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Brown Recluse Spider Envenomation

  • Author: Thomas C Arnold, MD, FAAEM, FACMT; Chief Editor: Joe Alcock, MD, MS  more...
 
Updated: Feb 24, 2016
 

Background

In the United States, reports of severe envenomations by brown spiders began to appear in the late 1800s, and today, in endemic areas, brown spiders continue to be of significant clinical concern. See the current distribution map below.

Complete distribution range of wild and domestic L Complete distribution range of wild and domestic Loxosceles reclusa (brown recluse spider). Courtesy of Wikimedia Commons (By ReliefUSA_map.gif: Public domain, U.S. government derivative work: Bob the Wikipedian).

Of the 13 species of Loxosceles in the United States, at least 5 have been associated with necrotic arachnidism. Loxosceles reclusa, or the brown recluse spider, is the spider most commonly responsible for this injury.

Typical appearance of a male brown recluse spider. Typical appearance of a male brown recluse spider. Photo contributed by Michael Cardwell, Victorville, Calif.
Spider envenomations, brown recluse. Close-up imag Spider envenomations, brown recluse. Close-up image of dorsal violin-shaped pattern. Photo contributed by Michael Cardwell, Victorville, Calif.

Dermonecrotic arachnidism refers to the local skin and tissue injury noted with this envenomation. Loxoscelism is the term used to describe the systemic clinical syndrome caused by envenomation from the brown spiders.

Dermonecrotic arachnidism represents a local cutan Dermonecrotic arachnidism represents a local cutaneous injury with tissue loss and necrosis.

See Arthropod Envenomation: From Benign Bites to Serious Stings and Venomous Spider Bites: Keys to Diagnosis and Treatment, Critical Images slideshows, for help identifying and treating various envenomations.

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Pathophysiology

Brown recluse spider bites can cause significant cutaneous injury with tissue loss and necrosis. Less frequently, more severe reactions develop, including systemic hemolysis, coagulopathy, renal failure, and, rarely, death.

Brown recluse venom, like many of the other brown spider venoms, is cytotoxic and hemolytic. It contains at least 8 components, including enzymes such as hyaluronidase, deoxyribonuclease, ribonuclease, alkaline phosphatase, and lipase. Sphingomyelinase D is thought to be the protein component responsible for most of the tissue destruction and hemolysis caused by brown recluse spider envenomation. The intense inflammatory response mediated by arachidonic acid, prostaglandins, and chemotactic infiltration of neutrophils is amplified further by an intrinsic vascular cascade involving the mediator C-reactive protein and complement activation. Laboratory studies have shown a decrease in hemolysis from brown recluse venom in the presence of complement inhibitors.[1] These and other factors contribute to the local and systemic reactions of necrotic arachnidism.

Although numerous cases of cutaneous and viscerocutaneous reactions have been attributed to spiders of the genus Loxosceles, confirming the identity of the envenomating arachnid is difficult and rarely accomplished.

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Epidemiology

Frequency

United States

Although various species of Loxosceles are found throughout the world, L reclusa is found in the United States from the East to the West Coast, with predominance in the south. Recently, reports of persons with "spider bites" presenting to emergency departments have reached near urban legend proportions, prompting many physicians to question the diagnosis of a brown recluse bite in nonendemic areas.[2, 3, 4] The list of conditions that can present in a similar fashion to that of a brown recluse spider envenomation is extensive. A more likely explanation for this epidemic of spider bites is in fact community-acquired methicillin-resistant Staphylococcus aureus (MRSA) skin infections.[5] The 2014 Annual Report of the American Association of Poison Control Centers recorded 1330 individual exposures to brown recluse spiders that year.[6]

Age

Systemic involvement, although uncommon, occurs more frequently in children than in adults.[7]

See the distribution map below.

Complete distribution range of wild and domestic L Complete distribution range of wild and domestic Loxosceles reclusa (brown recluse spider). Courtesy of Wikimedia Commons (By ReliefUSA_map.gif: Public domain, U.S. government derivative work: Bob the Wikipedian).

 

Content.

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Mortality/Morbidity

Data regarding mortality rates are not reliable because diagnostic tests to detect brown recluse venom in tissue are not readily available.

