View source for Spider bite

{{Short description|Bite caused by a spider}}
{{For|the urban legend|The Spider Bite}}
{{For|the rock band|Spiderbait}}
{{Infobox medical condition (new)
| name            = Spider bite
| synonyms        =
| image           = Black Wishbone.jpg
| caption         = [[Chelicerae]] of a [[Aname atra|black wishbone]] ([[Nemesiidae|nemesiid]]) spider, a [[Mygalomorphae|mygalomorph]]
| pronounce       =
| field           = [[Emergency medicine]]
| symptoms        =
| complications   = [[Envenomation]]
| onset           =
| duration        =
| types           =
| causes          = [[Spiders]]
| risks           =
| diagnosis       =
| differential    =
| prevention      =
| treatment       =
| medication      =
| prognosis       =
| frequency       =
| deaths          =
}}
<!-- Definition and symptoms -->

A '''spider bite''', also known as '''arachnidism''', is an injury resulting from the bite of a [[spider]]. The effects of most bites are not serious.<ref name=Lancet2011>{{cite journal|last1=Isbister|first1=GK|last2=Fan|first2=HW|title=Spider bite.|journal=Lancet|date=10 December 2011|volume=378|issue=9808|pages=2039–47|pmid=21762981|doi=10.1016/s0140-6736(10)62230-1|s2cid=27408940}}</ref> Most bites result in mild symptoms around the area of the bite.<ref name=Lancet2011/> Rarely they may produce a necrotic skin wound or severe pain.<ref name="Andrews">{{cite book |author1=James, William D. |author2=Berger, Timothy G. |title=Andrews' Diseases of the Skin: clinical Dermatology |url=https://archive.org/details/andrewsdiseasess00mdwi_659 |url-access=limited |publisher=Saunders Elsevier |year=2006 |pages=[https://archive.org/details/andrewsdiseasess00mdwi_659/page/n465 455] |isbn=0-7216-2921-0 |display-authors=etal}}</ref>{{rp|455}}

<!-- Cause -->
Most spiders do not cause bites that are of importance.<ref name=Lancet2011/> For a bite to be significant, substantial [[envenomation]] is required. Bites from the [[Latrodectus|widow spider]]s involve a neurotoxic venom which produces a condition known as [[latrodectism]].<ref>{{cite journal |last=Braitberg |first=George |year=2009 |title=spider bites: Assessment and management |journal=Australian Family Physician |volume=38 |issue=11 |pages=862–67 |pmid=19893831 |url=http://www.racgp.org.au/afp/200911/200911braithberg.pdf |access-date=2014-04-06 |archive-date=2013-11-01 |archive-url=https://web.archive.org/web/20131101170857/http://www.racgp.org.au/afp/200911/200911braithberg.pdf |url-status=dead }}</ref> Symptoms may include pain which may be at the bite or involve the chest and abdomen, sweating, muscle cramps and vomiting among others.<ref name=Lancet2011/> Bites from the [[recluse spider]]s cause the condition [[loxoscelism]], in which local [[necrosis]] of the surrounding skin and widespread [[hemolysis|breakdown of red blood cells]] may occur.<ref name=Swanson2005>{{cite journal|last1=Swanson|first1=DL|last2=Vetter|first2=RS|title=Bites of brown recluse spiders and suspected necrotic arachnidism.|journal=The New England Journal of Medicine|date=17 February 2005|volume=352|issue=7|pages=700–07|pmid=15716564|doi=10.1056/nejmra041184}}</ref> Headaches, vomiting and a mild fever may also occur.<ref name=Swanson2005/> Other spiders that can cause significant bites include the [[Australian funnel-web spider]]<ref>{{cite journal|last1=Isbister|first1=GK|last2=Gray|first2=MR|last3=Balit|first3=CR|last4=Raven|first4=RJ|last5=Stokes|first5=BJ|last6=Porges|first6=K|last7=Tankel|first7=AS|last8=Turner|first8=E|last9=White|first9=J|last10=Fisher|first10=MM|title=Funnel-web spider bite: a systematic review of recorded clinical cases.|journal=The Medical Journal of Australia|date=18 April 2005|volume=182|issue=8|pages=407–11|pmid=15850438|doi=10.5694/j.1326-5377.2005.tb06760.x|hdl=2440/17349|s2cid=18066524|hdl-access=free}}</ref> and [[Phoneutria fera|South American wandering spider]].<ref name="Lancet2011" />

