Spider bite

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Bite caused by a spider

title: "Spider bite" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["arthropod-attacks", "parasitic-infestations,-stings,-and-bites-of-the-skin", "toxic-effects-of-venomous-animals", "spiders-and-humans"] description: "Bite caused by a spider" topic_path: "general/arthropod-attacks" source: "https://en.wikipedia.org/wiki/Spider_bite" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Bite caused by a spider ::

::data[format=table title="Infobox medical condition (new)"]

FieldValue
nameSpider bite
imageBlack Wishbone.jpg
captionChelicerae of a black wishbone (nemesiid) spider, a mygalomorph
fieldEmergency medicine
complicationsEnvenomation
causesSpiders
::

| name = Spider bite | synonyms = | image = Black Wishbone.jpg | caption = Chelicerae of a black wishbone (nemesiid) spider, a mygalomorph | pronounce = | field = Emergency medicine | symptoms = | complications = Envenomation | onset = | duration = | types = | causes = Spiders | risks = | diagnosis = | differential = | prevention = | treatment = | medication = | prognosis = | frequency = | deaths =

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. Most bites result in mild symptoms around the area of the bite.

Most spiders do not cause bites that are of importance. Symptoms may include pain which may be at the bite or involve the chest and abdomen, sweating, muscle cramps and vomiting among others. Headaches, vomiting and a mild fever may also occur. and South American wandering spider.

Efforts to prevent bites include clearing clutter and the use of pesticides.

Spider bites may be overdiagnosed or misdiagnosed. 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. While necrosis has been attributed to the bites of a number of spiders, good evidence only supports this for recluse spiders.

Signs and symptoms

::figure[src="https://upload.wikimedia.org/wikipedia/commons/4/47/BrownRecuse1.jpg" caption="A Brazilian man 31 hours after having been bitten on his face by a [[recluse spider"] ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/e/e8/BrownRecluse2_-_scarring_after_spider_bite.jpg" caption="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 minutes while pain from envenomating spider bites may last for longer than 24 hours. Bleeding also may occur with a bite. Signs of a bacterial infection due to a spider bite occur infrequently (0.9%).

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. Activation of the sympathetic nervous system can lead to sweating, high blood pressure and gooseflesh.

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. Rarely, bites may cause widespread symptoms, with occasional fatalities.

There are a few spiders that can bite human skin and cause a skin reaction, but spiders are blamed for many more reactions. In particular the misdiagnosis of infections and other skin ailments are commonly attributed to brown recluses.

::data[format=table title="Spiders associated with skin reactions"]

Scientific nameCommon nameVenomReaction
Lampona spp{{cite journallast1=Isbisterfirst2=M. R.last2=Gray
Loxosceles sppBrown recluseSphingomyelinaseNecrosis
Cheiracanthium sppSacLipaseRedness
Tegenaria agrestisHoboRedness
Lycosidae sppWolfRedness, itching
::

Cause

Main article: List of medically significant spider bites

Spiders do not feed on humans and typically bites occur as a defense mechanism. This can occur from unintentional contact or trapping of the spider.

Medically significant spider venoms include various combinations and concentrations of 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 snake and scorpion envenomation, 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.

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. Pulmonary edema, which is fluid accumulation in the lungs, is a feared and potentially serious but uncommon complication of funnel-web venom. 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.

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.

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. Many of these conditions are far more common and more likely to be the source of necrotic wounds. False reports of spider bites in some cases have led to misdiagnosis and mistreatment, with potentially life-threatening consequences.

Prevention

Efforts to prevent bites include clearing clutter and the use of pesticides.

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 Picaridin, on clothing and footwear.

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.

Treatment of spider bites includes washing the wound with soap and water and ice to reduce inflammation. Analgesics and antihistamines may be used; however, antibiotics are not recommended unless there is also a bacterial infection present. Black widow post-envenomation treatment seeks to control resulting pain and nausea.

In the case of bites by widow spiders, Australian funnel-web spiders, or Brazilian wandering spiders, medical attention should be sought immediately as in some cases the bites of these spiders develop into a medical emergency. Antivenom is available for severe widow and funnel-web envenomation.

Necrosis

In almost all cases, recluse bites are self-limited and typically heal without any medical intervention.

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.

Antivenom

Use of antivenom for severe spider bites may be indicated, especially in the case of neurotoxic venoms. 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.

Epidemiology

Estimating the number of spider bites that occur is difficult as the spider involvement may not be confirmed or identified. 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.

Africa

Several Latrodectus species (button spiders) 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.

Australia

Bites by the redbacks (Latrodectus hasselti) number a few thousand yearly throughout the country. Antivenom use is frequent but declining. Children may have fewer complications from bites. 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.

Europe

In Switzerland about ten to one hundred spider bites occur per one million people per year. During epidemics of latrodectism from the European black widow upwards of 150 bites a year were documented.

North America

The American Association of Poison Control Centers reported that they received calls regarding nearly 10,000 spider bites in 1994. and black widow spiders with 1,800 bites. of which a dozen involved major complications. 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.

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. 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.

History

Recorded treatment from the 1890s for spider bites in general was rubbing in tobacco juice to the bitten skin, similar to some of the traditional uses of the tobacco plant for various bites and stings from Central and South America. Wild dancing and music was the cure for tarantism—the frenzy was believed to arise from the bite of a spider. An antivenom was developed against wolf spiders in Brazil and used for decades. Wolf spiders have since been exonerated—they never caused illness.

