Brown Recluse Spider Envenomation 

  • Author: Thomas C Arnold, MD, FAAEM, FACMT; Chief Editor: Rick Kulkarni, MD   more...
 
Updated: May 21, 2010
 

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.

Of the 13 species of Loxosceles in the United States, at least 5 have been associated with necrotic arachnidism. Loxosceles reclusus, 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 imagSpider 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 cutanDermonecrotic arachnidism represents a local cutaneous injury with tissue loss and necrosis.
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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. 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 reclusus 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. 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.[1]

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. Typical cases involve only local soft tissue destruction.
  • In South America, the more potent venom of the species Loxosceles laeta is responsible for several deaths each year.

Age

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

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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 School of Medicine in Shreveport; Medical Director, Louisiana Poison Control 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, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

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

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

Disclosure: Nothing to disclose.

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, and American Osteopathic Association

Disclosure: Nothing to disclose.

John D Halamka, MD, MS  Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD  Attending Physician, Department of Emergency Medicine, Cambridge Health Alliance, Division of Emergency Medicine, Harvard Medical School

Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: WebMD Salary Employment

References

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  8. Dyachenko P, Ziv M, Rozenman D. Epidemiological and clinical manifestations of patients hospitalized with brown recluse spider bite. J Eur Acad Dermatol Venereol. Oct 2006;20(9):1121-5. [Medline].

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

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

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

  12. 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. Feb 2001;37(2):161-5. [Medline].

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  14. 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. Mar 1995;25(3):363-8. [Medline].

  15. Rees R, Campbell D, Rieger E, King LE. The diagnosis and treatment of brown recluse spider bites. Ann Emerg Med. Sep 1987;16(9):945-9. [Medline].

  16. Sams HH, Hearth SB, Long LL, Wilson DC, Sanders DH, King LE. Nineteen documented cases of Loxosceles reclusa envenomation. J Am Acad Dermatol. Apr 2001;44(4):603-8. [Medline].

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

  18. 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. Nov 2002;39(6):948-51. [Medline].

  19. 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. Aug 15 2002;35(4):442-5. [Medline].

  20. Wille RC, Morrow JD. Case report: dapsone hypersensitivity syndrome associated with treatment of the bite of a brown recluse spider. Am J Med Sci. Oct 1988;296(4):270-1. [Medline].

  21. Wright SW, Wrenn KD, Murray L, Seger D. Clinical presentation and outcome of brown recluse spider bite. Ann Emerg Med. Jul 1997;30(1):28-32. [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.
 
 
 
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