What are the symptoms and treatment of a brown recluse (Loxosceles reclusa) spider bite?

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Last updated: April 29, 2025View editorial policy

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From the Guidelines

If you suspect a brown recluse bite, seek medical attention immediately, as these bites can cause painful ulcerated wounds that progress over days to weeks, sometimes associated with hemolysis and rhabdomyolysis, as stated in the 2024 American Heart Association and American Red Cross guidelines for first aid 1. While waiting for medical care, it is recommended to clean the area with soap and water, apply a cold compress to reduce pain and swelling, elevate the affected limb, and take acetaminophen or ibuprofen for pain relief, as suggested by the guidelines 1. Some key points to consider when dealing with a brown recluse bite include:

  • Cleaning the area with soap and water to prevent infection
  • Applying a cold compress to reduce pain and swelling
  • Elevating the affected limb to reduce swelling
  • Taking acetaminophen or ibuprofen for pain relief, as recommended by the guidelines 1
  • Not applying heat, which can accelerate tissue damage It is essential to note that brown recluse bites can cause necrotic skin lesions due to their cytotoxic venom, and most bites heal without serious complications, but some can develop into severe wounds requiring antibiotics, wound care, or even surgery, as mentioned in the guidelines 1. People should prevent encounters by sealing cracks in homes, reducing clutter, shaking out clothing and shoes before use, and wearing gloves when handling stored items in areas where these spiders may hide. According to the guidelines, emergency services should be called if a person bitten by a spider or stung by a scorpion develops symptoms throughout the body such as difficulty breathing, muscle rigidity, dizziness, or confusion, and a person bitten by a spider or stung by a scorpion should seek medical care if pain extends beyond the site of the bite/sting, becomes severe, and is not controlled by over-the-counter pain medications; if an open wound develops; or if the person experiences symptoms throughout the body 1.

From the Research

Brown Recluse Spider Bites

  • Brown recluse spider bites can cause necrotic ulcerations of various sizes and dimensions 2
  • The current standard of care for brown spider bites includes analgesics, ice, compression, elevation, antihistamines, and surgical debridement 2
  • Hyperbaric oxygen therapy (HBOT) has been used in the treatment of brown spider bites, particularly in the late, chronic, nonhealing stage 2, 3

Treatment Options

  • Topical nitroglycerine patches and vitamin C tablets have been provided as treatment options, but their effectiveness is unclear 4
  • Systemic corticosteroids and dapsone have been associated with slower healing and increased probability of scarring 4
  • HBOT has been shown to be effective in healing nonhealing wounds caused by brown spider bites, even months after the bite 2
  • Dapsone and hyperbaric oxygen therapy have been used together to bring the adverse response to the bite under control 3

Diagnosis and Challenges

  • The actual spider bite often goes unnoticed for several hours, making diagnosis and treatment difficult 3
  • There is no commercially available assay to provide a definitive diagnosis for the brown recluse spider bite, and antivenom is scarce 3
  • Capture of the offending spider appears to be most helpful in the diagnosis and proper treatment of spider bites 3

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Management of brown recluse spider bites in primary care.

The Journal of the American Board of Family Practice, 2004

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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