References

References

  1. (10 December 2011). "Spider bite.". Lancet.
  2. (2006). "Andrews' Diseases of the Skin: clinical Dermatology". Saunders Elsevier.
  3. (18 April 2005). "Funnel-web spider bite: a systematic review of recorded clinical cases.". The Medical Journal of Australia.
  4. (July 1997). "The dancing plague: a public health conundrum.". Public Health.
  5. "Global Family Doctor".
  6. (November 2002). "A prospective study of 750 definite spider bites, with expert spider identification". QJM.
  7. (Summer 2011). "The treatment of black widow spider envenomation with antivenin latrodectus mactans: a case series". The Permanente Journal.
  8. (5 August 2002). "Convenient culprit: Myths surround the brown recluse spider". American Medical Association.
  9. (June 2013). "Spider envenomation in North America.". Critical Care Nursing Clinics of North America.
  10. (2017-05-01). "NOT RECLUSE – A Mnemonic Device to Avoid False Diagnoses of Brown Recluse Spider Bites". JAMA Dermatology.
  11. (2014). "A phoenix of clinical toxinology: White-tailed spider (Lampona spp.) bites. A case report and review of medical significance". Toxicon.
  12. (2014). "Verified spider bites in Oregon (USA) with the intent to assess hobo spider venom toxicity". Toxicon.
  13. Lucas, Sylvia M.. (December 2015). "The history of venomous spider identification, venom extraction methods and antivenom production: a long journey at the Butantan Institute, São Paulo, Brazil". Journal of Venomous Animals and Toxins Including Tropical Diseases.
  14. (5 November 2004). "Australian Wolf Spider Bites (Lycosidae): Clinical Effects and Influence of Species on Bite Circumstances". Journal of Toxicology: Clinical Toxicology.
  15. (February 24, 2012). "Workplace Safety & Health Topics Venomous Spiders".
  16. "Spider Bite First Aid". firstaidkits.org.
  17. (August 2008). "Epidemiology of scorpionism: a global appraisal.". Acta Tropica.
  18. (February 2004). "Bites by Australian mygalomorph spiders (Araneae, Mygalomorphae), including funnel-web spiders (Atracinae) and mouse spiders (Actinopodidae: Missulena spp).". Toxicon.
  19. (February 2007). "Uncommon cardiovascular manifestations after a Latrodectus bite.". The American Journal of Emergency Medicine.
  20. (October 2009). "[Cutaneous and visceral loxoscelism: a systematic review].". Revista Chilena de Infectologia.
  21. (2004). "Clinical consequences of spider bites: recent advances in our understanding". Toxicon.
  22. (2008). "Spiders of the genus ''Loxosceles'' (Araneae, Sicariidae): a review of biological, medical and psychological aspects regarding envenomations". The Journal of Arachnology.
  23. (2000). "Myth: idiopathic wounds are often due to brown recluse or other spider bites throughout the United States". [[Western Journal of Medicine]].
  24. (October 2005). "Protect yourself! Workers may be exposed to Black Widow Spider".
  25. (October 2015). "Protect yourself! Workers may be exposed to Brown Recluse spider".
  26. [http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Spiders Spiders] {{webarchive. link. (2013-10-29 , Retrieved December 1, 2013)
  27. [http://dermnetnz.org/arthropods/spider-bites.html Spider bites], Retrieved December 1, 2013
  28. (15 March 2007). "Common spider bites.". American Family Physician.
  29. [https://www.medlineplus.gov/ency/article/002858.htm Spider bites: First aid], Retrieved December 1, 2013
  30. (6 October 2020). "Spider Bites".
  31. (2003). "Dapsone use in Loxosceles reclusa envenomation: is there an indication?". Am J Emerg Med.
  32. (March 2009). "Antidotes against venomous animals: state of the art and prospectives". Journal of Proteomics.
  33. (December 2014). "Randomized controlled trial of intravenous antivenom versus placebo for latrodectism: the second Redback Antivenom Evaluation (RAVE-II) study.". Annals of Emergency Medicine.
  34. (2003). "Antivenom treatment in arachnidism". J Toxicol Clin Toxicol.
  35. (August 2004). "The global epidemiology, syndromic classification, management, and prevention of spider bites.". The American Journal of Tropical Medicine and Hygiene.
  36. (2012). "Spider bite in southern Africa: diagnosis and management". CME.
  37. (21 July 2003). "Latrodectism: a prospective cohort study of bites by formally identified redback spiders.". The Medical Journal of Australia.
  38. (August 1993). "Red-back spider bites to Perth children, 1979–1988". Journal of Paediatrics and Child Health.
  39. (November 2009). "Spider bites – Assessment and management.". Australian Family Physician.
  40. (October 2013). "A two year study of verified spider bites in Switzerland and a review of the European spider bite literature". Toxicon.
  41. (October 1964). "Epidemiology of Latrodectism". Toxicon.
  42. (December 2014). "2013 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 31st Annual Report". Clinical Toxicology.
  43. (2006). "''Loxosceles'' spider bites in the state of Paraná, Brazil: 1993–2000". Journal of Venomous Animals and Toxins Including Tropical Diseases.
  44. (February 2000). "A clinico-epidemiological study of bites by spiders of the genus ''Phoneutria''". Revista do Instituto de Medicina Tropical de São Paulo.
  45. Rawson, Wilhelmina. (1894). "Australian Enquiry Book of Household and General Information". Pater & Knapton, Printers & Publishers.
  46. "Tarantism: Form of Hysteria". Encyclopædia Britannica.
  47. "Myths, Misconceptions, and Superstitions About Spiders". University of Washington.

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