<!-- Prevention and treatment -->
Efforts to prevent bites include clearing clutter and the use of [[pesticide]]s.<ref name=Lancet2011/> Most spider bites are managed with supportive care such as [[nonsteroidal anti-inflammatory drug]]s (including [[ibuprofen]]) for pain and [[antihistamine]]s for itchiness.<ref name=Kang2014/> [[Opioids]] may be used if the pain is severe.<ref name=Kang2014/> While an [[antivenom]] exists for black widow spider venom, it is associated with [[anaphylaxis]] and therefore not commonly used in the United States.<ref name=Kang2014/> Antivenom against funnel web spider venom improves outcomes.<ref name=Lancet2011/> Surgery may be required to repair the area of injured skin from some recluse bites.<ref name=Kang2014>{{cite journal|last1=Kang|first1=JK|last2=Bhate|first2=C|last3=Schwartz|first3=RA|title=Spiders in dermatology.|journal=Seminars in Cutaneous Medicine and Surgery|date=September 2014|volume=33|issue=3|pages=123–27|pmid=25577851|url=http://admin.imng.com/fileadmin/content_pdf/san/scms_pdf/Vol_33_Iss_3_SPIDERS_IN_DERM.pdf|doi=10.12788/j.sder.0107|access-date=2015-02-15|archive-date=2015-02-14|archive-url=https://web.archive.org/web/20150214201651/http://admin.imng.com/fileadmin/content_pdf/san/scms_pdf/Vol_33_Iss_3_SPIDERS_IN_DERM.pdf|url-status=dead}}</ref>

<!-- Epidemiology and history-->
Spider bites may be overdiagnosed or misdiagnosed.<ref name=Lancet2011/> In many reports of spider bites it is unclear if a spider bite actually occurred.<ref name=StubNent16>{{Cite journal |last1=Stuber |first1=Marielle |last2=Nentwig |first2=Wolfgang |date=2016 |title=How informative are case studies of spider bites in the medical literature? |journal=Toxicon |volume=114 |pages=40–44 |doi=10.1016/j.toxicon.2016.02.023 |pmid=26923161  }}</ref> Historically a number of conditions were attributed to spider bites. In the Middle Ages a condition claimed to arise from spider bites was [[tarantism]], where people danced wildly.<ref name=Don1997>{{cite journal|last1=Donaldson|first1=LJ|last2=Cavanagh|first2=J|last3=Rankin|first3=J|title=The dancing plague: a public health conundrum.|journal=Public Health|date=July 1997|volume=111|issue=4|pages=201–04|pmid=9242030|doi=10.1016/s0033-3506(97)00034-6}}</ref> While necrosis has been attributed to the bites of a number of spiders, good evidence only supports this for recluse spiders.<ref name=Lancet2011/>

==Signs and symptoms==
[[File:BrownRecuse1.jpg|thumb|A Brazilian man 31 hours after having been bitten on his face by a [[recluse spider]]]]
[[File:BrownRecluse2 - scarring after spider bite.jpg|thumb|4 months after a brown recluse spider bite with scar remaining]]
Almost all spiders are venomous, but not all spider bites result in the injection of venom. Pain from non-venomous bites, so-called "dry bites", typically lasts for 5 to 60&nbsp;minutes while pain from envenomating spider bites may last for longer than 24&nbsp;hours.<ref name="GFD2010">{{cite web|url=http://www.globalfamilydoctor.com/search/GFDSearch.asp?itemNum=12031&ContType=HDA|title=Global Family Doctor|url-status=dead|archive-url=https://web.archive.org/web/20120313195505/http://www.globalfamilydoctor.com/search/GFDSearch.asp?itemNum=12031&ContType=HDA|archive-date=2012-03-13}}</ref> Bleeding also may occur with a bite. Signs of a bacterial infection due to a spider bite occur infrequently (0.9%).<ref name="GFD2010" />

A study of 750 definite spider bites in Australia indicated that 6% of spider bites cause significant effects, the vast majority of these being [[redback spider]] bites causing significant pain lasting more than 24 hours.<ref name=IsbiGray02>{{cite journal |vauthors=Isbister GK, Gray MR |title=A prospective study of 750 definite spider bites, with expert spider identification |journal=QJM |volume=95 |issue=11 |pages=723–31 |date=November 2002 |pmid=12391384 |doi= 10.1093/qjmed/95.11.723|doi-access=free }}</ref> Activation of the sympathetic nervous system can lead to sweating, high blood pressure and gooseflesh.<ref>{{cite journal|last1=Offerman|first1=SR|last2=Daubert|first2=GP|last3=Clark|first3=RF|title=The treatment of black widow spider envenomation with antivenin latrodectus mactans: a case series|journal=The Permanente Journal|date=Summer 2011|volume=15|issue=3|pages=76–81|pmid=22058673|pmc=3200105|doi=10.7812/tpp/10-136}}</ref>

