What is the treatment for a spider bite?

Spider Bite Treatment

The treatment for spider bites includes local wound care with soap and water, pain management with over-the-counter medications, and seeking emergency medical care for systemic symptoms or severe local reactions. 1

Initial Assessment and Identification

• Most spider bites in the United States are benign with only self-limited local symptoms
• Medically significant spider bites in the US primarily come from:
  • Black widow spiders (genus Latrodectus) - cause severe crampy pain, muscle rigidity, diaphoresis, and hypertension
  • Brown recluse spiders (genus Loxosceles) - cause painful ulcerated wounds that progress over days to weeks, sometimes with hemolysis and rhabdomyolysis 1
• True spider bites are rare and frequently misdiagnosed; many presumed spider bites are actually skin infections or other conditions 2

Treatment Algorithm

Immediate First Aid

1. Clean the wound

   • Wash the bite area thoroughly with soap and water to prevent secondary infection 3

2. Pain management

   • Use over-the-counter acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief (Class 2a recommendation) 1
   • Apply ice for local pain relief (Class 2a recommendation) 1
   • If skin is intact, topical lidocaine may help relieve local pain (Class 2a recommendation) 1

3. Reduce swelling

   • Apply ice or cold compresses for 10-15 minutes several times daily 3

When to Seek Medical Care

Call emergency services immediately if the person develops:

• Difficulty breathing
• Muscle rigidity
• Dizziness
• Confusion 1

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 appear 1

Medical Treatment Based on Spider Type

Black Widow Spider Bites

• Focus on pain control and muscle relaxants
• Calcium gluconate may be helpful
• Specific antivenin is available for severe cases 4

Brown Recluse Spider Bites

• Rest and ice compresses
• Antibiotics to prevent secondary infection
• Dapsone may be considered (though controversial)
• Delay surgical intervention for several weeks 4
• Systemic corticosteroids may help for systemic loxoscelism with hemolysis 4

Special Considerations

Infection Risk

• Monitor for signs of secondary infection, which is a common complication
• If infection develops, consider antibiotic treatment
• Be aware that methicillin-resistant Staphylococcus aureus (MRSA) has been frequently isolated from infected "spider bite" wounds 5
• Infected wounds should not be closed and may require debridement 3

Common Pitfalls

1. Misdiagnosis

   • Many lesions attributed to spider bites are actually caused by other conditions 6, 2
   • True spider bites can only be definitively diagnosed when the spider is seen at the time of the bite and identified by an expert 2
   • Misdiagnosis can lead to delays in appropriate care and potentially adverse outcomes 2

2. Delayed Treatment

   • Delaying treatment for severe systemic symptoms can lead to serious complications
   • Early recognition of medically significant envenomation is crucial 1

3. Unnecessary Antibiotics

   • Not all spider bites require antibiotics; reserve for signs of secondary infection 3

4. Inappropriate Surgical Intervention

   • Early surgical intervention for brown recluse bites may worsen outcomes; surgery should typically be delayed 4

Remember that most spider bites heal without specific intervention, and the primary goals of treatment are pain management, preventing infection, and recognizing when more advanced care is needed.