Although deaths have been attributed to presumed brown recluse envenomation, severe outcomes are rare.[8] Typical cases involve only local soft tissue destruction. The 2014 Annual Report of the American Association of Poison Control Centers recorded 275 minor outcomes, 218 moderate outcomes, 11 major outcomes, and no deaths.[6]

In South America, the more potent venom of the species Loxosceles laeta is responsible for several deaths each year.

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Contributor Information and Disclosures
Author

Thomas C Arnold, MD, FAAEM, FACMT Professor and Chairman, Department of Emergency Medicine, Section of Clinical Toxicology, Louisiana State University Health Sciences Center-Shreveport; Medical Director, Louisiana Poison Center

Thomas C Arnold, MD, FAAEM, FACMT is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Medical Toxicology, Louisiana State Medical Society, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

John T VanDeVoort, PharmD Regional Director of Pharmacy, Sacred Heart and St Joseph's Hospitals

John T VanDeVoort, PharmD is a member of the following medical societies: American Society of Health-System Pharmacists

Disclosure: Nothing to disclose.

James Steven Walker, DO, MS Clinical Professor of Surgery, Department of Surgery, University of Oklahoma College of Medicine

James Steven Walker, DO, MS is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, American Osteopathic Association

Disclosure: Nothing to disclose.

Chief Editor

Joe Alcock, MD, MS Associate Professor, Department of Emergency Medicine, University of New Mexico Health Sciences Center

Joe Alcock, MD, MS is a member of the following medical societies: American Academy of Emergency Medicine

Disclosure: Nothing to disclose.

Additional Contributors

Robert L Norris, MD Professor, Department of Emergency Medicine, Stanford University Medical Center

Robert L Norris, MD is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine, International Society of Toxinology, American Medical Association, California Medical Association, Wilderness Medical Society

Disclosure: Nothing to disclose.

References
  1. Gehrie EA, Nian H, Young PP. Brown Recluse spider bite mediated hemolysis: clinical features, a possible role for complement inhibitor therapy, and reduced RBC surface glycophorin A as a potential biomarker of venom exposure. PLoS One. 2013. 8(9):e76558. [Medline]. [Full Text].

  2. Vetter RS. Arachnids misidentified as brown recluse spiders by medical personnel and other authorities in North America. Toxicon. 2009 Sep 15. 54(4):545-7. [Medline].

  3. Vetter RS, Barger DK. An infestation of 2,055 brown recluse spiders (Araneae: Sicariidae) and no envenomations in a Kansas home: implications for bite diagnoses in nonendemic areas. J Med Entomol. 2002 Nov. 39(6):948-51. [Medline].

  4. Vetter RS, Bush SP. Reports of presumptive brown recluse spider bites reinforce improbable diagnosis in regions of North America where the spider is not endemic. Clin Infect Dis. 2002 Aug 15. 35(4):442-5. [Medline].

  5. Miller LG, Spellberg B. Spider bites and infections caused by community-associated methicillin-resistant Staphylococcus aureus. Surg Infect. 2004 Fall. 5(3):321-2. [Medline].

  6. Mowry JB, Spyker DA, Brooks DE, McMillan N, Schauben JL. 2014 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 32nd Annual Report. Clin Toxicol (Phila). 2015 Dec. 53 (10):962-1147. [Medline]. [Full Text].

  7. McDade J, Aygun B, Ware RE. Brown recluse spider (Loxosceles reclusa) envenomation leading to acute hemolytic anemia in six adolescents. J Pediatr. 2010 Jan. 156(1):155-7. [Medline].

  8. Rosen JL, Dumitru JK, Langley EW, Meade Olivier CA. Emergency Department Death From Systemic Loxoscelism. Ann Emerg Med. 2012 Feb 1. [Medline].

  9. McGlasson DL, Green JA, Stoecker WV, Babcock JL, Calcara DA. Duration of Loxosceles reclusa venom detection by ELISA from swabs. Clin Lab Sci. 2009 Fall. 22(4):216-22. [Medline].

