The document summarizes information about recluse and widow spider bites. It discusses the various Loxosceles and Latrodectus species found in North and South America. For recluse bites, minor symptoms include edema and erythema while cutaneous symptoms involve dermal effects. Systemic loxoscelism can cause rash, fever, organ damage and disseminated intravascular coagulation. Effective treatments include wound care, analgesics and blood products. Dapsone has mixed evidence and hyperbaric oxygen is not beneficial. For widow bites, symptoms stem from venom's acetylcholine effects and include pain, sweating and muscle issues. Analgesics and benzodiazepines are effective treatments while

1. Spider Bites that aren’t MRSA
Widows and Recluses
Justin Hensley, MD
Assistant Professor of Emergency Medicine
Texas A&M Health Science Center/Christus Spohn

2. Disclosures
• None

4. Recluse Spiders
 100 species found nearly
worldwide
 80% Western Hemisphere
 Mostly temperate and tropical
areas
 Synanthropic
Swanson, DL., Vetter, RS. Loxoscelism. Clinics in Dermatology. 2006 May-Jun;24(3):213-21.
Vetter, RS, Isbister GK. Medical aspects of spider bites. Annual Review of Entomology. 2008;53:409-29.
• Attics
• Stored clothing
• Boxes

5. Recluse Web
http://brown-recluse-spiders.net/spider_web.htm

6. Loxosceles spp
• Brown Recluse-Loxosceles reclusa
• Texas Recluse-Loxosceles devia
• Big Bend Recluse-Loxosceles blanda
• Apache Recluse-Loxosceles apachea
• Desert Recluse-Loxosceles deserta
• Arizona Recluse-Loxosceles arizonica

7. Loxosceles
Vetter, RS, Isbister GK. Medical aspects of spider bites. Annual Review of Entomology. 2008;53:409-29.

8. Eyes
http://www.alexanderwild.com/Insects/Amazing-Arachnids/10458708_pkHZ7z#!i=1468329946&k=V5DVrbX

9. Fiddleback
http://www.tpwd.state.tx.us/outdoor-learning/hunter-education/online-course/preparation-and-survival/bites-and-stings

10. Arizona
http://bugguide.net/node/view/380945/bgimage

11. Brown
http://www.arachnologyatjunction.com/14.html

12. Big Bend
http://www.arachnologyatjunction.com/14.html

13. Apache
http://bugguide.net/node/view/717100/bgimage

14. Desert
http://bugguide.net/node/view/424379/bgimage

15. Texas
http://bugguide.net/node/view/594647/bgimage

16. Loxoscelism
 Bites accidental
 First reported case of
loxoscelism was in 1872
 Venom has multiple components
 Sphingomyelinase D
Vetter, RS, Isbister GK. Medical aspects of spider bites. Annual Review of Entomology. 2008;53:409-29.
• Minor
• Cutaneous
• Systemic

17. Caveness W. Insect bite complicated by fever. Nashville Journal of Medicine and Surgery. 1872;10:333.

18. Minor Loxoscelism
• Edema
• Erythema
Vetter, RS, Isbister GK. Medical aspects of spider bites. Annual Review of Entomology. 2008;53:409-29.

19. Cutaneous Loxoscelism
Vetter, RS. Spiders of the genus Loxosceles (Araneae, Sicariidae): a review of biological, medical and psychological aspects regarding envenomations . The Journal of
Arachnology. 2008 36:150–163.
Anderson, RJ, Campoli, J, Johar, SK, Schumacher, KA, Allison, EJ. Suspected brown recluse envenomation: A case report and review of different treatment modalities. Journal
of Emergency Medicine. 2011;41(2):31-37.
Isbister GK, Fan HW. Spider bite. Lancet. 2011 Dec 10;378(9808):2039-47
Swanson, DL., Vetter, RS. Loxoscelism. Clinics in Dermatology. 2006 May-Jun;24(3):213-21.
• Dermal Edema
• Endothelial thickening
• Vasodilation
• Leukocyte infiltration
• Coagulation
• Hemorrhage

21. Systemic Loxoscelism
• Rash
– Petechial or morbilliform
• Fever
• Malaise
• Nausea
• Vomiting
• Hemolysis
• Myonecrosis
– Acute renal failure
• Disseminated intravascular coagulation
• Complement mediated
• Direct toxin effect
Vetter, RS, Isbister GK. Medical aspects of spider bites. Annual Review of Entomology. 2008;53:409-29.

