Skin nontumor
Infestations
Brown recluse spider
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PubMed Search: Brown recluse spider[title]
Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Etiology | Clinical features | Diagnosis | Case reports | Treatment | Clinical images | Microscopic (histologic) description | Differential diagnosis | Board review style question #1 | Board review style answer #1Cite this page: Nagarajan P, Suo L. Brown recluse spider. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skinnontumorbrownreclusespider.html. Accessed March 24th, 2023.
Definition / general
- One of the two venomous spiders in the North America (CDC website - Venomous Spiders); also black widow spider
- Bite and venom can cause extensive necrosis, hemorrhage, blistering and ulceration (Semin Cutan Med Surg 2014;33:123)
Essential features
- Bite and venom can cause extensive necrosis, hemorrhage, blistering and ulceration
- Misdiagnosis of methicillin resistant Staphylococcus aureus (MRSA) as spider bites has been reported and may have fatal consequences
- No standard treatment to date
- Usually associated with eosinophils but other histologic features vary: neutrophilic vasculitis with hemorrhage, arterial wall necrosis or eschar covered ulceration and subcutaneous necrosis
Terminology
- Also called loxoscelism (Loxosceles reclusa), necrotizing arachnidism
Epidemiology
- Mainly populates the southern central states and some South American countries
- In 2011, 1487 Loxosceles bites were reported in the US, mainly in Southeastern states (Clin Toxicol (Phila) 2012;50:911)
Sites
- Any body site can be affected, especially exposed skin
- Cutaneous manifestations occur in around 80% cases around the site of bite, predominantly in the lower limbs (Rev Inst Med Trop Sao Paulo 1989;31:403)
Etiology
- Bite induced injury
- Hemotoxic and proinflammatory venom
Clinical features
- Initial symptoms include burning stinging, pain, erythema and edema
- Local envenomation associated skin lesions: extensive necrosis, hemorrhage, blistering and ulceration (Semin Cutan Med Surg 2014;33:123)
- May take 2 months to heal (N Engl J Med 2013;369:e6)
- Secondary bacterial infections and osteomyelitis have also been reported (Eplasty 2008;8:e45)
- A chronic pyoderma gangrenosum-like reaction has also been reported (South Med J 1990;83:243)
- Systemic loxoscelism is a rare complication after envenomation (J Clin Immunol 2014;34:544)
- Symptoms include severe hemolysis, acute kidney injury, secondary hemophagocytic lymphohistiocytosis
Diagnosis
- Misdiagnosis may have fatal consequences, especially misdiagnosis of methicillin resistant Staphylococcus aureus (MRSA) as spider bites (N Engl J Med 2006;355:666)
- NOT RECLUSE: a mnemonic to avoid misdiagnoses (JAMA Dermatol 2017;153:377)
- Diagnosis can be made by swabbing the lesion and using a specific enzyme linked immunosorbent assay (ELISA) to detect the venom
Case reports
- 6 year old boy with massive hemolysis, shock and acute renal failure after loxosceles envenomation (Pediatrics 2014;134:e1464)
- 10 year old boy developed necrotic rash, secondary hemophagocytic lymphohistiocytosis from a brown recluse spider bite (J Clin Immunol 2014;34:544)
- 22 year old woman with severe haemolytic anaemia with erythrophagocytosis following the bite of a brown recluse spider (Br J Haematol 2014;167:1)
- 23 year old man developed dermonecrosis and acute kidney injury following the bite of brown recluse spider (Indian J Nephrol 2014;24:246)
- 60 year old woman with a necrotic lesion of the left breast (JAAPA 2014;27:32)
- 63 year old woman with bilaterally decreased vision after a bite from a brown recluse spider (Cutan Ocul Toxicol 2016;35:168)
Treatment
- No standard treatment to date
- First aid treatment: wash the bite area with soap and water; apply a cold pad to reduce inflammation; seek professional medical treatment (CDC website - Venomous Spiders)
- Topical treatment: pain control, anti inflammatory medications; topical antibiotics for secondary bacterial infections; hyperbaric oxygen therapy for nonhealing wounds (Adv Skin Wound Care 2016;29:560)
- Surgical interventions including debridement of the envenomation site and possibly skin grafting (J Foot Ankle Surg 2014;53:320)
- Therapeutic plasma exchange for severe systemic loxoscelism associated hemolysis and acute kidney failure (J Med Toxicol 2015;11:364)
Clinical images
Images hosted on other servers:
Brown recluse
Dorsal view of the brown recluse spider
Necrotic rash from
a brown recluse
spider bite
Brown recluse spider bites
Microscopic (histologic) description
- Varies from neutrophilic vasculitis with hemorrhage to arterial wall necrosis to eschar covered ulceration and subcutaneous necrosis
- Usually eosinophils in the inflammatory infiltrate
Differential diagnosis
- Bites from other insects
- Diabetic neuropathy (J Foot Ankle Surg 2014;53:320)
- Other infections: bacteria (MRSA), viral, fungal, syphilis
- Squamous cell carcinoma
Board review style question #1
- Which description of brown recluse spider bites is FALSE:
- Cutaneous manifestations occur in around 80% cases around the site of bite, predominantly in the lower limbs
- The gold standard for treatment is antibiotics and debridement
- Microscopic features vary from neutrophilic vasculitis with hemorrhage to arterial wall necrosis to eschar covered ulceration and subcutaneous necrosis
- Misdiagnosis of methicillin resistant Staphylococcus aureus (MRSA) as spider bites may have fatal consequences
- Loxosceles reclusa, the brown recluse spider, is one of two medically significant venomous spiders in the North America.
Board review style answer #1
B. There is no standard treatment for a bite from a brown recluse spider.
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