be easily captured, the spider should be brought with the patient in a clear, tightly closed container so it may be identified. However, by the time the bite is noticed any spider found nearby is not likely to be the culprit. An abscess on the skin, showing the redness and swelling characteristic of inflammation. ...

There is no established treatment for necrosis. Routine treatment should include elevation and immobilization of the affected limb, application of ice, local wound care, and tetanus prophylaxis. Many other therapies have been used with varying degrees of success including hyperbaric oxygen, dapsone, antihistamines (e.g., cyproheptadine), antibiotics, dextran, glucocorticoids, vasodilators, heparin, nitroglycerin, electric shock, curettage, surgical excision, and antivenom. None of these treatments have been subjected to controlled, randomized trials to conclusively show benefit. In almost all cases, bites are self-limited and typically heal without any medical intervention.^[3] Necrosis (in Greek Νεκρός = Dead) is the name given to accidental death of cells and living tissue. ... Hyperbaric oxygen therapy (HBOT) is the medical use of oxygen at a higher than atmospheric pressure. ... Dapsone is an antibiotic medication most commonly used for the treatment of Mycobacterium leprae infections (leprosy). ... Cyproheptadine (usually as cyproheptadine hydrochloride, trade name Periactin) is an antihistaminic and antiserotonergic agent. ... An antibiotic is a drug that kills or slows the growth of bacteria. ... Dextran is a complex branched polysaccharide made of many glucose molecules joined into chains of varying lengths. ... The name glucocorticoid derives from early observations that these hormones were involved in glucose metabolism. ... Heparin, a highly sulfated glycosaminoglycan is widely used as an injectable anticoagulant and has the highest negative charge density of any known biological molecule. ... Nitroglycerin (NG), also known as nitroglycerine, trinitroglycerin, and glyceryl trinitrate, is a chemical compound. ... Sign warning of possible electric shock hazard An electric shock can occur upon contact of a humans body with any source of voltage high enough to cause sufficient current flow through the muscles or hair. ... In surgery, the use of a curette to remove tissue by scraping or scooping. ... “Surgeon” redirects here. ... Antivenom (or antivenin, or antivenene) is a biological product used in the treatment of venomous bites or stings. ...

It is important to seek medical treatment if a brown recluse bite is suspected, as in the rare cases of necrosis the effects can quickly spread, particularly when the venom reaches a blood vessel. Cases of brown recluse venom traveling along a limb through a vein or artery are rare, but the resulting mortification of the tissue can affect an area as large as several inches, to the extreme of requiring excising of the wound. While it is possible, and even likely, that many cases of "brown recluse bites" are indeed misidentifications of other infections or envenomations, the brown recluse has justly earned its reputation.

Specific treatments

Dapsone is commonly used in the USA and Brazil for the treatment of necrosis. There have been conflicting reports about its efficacy and some have suggested it should no longer be used routinely, if at all.^[14] Dapsone is an antibiotic medication most commonly used for the treatment of Mycobacterium leprae infections (leprosy). ... Motto: (traditional) In God We Trust (official, 1956–present) Anthem: The Star-Spangled Banner Capital Washington, D.C. Largest city New York City Official language(s) None at the federal level; English de facto Government Federal Republic  - President George W. Bush (R)  - Vice President Dick Cheney (R) Independence - Declared - Recognized...

Wound infection is rare. Antibiotics are not recommended unless there is a credible diagnosis of infection.^[15]

Studies have shown surgical intervention is ineffective and may worsen outcome. Excision may delay wound healing, cause abscesses, and lead to objectional scarring.^[16] An abscess is a collection of pus collected in a cavity formed by the tissue on the basis of an infectious process (usually caused by bacteria or parasites) or other foreign materials (e. ...

