What is the treatment for a spider bite with necrosis?

Treatment for Spider Bites with Necrosis

The treatment for spider bites with necrosis should include thorough wound irrigation, local wound care, pain management, and consideration of hyperbaric oxygen therapy for non-healing necrotic wounds, especially those caused by brown recluse spiders. 1, 2

Initial Management

• Thoroughly irrigate the bite wound with a large volume of warm or room temperature potable water until there is no foreign matter in the wound 1
• Apply antibiotic ointment and cover with a clean occlusive dressing to improve healing and reduce infection risk 1
• Remove rings and other constricting objects from the bitten extremity, as swelling may occur 1
• Apply ice with a clean barrier between ice and skin for pain relief 1

Pain Management

• Over-the-counter acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended for local pain relief 1, 3
• If the skin is intact, topical lidocaine can be applied for pain relief 1, 3
• Oral analgesics may be needed for several days as pain persists 1

Wound Care for Necrotic Lesions

• For established necrotic wounds, local wound care with appropriate dressings is essential 2, 4
• Sodium hypochlorite solution packs, equine catalase gel, and polyhexamethylene biguanide cream have been used successfully in treating necrotic ulcers from Loxosceles spider bites 4
• Surgical debridement may be necessary for extensive necrotic tissue 2, 5
• Full-thickness skin grafts may be required for reconstruction of facial defects after necrotic spider bites 6

Advanced Treatment Options

• Hyperbaric oxygen therapy (HBOT) should be considered for non-healing necrotic wounds caused by brown spider bites, even months after the initial bite 2
• HBOT at 2 ATA (atmospheres absolute) with 100% oxygen has shown success in treating chronic non-healing wounds from brown spider bites 2
• Dapsone has been used in some cases to control adverse responses to brown recluse spider bites 7

Antibiotic Management

• Antibiotics are not routinely recommended for spider bites unless signs of infection are present 8
• Signs of infection requiring antibiotic treatment include:
  • Progressive erythema extending beyond the initial bite site 8
  • Purulent discharge from the wound 8
  • Systemic signs of infection such as fever or elevated white blood cell count 8
• For bacterial superinfections, intravenous piperacillin/tazobactam or intramuscular ceftriaxone may be used 4

When to Seek Medical Care

• Medical attention should be sought if:
  • Pain extends beyond the bite site or becomes severe 1, 3
  • Pain is not controlled by over-the-counter medications 1, 3
  • An open wound develops 1, 3
  • Signs of infection appear 1
  • Systemic symptoms develop (difficulty breathing, muscle rigidity, dizziness, confusion) 1, 3

Common Pitfalls to Avoid

• Do not apply suction to the bite site as this is ineffective and potentially harmful 1
• Do not apply tourniquets or pressure immobilization bandages as these may worsen tissue injury 1
• Do not assume antibiotics are needed for swelling around the bite site, as swelling is typically caused by mediator release, not infection 8, 1
• Do not delay medical care when systemic symptoms are present 3
• Do not underestimate the severity of envenomation based solely on local findings at the bite site 3

Recovery Expectations

• Most patients with local symptoms only will recover completely within 24-48 hours 1
• Necrotic wounds from brown recluse spider bites may take several weeks to heal 4
• Scarring is common after necrotic spider bites, occurring in most patients 4