What is the therapy for spider bites?

Therapy for Spider Bites

The most effective therapy for spider bites depends on the specific spider species, with black widow and brown recluse spider bites requiring different treatment approaches based on their distinct venom effects. 1, 2

Initial Assessment and First Aid

• Thoroughly irrigate the bite wound with copious amounts of clean water to reduce venom load and prevent infection 2
• Remove rings and other constricting objects from the bitten extremity as swelling may occur 2
• Apply ice to the bite site for local pain relief (place a thin barrier between ice and skin to prevent tissue damage) 1, 2
• Use over-the-counter acetaminophen and NSAIDs for pain management 1, 2
• Do not apply suction to the bite site as this is ineffective and potentially harmful 2
• Do not apply tourniquets or pressure immobilization bandages as these may worsen tissue injury 2

Black Widow Spider Bites

• Black widow bites typically cause severe crampy pain, muscle rigidity, diaphoresis, and hypertension with minimal local tissue injury 1
• First-line treatment includes localized wound care and over-the-counter analgesics for pain 1
• For more severe symptoms, treatment options include:
  • Calcium gluconate for muscle cramping 3, 4
  • Muscle relaxants such as methocarbamol 3
  • Benzodiazepines like diazepam for severe muscle spasms 3
  • Specific antivenin for severe cases, though pain control and muscle relaxants are generally adequate 5, 3

Brown Recluse Spider Bites

• Brown recluse bites can cause dermonecrosis within 72-96 hours 5
• Treatment approach includes:
  • Rest, ice compresses, and antibiotics to prevent secondary infection 5
  • Dapsone has shown effectiveness in controlling necrotic lesions 5, 4
  • Delay surgical intervention for several weeks to allow demarcation of necrotic tissue 5
  • Systemic corticosteroids may be helpful for systemic loxoscelism with hemolysis 5, 6
  • For non-healing wounds (2-3 months after bite), hyperbaric oxygen therapy can be effective 7

When to Seek Medical Care

• Seek immediate medical attention if:
  • Pain extends beyond the bite site or becomes severe 1, 2
  • Pain is not controlled by over-the-counter medications 1
  • Systemic symptoms develop (difficulty breathing, muscle rigidity, dizziness, confusion) 1, 2
  • Signs of infection appear (progressive erythema, purulent discharge, fever) 8

Special Considerations

• Very young, very old, and those with underlying health conditions are at higher risk for severe reactions 1
• Avoid assuming antibiotics are needed for swelling around the bite site, as swelling is typically caused by mediator release, not infection 8
• Universal prophylaxis with antibiotics is not recommended for bite wounds in general 8

Common Pitfalls

• Delaying medical care when systemic symptoms are present 1
• Underestimating the severity of envenomation based solely on local findings at the bite site 1
• Applying suction, tourniquets, or pressure immobilization bandages 2
• Performing early surgical intervention for brown recluse bites before tissue demarcation 5