  10. Graham WR Jr. Adverse effects of dapsone. Int J Dermatol. 1975 Sep. 14(7):494-500. [Medline].

  11. Phillips S, Kohn M, Baker D, Vander Leest R, Gomez H, McKinney P, et al. Therapy of brown spider envenomation: a controlled trial of hyperbaric oxygen, dapsone, and cyproheptadine. Ann Emerg Med. 1995 Mar. 25(3):363-8. [Medline].

  12. King LE Jr, Rees RS. Dapsone treatment of a brown recluse bite. JAMA. 1983 Aug 5. 250(5):648. [Medline].

  13. Burton KG. Nitroglycerine patches for brown recluse spider bites. Am Fam Physician. 1995 May 1. 51(6):1401. [Medline].

  14. Lowry BP, Bradfield JF, Carroll RG, Brewer K, Meggs WJ. A controlled trial of topical nitroglycerin in a New Zealand white rabbit model of brown recluse spider envenomation. Ann Emerg Med. 2001 Feb. 37(2):161-5. [Medline].

  15. Maynor ML, Moon RE, Klitzman B, Fracica PJ, Canada A. Brown recluse spider envenomation: a prospective trial of hyperbaric oxygen therapy. Acad Emerg Med. 1997 Mar. 4(3):184-92. [Medline].

  16. Hobbs GD, Anderson AR, Greene TJ, Yealy DM. Comparison of hyperbaric oxygen and dapsone therapy for loxosceles envenomation. Acad Emerg Med. 1996 Aug. 3(8):758-61. [Medline].

  17. Carlton PK Jr. Brown recluse spider bite? Consider this uniquely conservative treatment. J Fam Pract. 2009 Feb. 58(2):E1-6. [Medline].

  18. de Roodt AR, Estevez-Ramírez J, Litwin S, Magaña P, Olvera A, Alagón A. Toxicity of two North American Loxosceles (brown recluse spiders) venoms and their neutralization by antivenoms. Clin Toxicol (Phila). 2007 Sep. 45(6):678-87. [Medline].

 
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Classic finding of a vesicle with surrounding erythema at 24 hours following brown recluse envenomation. Photo by Thomas Arnold, MD.
Illustration of a brown recluse spider with the fiddle displayed prominently on its dorsum.
Spider envenomations, brown recluse. Envenomation site on inner thigh untreated at 1 week. Photo by Thomas Arnold, MD.
Typical appearance of a male brown recluse spider. Photo contributed by Michael Cardwell, Victorville, Calif.
Female brown recluse with size scale. Photo contributed by Michael Cardwell, Victorville, Calif.
Spider envenomations, brown recluse. Close-up image of dorsal violin-shaped pattern. Photo contributed by Michael Cardwell, Victorville, Calif.
Spider bite, brown recluse. Within an hour, the bite area swelled to the size of a quarter. The area turned blue and dark red by the evening of the first day, exceeding the boundaries of a circle drawn around the area of initial swelling by the patient's physician. Courtesy of Dale Losher.
Spider bite, brown recluse. The third day after the bite. The skin continues to die. Courtesy of Dale Losher.
Spider bite, brown recluse. Another view of the wound 3 days after the bite. Courtesy of Dale Losher.
Spider bite, brown recluse. Nine days after the bite. The patient endured 8 days with an open wound to drain the spider's toxins and needed intravenous antibiotics and pain medication almost 24 hours a day. Courtesy of Dale Losher.
Spider bite, brown recluse. Eleven days after the bite. A 5-inch wide area of dead tissue was excised, necessitating skin grafting. Courtesy of Dale Losher.
Spider bite, brown recluse. Waiting to see skin graft results 38 days after the bite. Courtesy of Dale Losher.
Spider bite, brown recluse. Skin graft results 38 days after the bite. Courtesy of Dale Losher.
Spider bite, brown recluse. View of healed wound approximately 10 months after bite. Courtesy of Dale Losher.
Dermonecrotic arachnidism represents a local cutaneous injury with tissue loss and necrosis.
Brown recluse spider. Courtesy of US Centers for Disease Control and Prevention.
Brown recluse spider. Courtesy of US Centers for Disease Control and Prevention.
Complete distribution range of wild and domestic Loxosceles reclusa (brown recluse spider). Courtesy of Wikimedia Commons (By ReliefUSA_map.gif: Public domain, U.S. government derivative work: Bob the Wikipedian).
 
 
 
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