How does one treat Loxoscelism?
June 28,2024
Brown Recluse Spiders (Loxosceles reclusa) are endemic to the state of Tenn. These spiders are also called "violin" or fiddleback" spiders due to the violin-shaped marking on the spider's back. They tend to be “reclusive” and like to hide-particularly in cardboard boxes or woodpiles. They are more likely to be indoor or barn spiders rather than the ones found in the grass.
Cutaneous loxoscelism: Brown recluse spider bites (BRSB) are often unnoticed. Dermatonecrosis may appear within 24 hours or be delayed for days. Typically, the bite site initially itches, tingles, and swells. It becomes painful and develops a purplish lesion, surrounded by gray/white, ischemic looking tissue, further surrounded by an erythematous rim (“red, white, and blue”). A blister or bleb (clear or hemorrhagic) may develop at the bite site. Necrotic tissue is located beneath these blebs. Pain worsens as inflammation and ischemia spread. Necrosis occurs and eschar may form days to weeks after envenomation. Areas of the body that have more fatty tissue is most subject to severe necrosis.
Treatment: DO NOTHING. This is extremely difficult for physicians. Following a shower or bath, pat the area dry. No creams, ointments (AVOID neosporin) or steroids. Gently placing Ice on the wound alleviates pain better than any pain meds. Most physicians place the patient on antibiotics due to concern about cellulitis. The rapidly spreading erythema is usually due to the toxin. (If cellulitis were spreading that quickly, the patient should be clinically ill, which they are not.) Most spider bites do extremely well, with little intervention. Even after the eschar falls off, the wound heals from the bottom. Dapsone hasn't been shown to reduce the amount of venom effects on the tissue. The side-effect of Dapsone can be drug-induced hemolytic anemia which could potentially create a life threat to a self-limiting illness.
Systemic loxoscelism (viscerocutaneous loxoscelism): Systemic toxicity usually develop within 2-4 days of the bite and can be life-threatening. Signs and symptoms include rash, fever, chills, malaise, weakness, nausea, vomiting, abdominal discomfort, arthralgias. The life-threat is hemolytic anemia which may be progressive enough to cause death, especially in children. Intravascular hemolysis may result in hemoglobinuria-so any patient with this finding is likely having active hemolysis and may be at risk for massive hemolysis. Extravascular hemolysis may also occur with BRSB. Extravascular hemolysis does not result in the hemoglobinuria so serial hematocrits are the only way to follow the degree of hemolysis Transfusion may be required and the active hemolysis can persist for days. Admission should be considered in ill-appearing patients with systemic illness. There have been deaths secondary to rapid hemolysis in children in TN.
Call the Poison Center for help with managing BRSB. Patients may also be referred to Toxicology Clinic to see a medical toxicologist for help with management.
Question prepared by Donna Seger MD
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Donna Seger MD Professor Emerita
Dept of Medicine
VUMC
Question of the Week has been distributed since 2001 and currently has a distribution of 3000 Health Care Providers. The QoW is short, to the point, and addresses many toxicological issues such as overdose management, pharmaceuticals, envenomations, new substances/outbreaks, environmental exposures etc. (Find previous QoW at Tennessee Poison Center (TPC) website) . Donna Seger MD created the QoW for stakeholders and interested health care providers as an email correspondence tool about the latest information on toxins and toxicants. She has been pivotal in directing the QoW for the past 23 years. Starting this academic year, Rebecca Bruccoleri MD, Medical Director, TPC and Saralyn Williams MD, two of our Toxicologists, will be providing oversight for this service.
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Rebecca Bruccoleri, MD Saralyn Williams, MD Donna Seger, MD