Most [[recluse spider]] bites are minor with little or no necrosis. However, a small number of bites produce necrotic skin lesions. First pain and tenderness at the site begin. The redness changes over two to three days to a bluish sinking patch of dead skin—the hallmark of necrosis. The wound heals slowly over months but usually completely.<ref>{{cite news|last1=Sandlin|first1=Nina|title=Convenient culprit: Myths surround the brown recluse spider|url=http://www.amednews.com/article/20020805/health/308059999/4/|access-date=2 March 2015|publisher=American Medical Association|date=5 August 2002}}</ref> Rarely, bites may cause widespread symptoms, with occasional fatalities.<ref name="Vetter2013">{{cite journal|last1=Vetter|first1=RS|title=Spider envenomation in North America.|journal=Critical Care Nursing Clinics of North America|date=June 2013|volume=25|issue=2|pages=205–23|pmid=23692939|doi=10.1016/j.ccell.2013.02.006}}</ref>

There are a few [[spider]]s that can bite human skin and cause a [[cutaneous condition|skin reaction]], but spiders are blamed for many more reactions. In particular the misdiagnosis of infections and other skin ailments are commonly attributed to [[Loxosceles|brown recluses]].<ref name=":0">{{Cite journal|last1=Stoecker|first1=William V.|last2=Vetter|first2=Richard S.|last3=Dyer|first3=Jonathan A.|date=2017-05-01|title=NOT RECLUSE – A Mnemonic Device to Avoid False Diagnoses of Brown Recluse Spider Bites|journal=JAMA Dermatology|language=en|volume=153|issue=5|pages=377–78|doi=10.1001/jamadermatol.2016.5665|pmid=28199453|issn=2168-6068}}</ref>

{| class="wikitable"
|+ Spiders associated with skin reactions
|-
! Scientific name !! Common name !! Venom !! Reaction
|-
|''[[White-tailed spider|Lampona]]'' spp<ref>{{Cite journal|last1=White|first1=Julian|last2=Weinstein|first2=Scott A.|title=A phoenix of clinical toxinology: White-tailed spider (Lampona spp.) bites. A case report and review of medical significance|journal=Toxicon|volume=87|pages=76–80|doi=10.1016/j.toxicon.2014.05.021|pmid=24923740|year=2014}}</ref><ref name="WhiteTail">{{cite journal
 | first1=G. K. | last1=Isbister | first2=M. R. | last2=Gray | title=White-tail spider bite: a prospective study of 130 definite bites by Lampona species
 | journal=Medical Journal of Australia
 | volume=179
 | issue=4
 | pages=199–202
 | url=http://www.mja.com.au/public/issues/179_04_180803/isb10785_fm.html
| doi=10.5694/j.1326-5377.2003.tb05499.x
 | date=2003-08-18 | pmid=12914510
 | s2cid=46155627 | url-access=subscription}}</ref>
|White-tailed
|
|Welt
|-
| ''[[Loxosceles]]'' spp<ref name=":0" /> || Brown recluse || Sphingomyelinase
|Necrosis
|-
| ''[[Cheiracanthium]]'' spp || Sac || Lipase
|Redness
|-
| ''[[Tegenaria agrestis]]''<ref>{{Cite journal|last1=McKeown|first1=Nathanael|last2=Vetter|first2=Richard S.|last3=Hendrickson|first3=Robert G.|title=Verified spider bites in Oregon (USA) with the intent to assess hobo spider venom toxicity|journal=Toxicon|volume=84|pages=51–55|doi=10.1016/j.toxicon.2014.03.009|pmid=24726469|year=2014}}</ref> || Hobo || 
|Redness
|-
| [[Lycosidae]] spp<ref>{{Cite journal|last=Lucas|first=Sylvia M.|date=December 2015|title=The history of venomous spider identification, venom extraction methods and antivenom production: a long journey at the Butantan Institute, São Paulo, Brazil|journal=Journal of Venomous Animals and Toxins Including Tropical Diseases|language=En|volume=21|issue=1|pages=21|doi=10.1186/s40409-015-0020-0|pmid=26085831|issn=1678-9199|pmc=4470033 |doi-access=free }}</ref><ref>{{cite journal |last1=Isbister |first1=Geoffrey K. |last2=Framenau |first2=Volker W. |title=Australian Wolf Spider Bites (Lycosidae): Clinical Effects and Influence of Species on Bite Circumstances |journal=Journal of Toxicology: Clinical Toxicology |date=5 November 2004 |volume=42 |issue=2 |pages=153–61 |doi=10.1081/CLT-120030941|pmid=15214620 |s2cid=24310728 }}</ref> || Wolf ||
|Redness, itching
|}