22. Treatments
Effective
• Cold compresses (RICE)
• Tetanus
• Symptomatic treatment
– Antihistamines
– Analgesics
• Wound Care
• Blood products
– Systemic
Less Effective
• Heat Packs
• Hyperbaric Oxygen
• Nitroglycerin
• Steroids
• Electric Shock
• Early surgical excision
• Dapsone
Rosen JL, Dumitru JK, Langley EW, Meade Olivier CA. Emergency department death from systemic loxoscelism. Annals of Emergency Medicine. 2012 Oct;60(4):439-41.
Isbister GK, Fan HW. Spider bite. Lancet. 2011 Dec 10;378(9808):2039-47.
Vetter, RS, Isbister GK. Medical aspects of spider bites. Annual Review of Entomology. 2008;53:409-29.
Anderson, RJ, Campoli, J, Johar, SK, Schumacher, KA, Allison, EJ. Suspected brown recluse envenomation: A case report and review of different treatment modalities. Journal
of Emergency Medicine. 2011;41(2):31-37.

23. Probably Shouldn’t Do
• Hyperbaric Oxygen
– May help lesions that are not
healing (and are unclassified)
Maynor ML, Abt L, Osborne PD. Brown recluse spider bites: beneficial effects of hyperbaric oxygen. J
Hyperb Med 1992;7:89–102.
– Not beneficial to pigs or rabbits
Svendsen FJ. Treatment of clinically diagnosed brown recluse spider bites with hyperbaric oxygen: a
clinical observation. J Ark Med Soc 1986;83:199 - 204.
Phillips S, Kohn M, Baker D, et al. Therapy of brown spider envenomation: a controlled trial of
hyperbaric oxygen, dapsone, and cyproheptadine. Ann Emerg Med 1995;25:363- 8.
Hobbs GD, Anderson AR, Greene TJ, Yealy DM. Comparison of hyperbaric oxygen and dapsone
therapy for Loxosceles envenomation. Acad Emerg Med 1996;3:758 - 61.
• Steroids
– May help systemic
symptoms
Anderson PC. Loxoscelism threatening pregnancy: five cases. Am J Obstet
Gynecol 1991;165:1454 - 6.
– No help for ulcers
Dillaha CJ, Jansen GT, Honeycutt WM, Hayden CR. The gangrenous bite of the
brown spider in Arkansas. J Ark Med Soc 1963;60:91.

24. Don’t Do
• Heat Packs
– Worsen ulceration and necrosis
King, LE. Brown recluse spider bites: keep cool. JAMA, 254 (1983), pp. 2895–2896
• Topical Nitroglycerin
– Theoretically vasodilation
may lessen necrosis
– Does not help rabbits,
may increase systemic
effects
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. Annals of Emergency Medicine
2001;372:161–5.

25. Don’t Do
• Electric Shock
– Doesn’t help
Barrett SM, Romine-Jenkins M, Fisher DE. Dapsone or electric shock therapy of brown recluse spider
envenomation? Ann Emerg Med 1994;24:21- 5.
– Unless done late?
Osborn CD. Treatment of spider bites by high voltage direct current.J Okla State Med Assoc
1991;84:257 - 60.
• Surgical Excision
– Early surgery increases
inflammation and may worsen
venom effects
Rees RS, Altenbern DP, Lynch JB, King LE. Brown recluse spider bites. A comparison of early surgical
excision versus dapsone and delayed surgical excision. Ann Surg 1985;202:659–63.
– Late surgery may be beneficial after
necrosis margins declared
Forks TP. Brown recluse spider bites. J Am Board Fam Pract 2000;13:415–23.

