Emergency Department Care
Treatment of brown recluse envenomation is directed by the severity of the injury. General wound management consists of local debridement, elevation, and loose immobilization of the affected area.
Because the activity of sphingomyelinase D is temperature dependent, application of local cool compresses is helpful and should be continued until progression of the necrotic process appears to have stopped.
Dapsone, because of its leukocyte inhibiting properties, frequently has been recommended by authorities to treat local lesions. However, because of the potential for adverse effects associated with dapsone use, especially in the setting of G-6-PD deficiency, appropriate caution should be exercised if using this medication. [11] To date, no well-controlled studies have shown dapsone to affect clinical outcome in human brown recluse envenomations; therefore, it is not routinely recommended. [12, 13]
Other treatments such as colchicine, steroids, antivenom, nitroglycerin patches, and surgical excision have been reported, but insufficient data exist to support their clinical use today. [14, 15]
Some evidence indicates that hyperbaric oxygen therapy is beneficial in an animal model for reducing skin lesion size, but controlled human studies of this technique have not been performed. [12, 16, 17]
Patients exhibiting signs of systemic toxicity should be admitted and evaluated for evidence of coagulopathy, hemolysis, hemoglobinuria, renal failure, or further progression of systemic illness.
Urinalysis can provide early evidence of systemic involvement (eg, hemoglobinuria, myoglobinuria) and can be performed easily at the bedside in all patients.
Inpatient care
Admit patients to the hospital for observation if they have rapidly expanding lesions or show evidence of systemic toxicity.
Patients with rapidly expanding lesions require good conservative wound care, including splinting and elevation. Appropriately treat any bacterial superinfection that occurs.
Carefully manage fluid and electrolytes in patients with evidence of systemic loxoscelism. Monitor patients' renal status and provide blood transfusions as needed. A short course of oral prednisone may reduce hemolysis. These patients may be discharged when their renal and hematologic statuses are stable.
Consultations
Consult a plastic surgeon or other specialist with experience in wound management in patients who might require delayed skin grafting or have a prolonged recovery period.
The images below show the progression of a brown recluse spider bite wound, which needed a skin graft for healing.
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 multiple doses of intravenous antibiotics and pain medication. 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.
Prevention
Persons living in endemic areas should wear protective clothing and remain attentive when venturing into habitats of the brown recluse spider.
Cobwebs and spiders should be carefully removed from under and behind beds. One should use caution when putting on clothing that has been kept in storage and not worn for some time.
Long-Term Monitoring
Before discharging patients from the hospital, instruct them on proper wound care techniques and in proper cooling of the lesion for the first 72 hours. Schedule patients for daily wound checks until the lesion is stable or improving.
At each follow-up visit for the first 72 hours, perform a urine bedside test for blood and a CBC count with platelet count to assess for any evidence of systemic toxicity.
Inform patients that the development of fever or dark urine necessitates immediate return to the ED or a call to their primary physician.
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Classic finding of a vesicle with surrounding erythema at 24 hours following brown recluse envenomation. Photo by Thomas Arnold, MD.
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Illustration of a brown recluse spider with the fiddle displayed prominently on its dorsum.
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Spider envenomations, brown recluse. Envenomation site on inner thigh untreated at 1 week. Photo by Thomas Arnold, MD.
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Typical appearance of a male brown recluse spider. Photo contributed by Michael Cardwell, Victorville, Calif.
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Female brown recluse with size scale. Photo contributed by Michael Cardwell, Victorville, Calif.
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Spider envenomations, brown recluse. Close-up image of dorsal violin-shaped pattern. Photo contributed by Michael Cardwell, Victorville, Calif.
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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.
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Spider bite, brown recluse. The third day after the bite. The skin continues to die. Courtesy of Dale Losher.
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Spider bite, brown recluse. Another view of the wound 3 days after the bite. Courtesy of Dale Losher.
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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 multiple doses of intravenous antibiotics and pain medication. Courtesy of Dale Losher.
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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.
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Spider bite, brown recluse. Waiting to see skin graft results 38 days after the bite. Courtesy of Dale Losher.
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Spider bite, brown recluse. Skin graft results 38 days after the bite. Courtesy of Dale Losher.
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Spider bite, brown recluse. View of healed wound approximately 10 months after bite. Courtesy of Dale Losher.
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Dermonecrotic arachnidism represents a local cutaneous injury with tissue loss and necrosis.
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Brown recluse spider. Courtesy of US Centers for Disease Control and Prevention.
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Brown recluse spider. Courtesy of US Centers for Disease Control and Prevention.
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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).