==Cause==
{{Main article|List of medically significant spider bites}}
Spiders do not feed on humans and typically bites occur as a defense mechanism.<ref name="CDC2012W">{{cite web|title = Workplace Safety & Health Topics Venomous Spiders|url = https://www.cdc.gov/niosh/topics/spiders/|website = cdc.gov|access-date = 15 February 2015|date = February 24, 2012}}</ref> This can occur from unintentional contact or trapping of the spider.<ref name=CDC2012W/> Most spiders have fangs too small to penetrate human skin.<ref name=Diaz2004/> Most bites by species large enough for their bites to be noticeable will have no serious medical consequences.<ref>{{cite web | title =Spider Bite First Aid  | publisher = firstaidkits.org | url =http://www.firstaidkits.org/spider-bites.asp | access-date = 2007-08-23}}</ref>

Medically significant spider venoms include various combinations and concentrations of [[Necrosis|necrotic]] agents, [[neurotoxins]], and pharmacologically active compounds such as serotonin. Worldwide only two spider venoms have impact on humans—those of the widow and recluse spiders. Unlike [[Snakebite|snake]] and [[Scorpion sting|scorpion envenomation]],<ref>{{cite journal|last1=Chippaux|first1=JP|last2=Goyffon|first2=M|title=Epidemiology of scorpionism: a global appraisal.|journal=Acta Tropica|date=August 2008|volume=107|issue=2|pages=71–79|doi=10.1016/j.actatropica.2008.05.021|pmid=18579104}}</ref> widow and recluse species bites rarely have fatal consequences. In addition to the widespread widow and recluse spiders, some spider families found exclusively in remote tropical regions have a lethal neurotoxic venom: the wandering spider in Brazil and the funnel web in Australia. However, due to limited contact between these spiders and humans, deaths have always been rare, and since the introduction of anti-venom in Australia, there have been no funnel web related deaths.<ref name="ReferenceA">{{cite journal|last1=Isbister|first1=GK|last2=Gray|first2=MR|title=Bites by Australian mygalomorph spiders (Araneae, Mygalomorphae), including funnel-web spiders (Atracinae) and mouse spiders (Actinopodidae: Missulena spp).|journal=Toxicon|date=February 2004|volume=43|issue=2|pages=133–40|pmid=15019472|doi=10.1016/j.toxicon.2003.11.009}}</ref>

==Pathophysiology==
{{Main article|Pathophysiology of spider bites}}
A primary concern of the bite of a spider is the effect of its [[venom]]. A spider envenomation occurs whenever a spider injects [[venom]] into the skin. Not all spider bites involve injection of venom, and the amount of venom injected can vary based on the type of spider and the circumstances of the encounter. The mechanical injury from a spider bite is not a serious concern for humans. However, it is generally the toxicity of spider venom that poses the most risk to human beings; several spiders are known to have venom that can cause injury to humans in the amounts that a spider could inject when biting. While venoms are by definition toxic substances, most spiders do not have venom that is directly toxic (in the quantities delivered) to require medical attention and, of those that do, severity is typically mild.

Spider venoms work on one of two fundamental principles; they are either neurotoxic (attacking the nervous system) or necrotic (attacking tissues surrounding the bite). In some cases, the venom affects vital organs and systems. The venoms of the widow spiders, Brazilian wandering spider and Australian funnel-web are neurotoxic. Heart muscle damage is an unusual complication of widow venom that may lead to death.<ref>{{cite journal|last1=Erdur|first1=B|last2=Turkcuer|first2=I|last3=Bukiran|first3=A|last4=Kuru|first4=O|last5=Varol|first5=I|title=Uncommon cardiovascular manifestations after a Latrodectus bite.|journal=The American Journal of Emergency Medicine|date=February 2007|volume=25|issue=2|pages=232–35|pmid=17276832|doi=10.1016/j.ajem.2006.11.005}}</ref> Pulmonary edema, which is fluid accumulation in the lungs, is a feared and potentially serious but uncommon complication of funnel-web venom.<ref name="ReferenceA"/> Recluse and South African sand spider venoms are necrotic. Recluse venom may also cause severe hemolysis (destruction of red blood cells), though this is typically uncommon.<ref>{{cite journal|last1=Manríquez|first1=JJ|last2=Silva|first2=S|title=[Cutaneous and visceral loxoscelism: a systematic review].|journal=Revista Chilena de Infectologia |date=October 2009|volume=26|issue=5|pages=420–32|pmid=19915750}}</ref>

