What is the management of spider bites?

Management of Spider Bites

Emergency medical services should be called immediately if a person bitten by a spider develops systemic symptoms such as difficulty breathing, muscle rigidity, dizziness, or confusion. 1

Initial Assessment and Triage

When evaluating a suspected spider bite, follow this approach:

1. Assess for systemic symptoms requiring emergency care:

   • Difficulty breathing or respiratory distress
   • Muscle rigidity or cramping
   • Dizziness or confusion
   • Signs of shock
   • Severe pain uncontrolled by over-the-counter medications 1

2. Identify the spider if possible:

   • Black widow (Latrodectus) - round black body with red hourglass marking
   • Brown recluse (Loxosceles) - violin-shaped marking on cephalothorax
   • Other species with regional importance 1

Management Based on Spider Type

Black Widow Spider Bites (Latrodectus)

• Clinical presentation: Severe crampy pain, muscle rigidity, diaphoresis, hypertension; minimal local tissue injury 1
• Management:
  • Pain control with acetaminophen or NSAIDs
  • Consider muscle relaxants
  • Seek medical care for severe pain or systemic symptoms
  • Specific antivenin available in medical settings for severe cases 2

Brown Recluse Spider Bites (Loxosceles)

• Clinical presentation: Painful ulcerated wounds that progress over days to weeks; potential for hemolysis and rhabdomyolysis 1
• Management:
  • Rest and elevate the affected area
  • Apply ice compresses to reduce pain and swelling
  • Wound care and antibiotics if secondary infection develops
  • Seek medical care if an open wound develops or pain is severe 1, 2
  • Early medical intervention (within 24 hours) is associated with better outcomes than delayed treatment 3

Other Spider Bites

• Most cause only mild local reactions requiring minimal treatment
• Apply ice for pain relief
• Use over-the-counter pain medications as needed 1

Symptomatic Treatment

For local reactions:

• Cold compresses to reduce pain and swelling 1
• Over-the-counter pain medications:
  • Acetaminophen and NSAIDs can alleviate local pain 1
• Topical lidocaine (if skin is intact) can provide pain relief 1
• Oral antihistamines may help reduce itching associated with local reactions 1

When to Seek Medical Care

Advise patients to seek medical care if:

• Pain extends beyond the bite site
• Pain becomes severe and is not controlled by over-the-counter medications
• An open wound develops
• Systemic symptoms develop (anywhere in the body) 1

Common Pitfalls and Caveats

1. Misdiagnosis: Many lesions attributed to spider bites are actually caused by other conditions. True spider bites are relatively uncommon as most spiders cannot pierce human skin 4.

2. Unnecessary antibiotic use: Antibiotics are not indicated unless there is evidence of secondary infection. Swelling and redness are often due to mediator release, not infection 1.

3. Delayed treatment: For brown recluse bites, there is a significant relationship between time to treatment and severity of lesions. Earlier treatment (within 24 hours) is associated with better outcomes 3.

4. Overestimation of danger: While spider bites can cause concern, most species in North America cause minimal medical problems requiring little treatment 5.

5. Failure to recognize severe systemic reactions: Although rare, some spider bites can cause severe systemic reactions including facial nerve palsy and septic shock, requiring immediate medical attention 6.