Anecdotal evidence suggests benefit can be gained with the application of nitroglycerin patches.^[17] The brown recluse venom is a vasoconstrictor, and nitroglycerin causes vasodilation, allowing the venom to be diluted into the bloodstream, and fresh blood to flow to the wound. Theoretically this prevents necrosis, as vasoconstriction may contribute to necrosis. However, one scientific animal study found no benefit in preventing necrosis, with results showing it increased inflammation and it caused symptoms of systemic envenoming. The authors concluded the results of the study did not support the use of topical nitroglycerin in brown recluse envenoming.^[18] Anecdotal evidence is an informal account of evidence in the form of an anecdote, or hearsay. ... Glyceryl trinitrate (GTN) is the pharmaceutical name for nitroglycerin. ... The blood vessels are part of the circulatory system and function to transport blood throughout the body. ...

Antivenom, available in South America, appears to be the most promising therapy. However, antivenoms are most effective if given early and because of the painless bite patients do not often present until 24 or more hours after the event, possibly limiting the effect of this intervention.^[19]

Misdiagnoses

It is estimated that 80% of reported brown recluse bites may be misdiagnosed. The misdiagnosis of a wound as a brown recluse bite could delay proper treatment of serious diseases.^[3] There is now a ELISA-based test for brown recluse venom that can determine if a wound is a brown recluse bite, although it is not commercially available and not in routine use.^[20][3] Elisa (born Elisa Toffoli on 19 December 1977) is an Italian singer and solo artist, writing and performing within several genres, notably rock, blues, soul and ambient. ...

There are numerous documented infectious and noninfectious conditions (including pyoderma gangrenosum, bacterial infections by Staphylococcus and Streptococcus, herpes, diabetic ulcer, fungal infections, chemical burns, toxicodendron dermatitis, squamous cell carcinoma, localized vasculitis, syphilis, toxic epidermal necrolysis, sporotrichosis, and Lyme disease) that produce wounds that have been initially misdiagnosed as recluse bites by medical professionals; many of these conditions are far more common and more likely to be the source of mysterious necrotic wounds, even in areas where recluses actually occur.^[3] Staphylococcus (in Greek staphyle means bunch of grapes and coccos means granule) is a genus of Gram-positive bacteria. ... Species S. agalactiae S. bovis S. mutans S. pneumoniae S. pyogenes S. salivarius S. sanguinis S. suis Streptococcus viridans Streptococcus uberis etc. ... ... Species See text. ... Biopsy of a highly differentiated squamous cell carcinoma of the mouth. ... Vasculitis (plural: vasculitides), a group of diseases featuring inflammation of the wall of blood vessels including veins (phlebitis), arteries (arteritis) and capillaries due to leukocyte migration and resultant damage. ... Syphilis is a curable sexually transmitted disease caused by the Treponema pallidum spirochete. ... Toxic epidermal necrolysis is a life-threatening and usually drug-induced dermatological condition that occurs more often in women than in men. ... Sporotrichosis is a disease caused by the infection of the fungus Sporothrix schenckii (S. schenckii). ... Lyme disease, or borreliosis, is an emerging infectious disease caused by at least three species of bacteria from the genus Borrelia. ...

