What is the treatment for spider bites?

Spider Bite Treatment

The treatment of spider bites should focus on wound care, pain management, and monitoring for complications, with most bites requiring only cleaning with soap and water, cold compresses, elevation of the affected area, and over-the-counter pain medications. 1

Initial Assessment and Management

General Spider Bites

1. Clean the wound:

   • Wash thoroughly with soap and water 1
   • Remove any superficial debris 2

2. Reduce inflammation:

   • Apply cold compresses for 10-15 minutes several times daily 1
   • Elevate the affected extremity if significant edema is present 1

3. Pain management:

   • Use over-the-counter acetaminophen or NSAIDs 1
   • For intact skin, topical lidocaine (4-5%) can help with pain relief 1

4. Itch relief:

   • Oral antihistamines for pruritus 1
   • Topical hydrocortisone (0.5-1%) for local inflammation 1
   • Calamine lotion can be applied to affected areas as needed for comfort 3

Management Based on Spider Type

Brown Recluse Spider Bites

These bites can cause dermonecrosis within 72-96 hours 4

1. Local care:

   • Rest and ice compresses 4
   • Antibiotics to prevent secondary infection 4, 5
   • Avoid early surgical intervention - delay surgery for several weeks if needed 4

2. Medication considerations:

   • Evidence regarding dapsone is mixed - while historically recommended 4, 6, more recent research shows it may increase scarring and delay healing 7
   • Systemic corticosteroids may be helpful for systemic loxoscelism with hemolysis 4, but have been associated with slower healing in local wounds 7

Black Widow Spider Bites

These produce minimal skin changes but can cause muscle cramping and neuromuscular symptoms 4

1. Treatment options:
   • Pain control with analgesics 4
   • Muscle relaxants may help with cramping 4, 6
   • Calcium gluconate for symptom control 4, 6
   • Specific antivenin available but generally reserved for severe cases 4

Monitoring for Complications

Signs requiring immediate medical attention:

• Difficulty breathing, muscle rigidity, dizziness, or confusion 1
• Pain extending beyond the bite site or becoming severe 1
• Development of an open wound 1
• Systemic symptoms: fever, rash, muscle pain, hemolysis 1
• Signs of infection: increasing erythema after 48-72 hours, disproportionate pain, purulent discharge 1

Infection management:

• Most spider bites (80-90%) do not require antibiotics 1
• If infection develops, antibiotics active against streptococci and staphylococci for 5 days:
  • Cephalexin 500 mg four times daily 1
  • Clindamycin 300-450 mg three times daily (for penicillin-allergic patients) 1
  • Amoxicillin/clavulanic acid 875/125 mg twice daily 1

Follow-up and Referral

• Re-evaluate in 48-72 hours if no improvement 1
• Consider hospitalization for:
  • Suspected deep necrotizing infection
  • Systemic signs of infection
  • Systemic loxoscelism with hemolysis
  • Failure of outpatient treatment 1

Important Caveats

• Avoid early surgical debridement of spider bites as this may enlarge the wound and impair healing 2, 4
• Research shows that commonly used treatments (corticosteroids, dapsone) may actually delay healing and increase scarring in brown recluse bites 7
• The median healing time for spider bites is approximately 17 days, with only about 21% resulting in permanent scarring 7
• Predictors of slower healing include higher severity, more necrosis at presentation, older age, diabetes, and delayed medical attention 7