==Diagnosis==
Reliable diagnoses of spider bites require three conditions: first, there should be clinical effects of the bite at the time or soon afterwards, although there are no symptoms universally diagnostic of a spider bite, and bites by some spiders, e.g. ''Loxosceles'' species, may initially be painless; second, the spider should be collected, either at the time of the bite or immediately afterwards; and third, the spider should be identified by an expert arachnologist.<ref name=IsbiWhit04>{{Citation |last1=Isbister |first1=Geoffrey K |last2=White |first2=Julian |date=2004 |title=Clinical consequences of spider bites: recent advances in our understanding |journal=Toxicon |volume=43 |issue=5 |pages=477–92 |doi=10.1016/j.toxicon.2004.02.002 |pmid=15066408 |name-list-style=amp }}</ref><ref name=StubNent16/>

Spider bites are commonly misdiagnosed. A review published in 2016 showed that 78% of 134 published medical case studies of supposed spider bites did not meet the necessary criteria for a spider bite to be verified. In the case of the two genera with the highest reported number of bites, ''[[Loxosceles]]'' and ''[[Latrodectus]]'', spider bites were not verified in over 90% of the reports. Even when verification had occurred, details of the treatment and its effects were often lacking.<ref name=StubNent16/> Unverified bite reports likely represent many other conditions, both infectious and non-infectious, which can be confused with spider bites.<ref>{{cite journal | doi = 10.1636/RSt08-06.1 | last1 = Vetter | first1 = R.S. | year = 2008 | title = Spiders of the genus ''Loxosceles'' (Araneae, Sicariidae): a review of biological, medical and psychological aspects regarding envenomations | journal = The Journal of Arachnology | volume = 36 | pages = 150–63 | s2cid = 7746032 | url = https://www.biodiversitylibrary.org/part/229051 }}</ref> Many of these conditions are far more common and more likely to be the source of necrotic wounds.<ref name=Swanson2005/> An affected person may think that a wound is a spider bite when it is actually an infection with [[methicillin-resistant Staphylococcus aureus|methicillin-resistant ''Staphylococcus aureus'']] (MRSA).<ref>{{cite web|title=Methicillin-resistant Staphylococcus aureus (MRSA) Infections|url=https://www.cdc.gov/mrsa/community/|website=cdc.gov|access-date=15 February 2015|date=September 10, 2013}}</ref>  False reports of spider bites in some cases have led to misdiagnosis and mistreatment, with potentially life-threatening consequences.<ref name="autogenerated1">{{Cite journal | doi = 10.1136/ewjm.173.5.357 | last1 = Vetter | first1 = R. S. | year = 2000 | title = Myth: idiopathic wounds are often due to brown recluse or other spider bites throughout the United States | journal = [[Western Journal of Medicine]] | volume = 173 | issue = 5| pages = 357–58 | pmid=11069881 | pmc = 1071166}}</ref>

==Prevention==
Efforts to prevent bites include clearing clutter and the use of [[pesticide]]s.<ref name=Lancet2011/>

[[Occupational Safety and Health Administration|OSHA]] recommends that workers take following measures to prevent spider bite:
* Wear a long-sleeved shirt, hat, gloves, and boots when handling boxes, firewood, lumber, rocks, etc.
* Inspect and shake out clothing and shoes before getting dressed.
* Use insect repellents, such as [[DEET]] or [[Icaridin|Picaridin]], on clothing and footwear.<ref>{{Cite web|url=https://www.osha.gov/OshDoc/data_Hurricane_Facts/black_widow_spider.pdf|title=Protect yourself! Workers may be exposed to Black Widow Spider|date=October 2005|website=[[Occupational Safety and Health Administration|OSHA]] Fact Sheet|access-date=July 13, 2016}}</ref><ref>{{Cite web|url=https://www.osha.gov/OshDoc/data_Hurricane_Facts/brown_recluse_spider.pdf|title=Protect yourself! Workers may be exposed to Brown Recluse spider|date=October 2015|website=[[Occupational Safety and Health Administration|OSHA]]|access-date=July 13, 2016}}</ref>

==Management==
Most spider bites are harmless and require no specific treatment. Treatment of bites may depend on the type of spider; thus, capture of the spider—either alive, or in a well-preserved condition, is useful.<ref>[http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Spiders Spiders] {{webarchive|url=https://web.archive.org/web/20131029203227/http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Spiders |date=2013-10-29 }}, Retrieved December 1, 2013</ref><ref>[http://dermnetnz.org/arthropods/spider-bites.html Spider bites], Retrieved December 1, 2013</ref>

Treatment of spider bites includes washing the wound with soap and water and ice to reduce inflammation.<ref name=Diaz2007>{{cite journal|last1=Diaz|first1=JH|last2=Leblanc|first2=KE|title=Common spider bites.|journal=American Family Physician|date=15 March 2007|volume=75|issue=6|pages=869–73|pmid=17390599}}</ref> [[Analgesics]] and [[antihistamines]] may be used; however, antibiotics are not recommended unless there is also a [[bacterial infection]] present.<ref name=Diaz2007/> Black widow post-envenomation treatment seeks to control resulting pain and nausea.