26. Dapsone
• Theoretically inhibits leukocyte
aggregation
Bryant SM, Pittman LM. Dapsone use in Loxosceles reclusa envenomation:
is there an indication? American Journal of Emergency Medicine
2003;21:89 - 90. King LE, Rees RS. Dapsone treatment of a brown
recluse bite. JAMA 1983;250:648.
• Reduces lesion size in guinea
pigs
Barrett SM, Romine-Jenkins M, Fisher DE. Dapsone or electric shock therapy
of brown recluse spider envenomation? Ann Emerg Med 1994;24:21-
5.
• No benefit in rabbits
Elston DM, Miller SD, Young III RJ, et al. Comparison of colchicine, dapsone,
triamcinolone, and diphenhydramine therapy for the treatment of
brown recluse spider envenomation: a double-blind, controlled study
in a rabbit model. Arch Dermatol 2005;141:595-7.
Phillips S, Kohn M, Baker D, et al. Therapy of brown spider envenomation: a
controlled trial of hyperbaric oxygen, dapsone, and cyproheptadine.
Ann Emerg Med 1995;25:363-8.
• No prospective trials with
benefits to humans
Swanson, DL., Vetter, RS. Loxoscelism. Clinics in Dermatology. 2006 May-
Jun;24(3):213-21.
• Side Effects
– Hemolysis in all patients
– Methemoglobinemia
– Headache
– GI upset
– Hepatitis
– Exfoliative dermatitis
– Agranulocytosis
– Motor neuropathy

27. Witnessed Recluse Bite?
Well Appearing
 UA
Ill Appearing
• Resuscitation
• CBC
• INR
• Fibrinogen
• BMP
• CK
Rosen JL, Dumitru JK, Langley EW, Meade Olivier CA. Emergency department death from systemic loxoscelism. Annals of Emergency Medicine. 2012 Oct;60(4):439-41.

28. Loxoscelism vs MRSA
Rogers, KM, Klotz, CR, Jack, M, Seger, D. Systemic Loxoscelism in the Age of Community Acquired Methicillin Resistant Staphylococcus aureus. Annals of Emergency
Medicine. 2011 Feb;57(2):138-40.

29. Systemic Loxoscelism Case
 3 yr old previously healthy girl
bitten by “fiddleback” while
removing old blankets
 2-3 hours- presented to rural ED,
discharged home after
evaluation
 6 hours- fever to 39.3ºC
 12 hours- N/V, malaise,
increased pain at bite, tea
colored urine
• 15 hours-presented to urban
children's ED
– WBC 20.7, Hbg 9.5, Plt 54
– INR 1.8
• 18 hours-transfused
• 19 hours- apneic, pulseless
– Massive transfusion (6u PRBCs, 1
FFP, 1 platelet)
– Undetectable hemoglobin
Rosen JL, Dumitru JK, Langley EW, Meade Olivier CA. Emergency department death from systemic loxoscelism. Annals of Emergency Medicine. 2012 Oct;60(4):439-41.

30. Chilean Recluse
• Loxosceles laeta
• Common to all of South America
• Los Angeles
• Winter Park, Florida
• Cambridge, Massachusetts
• Vancouver
• Treatment is same
• No more toxic than other native
recluses

31. http://ihdwallpapers.com/the_avengers_black_widow-wallpapers.html

32. Widow Spiders
• 30 species worldwide
• Females do not often
eat males
Vetter, RS, Isbister GK. Medical aspects of spider bites. Annual Review of Entomology. 2008;53:409-29.
• Dark or dry places
– Outdoor furniture
– Potted plants
– Storage boxes
– Outhouses

33. Widow Web
http://www.venombyte.com/venom/spiders/northern_black_widow.asp

34. Latrodectus spp
• Southern Black Widow- Latrodectus mactans
• Northern Black Widow- Latrodectus variolus
• Western Black Widow- Latrodectus hesperus
• Red Widow- Ladrodectus bishopi
• Brown Widow- Latrodectus geometricus