Reported cases of bites occur primarily in Arkansas, Texas, Kansas, Missouri, Colorado, and Oklahoma. There have been many reports of brown recluse bites in California (and elsewhere outside the range of the brown recluse); however the brown recluse is not found in California^[21] (though a few related species may be found there, none of which has been shown to bite humans). To date, the reports of bites from areas outside of the spider's native range have been either unverified, or - if verified - specimens moved by travelers or commerce. Gertsch and Ennik (1983) report that occasional spiders have been intercepted in various locations where they have no known established populations; Arizona, California, Colorado, Florida, Maine, Minnesota, New Jersey, Mexico, New York, North Carolina, Wyoming and Tamaulipas (Mexico),^[22] which indicates that these spiders may indeed be transported fairly easily, though the lack of established populations well outside the natural range also indicates that such movement does not lead to colonization of new areas. Many arachnologists believe that many bites attributed to the brown recluse in the West Coast are not spider bites at all, or possibly instead the bites of other spider species; for example, the bite of the hobo spider has been reported to produce similar symptoms, and is found in the northwestern United States and southern British Columbia in Canada. However, the toxicity of the hobo spider has been called into question as bites have not been proven to cause necrosis, and the spider is not considered a problem in its native Europe.^[23] In addition, published work has shown that tick-induced Lyme disease rashes are often misidentified as brown recluse spider bites.^[24] This article is about the U.S. State. ... For other uses, see Texas (disambiguation). ... This article is about the U.S. state. ... This article is about the U.S. state. ... Official language(s) English Demonym Coloradan Capital Denver Largest city Denver Largest metro area Denver-Aurora Metro Area Area  Ranked 8th in the US  - Total 104,185 sq mi (269,837 km²)  - Width 280 miles (451 km)  - Length 380 miles (612 km)  - % water 0. ... For other uses, see Oklahoma (disambiguation). ... This article is about the U.S. state. ... Official language(s) English Spoken language(s) English 74. ... This article is about the U.S. state. ... Official language(s) English Demonym Coloradan Capital Denver Largest city Denver Largest metro area Denver-Aurora Metro Area Area  Ranked 8th in the US  - Total 104,185 sq mi (269,837 km²)  - Width 280 miles (451 km)  - Length 380 miles (612 km)  - % water 0. ... This article is about the U.S. State of Florida. ... Official language(s) None (English and French de facto) Capital Augusta Largest city Portland Area  Ranked 39th  - Total 33,414 sq mi (86,542 km²)  - Width 210 miles (338 km)  - Length 320 miles (515 km)  - % water 13. ... Capital Saint Paul Largest city Minneapolis Largest metro area Minneapolis-St. ... This article is about the U.S. state. ... This article is about the state. ... Official language(s) English Demonym North Carolinian Capital Raleigh Largest city Charlotte Largest metro area Charlotte metro area Area  Ranked 28th in the US  - Total 53,865 sq mi (139,509 km²)  - Width 150 miles (340 km)  - Length 560[1] miles (900 km)  - % water 9. ... Official language(s) English Capital Cheyenne Largest city Cheyenne Area  Ranked 10th  - Total 97,818 sq mi (253,348 km²)  - Width 280 miles (450 km)  - Length 360 miles (580 km)  - % water 0. ... Tamaulipas is a state in the northeast of Mexico. ... Regional definitions vary from source to source. ... Binomial name {Walckenaer, 1802} The hobo spider (Tegenaria agrestis) is a member of the genus of spiders known colloquially as funnel web spiders. ... Motto: Splendor sine occasu (Latin: Splendour without diminishment) Capital Victoria Largest city Vancouver Official languages English (de facto) Government Lieutenant-Governor Steven Point Premier Gordon Campbell (BC Liberal) Federal representation in Canadian Parliament House seats 36 Senate seats 6 Confederation July 20, 1871 (6th province) Area  Ranked 5th Total 944... For other uses, see Europe (disambiguation). ... Families Ixodidae - Hard ticks Argasidae - Soft ticks Nuttalliellidae - ????? ticks Wikispecies has information related to: Ixodoidea Tick is the common name for the small arachnids that, along with other mites, constitute the order Acarina. ... Lyme disease, or borreliosis, is an emerging infectious disease caused by at least three species of bacteria from the genus Borrelia. ...

Footnotes

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 245th day of the year (246th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 344th day of the year (345th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 122nd day of the year (123rd in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 245th day of the year (246th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 245th day of the year (246th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links

Wikimedia Commons has media related to:

Loxosceles reclusa

• Myth of the Brown Recluse (Fact, Fear, and Loathing in California)
• Description of brown recluse
• Illinois and Iowa Brown Recluse Project requesting specimens from public
• Brown Recluse Spider Pictures and comments about the damage this spider can do.
• The Brown Recluse Information about the brown recluse spider based on peer reviewed journals.

The Brown Recluse spider has also been known to make appearences in york county, maine