In the case of bites by [[widow spider]]s, [[Australian funnel-web spider]]s, or [[Brazilian wandering spider]]s, medical attention should be sought immediately as in some cases the bites of these spiders develop into a [[medical emergency]].<ref>[https://www.nlm.nih.gov/medlineplus/ency/article/002858.htm Spider bites: First aid], Retrieved December 1, 2013</ref><ref>{{cite web|title=Spider Bites|url=http://www.healthdirect.gov.au/spider-bites|website=Health Direct Australia|date=6 October 2020}}</ref> Antivenom is available for severe widow and funnel-web envenomation.<ref name="Lancet2011"/>

===Necrosis===
In almost all cases, recluse bites are self-limited and typically heal without any medical intervention.<ref name=Swanson2005/> Recommendations to limit the extent of damage include elevation and immobilization of the affected limb, application of ice. Both local wound care and [[tetanus prophylaxis]], are simple standards. There is no established treatment for more extensive [[necrosis]]. Many therapies have been used including [[hyperbaric oxygen]], [[dapsone]], antihistamines (e.g., [[cyproheptadine]]), [[antibiotics]], [[dextran]], [[glucocorticoids]], vasodilators, [[heparin]], [[nitroglycerin]], [[electric shock]], [[curettage]], [[surgery|surgical excision]], and [[antivenom]]. None of these treatments conclusively show benefit. Studies have shown surgical intervention is ineffective and may worsen outcome. Excision may delay wound healing, cause [[abscesses]], and lead to objectionable scarring.<ref name="AnnSurg1985-Rees">{{cite journal |vauthors=Rees R, Altenbern D, Lynch J, King L | title = Brown recluse spider bites. A comparison of early surgical excision versus dapsone and delayed surgical excision | journal = Ann Surg | volume = 202 | issue = 5 | pages = 659–63 | year = 1985 | pmid = 4051613 | pmc = 1250983 | doi = 10.1097/00000658-198511000-00020}}</ref>

[[Dapsone]], an antibiotic, is commonly used in the United States and [[Brazil]] for the treatment of necrosis. There have been conflicting reports with some supporting its efficacy and others have suggested it should no longer be used routinely, if at all.<ref name="AmJEmergMed2003-Bryant">{{cite journal |vauthors=Bryant S, Pittman L | title = Dapsone use in Loxosceles reclusa envenomation: is there an indication? | journal = Am J Emerg Med | volume = 21 | issue = 1 | pages = 89–90 | year = 2003 | pmid = 12563594 | doi = 10.1053/ajem.2003.50021}}</ref>

===Antivenom===
Use of [[antivenom]] for severe spider bites may be indicated, especially in the case of neurotoxic venoms.<ref name="pmid19457345">{{cite journal |vauthors=Espino-Solis GP, Riaño-Umbarila L, Becerril B, Possani LD |title=Antidotes against venomous animals: state of the art and prospectives |journal=Journal of Proteomics |volume=72 |issue=2 |pages=183–99 |date=March 2009 |pmid=19457345 |doi=10.1016/j.jprot.2009.01.020 }}</ref> Effective antivenoms exist for ''Latrodectus'', ''Atrax'', and ''Phoneutria'' venom. Antivenom in the United States is in intravenous form but is rarely used, as anaphylactic reaction to the antivenom has resulted in deaths. In Australia, antivenom in intramuscular form was once commonly used, but use has declined. In 2014 some doubt as to antivenom effectiveness has been raised.<ref>{{cite journal|last1=Isbister|first1=GK|last2=Page|first2=CB|last3=Buckley|first3=NA|last4=Fatovich|first4=DM|last5=Pascu|first5=O|last6=MacDonald|first6=SP|last7=Calver|first7=LA|last8=Brown|first8=SG|last9=RAVE|first9=Investigators|title=Randomized controlled trial of intravenous antivenom versus placebo for latrodectism: the second Redback Antivenom Evaluation (RAVE-II) study.|journal=Annals of Emergency Medicine|date=December 2014|volume=64|issue=6|pages=620–8.e2|pmid=24999282|doi=10.1016/j.annemergmed.2014.06.006|hdl=2123/14928|hdl-access=free}}</ref><ref name=IsbiGray03/> In South America an antivenom is available for ''Loxosceles'' bites, and it appears antivenom may be the most promising therapy for recluse bites. However, in experimental trials recluse antivenom is more effective when given early, and patients often do not present for 24 or more hours after envenomation, possibly limiting the effect of such intervention.<ref name="ClinTox2003-Isbister">{{cite journal |vauthors=Isbister G, Graudins A, White J, Warrell D | title = Antivenom treatment in arachnidism | journal = J Toxicol Clin Toxicol | volume = 41 | issue = 3 | pages = 291–300 | year = 2003 | pmid = 12807312 | doi = 10.1081/CLT-120021114| s2cid = 37946164 }}</ref>