35. http://bugguide.net/node/view/1999/data
Widows

36. Southern Black
http://www.whatsthatbug.com/2010/07/17/black-widows/

37. http://bugguide.net/node/view/26336/data
Southern Black

38. http://www.pestid.msu.edu/InsectsArthropods/NorthernBlackWidowSpiderLatrodectusvariolus/tabid/263/Default.aspx
http://commons.wikimedia.org/wiki/File:Latrodectus_variolus_(Northern_Black_Widow),_F_Theridiidae.jpg
Northern Black

39. Northern Black
http://bugguide.net/node/view/26421/data

40. Western Black
http://nathistoc.bio.uci.edu/spiders/Latrodectus%20hesperus.htm

41. http://bugguide.net/node/view/26346/data
Western Black

42. Red
http://www.freshfromflorida.com/pi/enpp/ento/venomousspiders.html

43. Red
http://bugguide.net/node/view/26290/data

45. Brown
http://nathistoc.bio.uci.edu/spiders/Latrodectus%20geometricus.htm
http://cisr.ucr.edu/images/brown_widow_spider_large.jpg

46. http://bugguide.net/node/view/23403/data
Brown

47. Latrodectism
• Venom is α-Latrotoxin (α-LTX)
• Acetylcholine release at NMJ
• Pain
– Local, radiating, or regional
• Diaphoresis
– Local, radiating, or regional
• Hypertension
• Agitation
• Fever
• Muscle contraction
• Rhabdomyolysis
Monte AA, Bucher-Bartelson B, Heard KJ. A US perspective of symptomatic Latrodectus spp. envenomation and treatment: a National Poison Data System review. Ann
Pharmacother. 2011 Dec;45(12):1491-8.
Isbister GK, Fan HW. Spider bite. Lancet. 2011 Dec 10;378(9808):2039-47.

48. Treatments
Effective
• Analgesics
• Benzodiazepines
• Tetanus
• Antivenom
Less Effective
• Calcium
• Antibiotics
• Magnesium
Monte AA. Black widow spider (Latrodectus mactans) antivenom in clinical practice. Current Pharmaceutical Biotechnology. 2012 Aug;13(10):1935-9.
Clark R, Wethern-Kestner S, Vance M, Gerkin R. Clinical presentation and treatment of black widow spider envenomation: a review of 163 cases. Annals of Emergency
Medicine 1992;21:782-7.

49. Antivenom
• Antivenin (Latrodectus Mactans) • Analatro ®
Monte AA. Black widow spider (Latrodectus mactans) antivenom in clinical practice. Curr Pharm Biotechnol. 2012 Aug;13(10):1935-9.
Dart RC, Bogdan G, Heard K, Bartelson BB, Garcia-Ubbelohde W, Bush S, Arnold T, Clark RC, Hendey GW, Holstege C, Spradley EA. A Randomized, Double-Blind, Placebo-
Controlled Trial of a Highly Purified Equine F(ab)2 Antibody Black Widow Spider Antivenom. Ann Emerg Med. 2013 Feb 1.
Clark R, Wethern-Kestner S, Vance M, Gerkin R. Clinical presentation and treatment of black widow spider envenomation: a review of 163 cases. Ann Emerg Med
1992;21:782-7.

50. Don’t Do
• Calcium
– Old study
Key GF. 1981. A comparison of calcium gluconate and methocarbamol (Robaxin) in the treatment of
latrodectism (black widow spider envenomation). Am. J. Trop. Med. Hyg.30:273–77
– 96% with no relief
Clark R, Wethern-Kestner S, Vance M, Gerkin R. Clinical presentation and treatment of black widow
spider envenomation: a review of 163 cases. Ann Emerg Med 1992;21:782-7.
• Magnesium
– Old study
Cesareo DA. 1934. “Red back” spider bite and magnesium sulphate treatment. Am. J. Trop. Med.
Hyg. 14:33–44
• Antibiotics
– No benefit, harmful side effects

51. Conclusions
• Consider envenomation in
endemic areas
• Treat supportively

52. Questions?