==Epidemiology==
Estimating the number of spider bites that occur is difficult as the spider involvement may not be confirmed or identified.<ref name=Diaz2004>{{cite journal|last1=Diaz|first1=JH|title=The global epidemiology, syndromic classification, management, and prevention of spider bites.|journal=The American Journal of Tropical Medicine and Hygiene|date=August 2004|volume=71|issue=2|pages=239–50|pmid=15306718|doi=10.4269/ajtmh.2004.71.2.0700239|doi-access=free}}</ref> Several researchers recommend only evaluating verified bites: those that have an eyewitness to the bite, the spider is brought in, and identified by expert. With "suspected arachnidism" the diagnosis came without a spider positively identified.<ref name=Swanson2005/>

===Africa===
Several ''Latrodectus'' species ([[button spider]]s) live in Africa. South Africa also has six-eyed sand spiders (''[[Hexophthalma]]'' species), whose bite may potentially cause skin necrosis. Physicians are advised that the diagnosis may be difficult without a spider.<ref>{{cite journal |vauthors=Muller GJ, Wium CA, Marks C, Plessis CE, Veale DJ | year = 2012 | title = Spider bite in southern Africa: diagnosis and management | journal = CME | volume = 30 | issue = 10| pages = 382–91 }}</ref>

===Australia===
Bites by the redbacks (''Latrodectus hasselti'') number a few thousand yearly throughout the country. Antivenom use is frequent but declining.<ref name=IsbiGray03>{{cite journal|last1=Isbister|first1=GK|last2=Gray|first2=MR|title=Latrodectism: a prospective cohort study of bites by formally identified redback spiders.|journal=The Medical Journal of Australia|date=21 July 2003|volume=179|issue=2|pages=88–91|pmid=12864719|doi=10.5694/j.1326-5377.2003.tb05442.x|s2cid=25632248}}</ref> Children may have fewer complications from bites.<ref>{{cite journal|last1=Mead|first1=H.J.|last2=Jelinek|first2=G.A.|title=Red-back spider bites to Perth children, 1979–1988|journal=Journal of Paediatrics and Child Health|date=August 1993|volume=29|issue=4|pages=305–08|doi=10.1111/j.1440-1754.1993.tb00518.x|pmid=8373679|s2cid=25640556}}</ref> Funnel web spider bites are few 30–40 per year and 10% requiring intervention. The Sydney funnel web and related species are only on the east coast of Australia.<ref>{{cite journal|last1=Braitberg|first1=G|last2=Segal|first2=L|title=Spider bites – Assessment and management.|journal=Australian Family Physician|date=November 2009|volume=38|issue=11|pages=862–67|pmid=19893831}}</ref><ref name=IsbiGray02/>

===Europe===
In Switzerland about ten to one hundred spider bites occur per one million people per year.<ref>{{cite journal|last1=Nentwig|first1=Wolfgang|last2=Gnädinger|first2=Markus|last3=Fuchs|first3=Joan|last4=Ceschi|first4=Alessandro|title=A two year study of verified spider bites in Switzerland and a review of the European spider bite literature|journal=Toxicon|date=October 2013|volume=73|pages=104–10|doi=10.1016/j.toxicon.2013.07.010|pmid=23872119}}</ref> During epidemics of latrodectism from the European black widow upwards of 150 bites a year were documented.<ref>{{cite journal|last1=Bettini|first1=S|title=Epidemiology of Latrodectism|journal=Toxicon|date=October 1964|volume=2|issue=2|pages=93–102|pmid=14301291|doi=10.1016/0041-0101(64)90009-1}}</ref>

===North America===
The American Association of Poison Control Centers reported that they received calls regarding nearly 10,000 spider bites in 1994.<ref name=Diaz2004/> The spiders of most concern in North America are [[brown recluse spider]]s, with nearly 1,500 bites in 2013<ref name="AAPC 2012">{{cite journal|last1=Mowry|first1=James B.|last2=Spyker|first2=Daniel A.|last3=Cantilena|first3=Louis R.|last4=McMillan|first4=Naya|last5=Ford|first5=Marsha|title=2013 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 31st Annual Report|journal=Clinical Toxicology|date=December 2014|volume=52|issue=10|pages=1032–1283|doi=10.3109/15563650.2014.987397|pmid=25559822|pmc=4782684}}</ref> and [[Latrodectus|black widow spiders]] with 1,800 bites. of which a dozen involved major complications.<ref name="AAPC 2012"/> The native habitat of brown recluse spiders is in the southern and central United States, as far north as [[Iowa]]. Encounters with brown recluse outside this native region are very rare and bites are thought to be suspect.<ref name=Swanson2005/>

===South America===
Numerous spider bites are recorded in Brazil with 5000+ annually. ''Loxosceles'' species are responsible for the majority of reports. Accidents are concentrated in the southern state of Parana with rates as high as 1 per 1,000 people.<ref>{{cite journal|last1=Marques-da-Silva|first1=E.|last2=Souza-Santos|first2=R.|last3=Fischer|first3=M. L.|last4=Rubio|first4=G. B. G.|title=''Loxosceles'' spider bites in the state of Paraná, Brazil: 1993–2000|journal=Journal of Venomous Animals and Toxins Including Tropical Diseases|date=2006|volume=12|issue=1|doi=10.1590/S1678-91992006000100009|doi-access=free}}</ref> Bite from ''Phoneutria'' (Brazilian wandering spider) number in the thousands with most being mild. Severe effects are noted in 0.5% of cases, mostly in children.<ref>{{cite journal|last1=Bucaretchi|first1=Fábio|last2=Deus Reinaldo|first2=Cláudia Regina de|last3=Hyslop|first3=Stephen|last4=Madureira|first4=Paulo Roberto|last5=De Capitani|first5=Eduardo Mello|last6=Vieira|first6=Ronan José|title=A clinico-epidemiological study of bites by spiders of the genus ''Phoneutria''|journal=Revista do Instituto de Medicina Tropical de São Paulo|date=February 2000|volume=42|issue=1|doi=10.1590/S0036-46652000000100003|pmid=10742722|pages=17–21|doi-access=free}}</ref>

==History==
Recorded treatment from the 1890s for spider bites in general was rubbing in [[tobacco juice]] to the bitten skin,<ref>{{cite wikisource |first=Wilhelmina |last=Rawson |wslink=Australian enquiry book of household and general information |title=Australian Enquiry Book of Household and General Information |year=1894 |page=165 <!-- |wspage=169 not working yet--> |publisher=Pater & Knapton, Printers & Publishers |scan=Page:Australian enquiry book of household and general information.djvu/169}}</ref> similar to some of the traditional uses of the tobacco plant for various bites and stings from Central and South America.{{cn|date=June 2020}} Wild dancing and music was the cure for [[tarantism]]—the frenzy was believed to arise from the bite of a spider.<ref>{{cite web|title=Tarantism: Form of Hysteria|url=http://www.britannica.com/EBchecked/topic/583346/tarantism|publisher=Encyclopædia Britannica|access-date=22 March 2015}}</ref> An antivenom was developed against wolf spiders in Brazil and used for decades. Wolf spiders have since been exonerated—they never caused illness.<ref>{{cite web|last1=Crawford|first1=Rod|title=Myths, Misconceptions, and Superstitions About Spiders|url=http://www.burkemuseum.org/spidermyth/|website=Burke Museum|publisher=University of Washington|access-date=22 March 2015}}</ref>

==See also==
* [[ArachnoServer]] database
* [[Raventoxin]]
* [[Vanillotoxin]]

==References==
{{Reflist}}

== External links ==
{{Medical resources
|  DiseasesDB      =12299
|  ICD10           = {{ICD10|T|14|1|t|08}}{{·}}{{ICD10|T|63|3|t|51}}<br />{{nowrap|W57 (nonvenomous)}}<br />{{nowrap|X21 (venomous)}}
|  ICD9            = {{ICD9|989.5}}{{·}}{{ICD9|E905.1}}{{·}}{{ICD9|E906.4}}
|  ICDO            =
|  OMIM            =
|  MedlinePlus     = 002858
|  eMedicineSubj   = article
|  eMedicineTopic  = 772484
}}
* [http://www.mja.com.au/public/issues/182_08_180405/isb10564_fm.html Medical Journal of Australia article gives statistics on the most frequent biters and the most serious bites.]
* [https://www.cdc.gov/niosh/topics/spiders/ CDC – Venomous Spiders – NIOSH Workplace Safety and Health Topic]

{{Spider nav}}
{{General injuries}}
{{Poisoning and toxicity}}
{{Animal bites and stings}}
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{{DEFAULTSORT:Spider Bite}}
[[Category:Arthropod attacks]]
[[Category:Parasitic infestations, stings, and bites of the skin]]
[[Category:Toxic effects of venomous animals]]
[[Category:Spiders and humans]]