Treatment for Spider Bites
For most spider bites, treatment consists of thorough wound irrigation with water, ice application for pain relief, over-the-counter analgesics, antibiotic ointment with occlusive dressing, and elevation of the affected area—antibiotics are NOT routinely indicated unless clear signs of secondary bacterial infection develop. 1, 2
Immediate First Aid
- Irrigate the wound thoroughly with copious amounts of warm or room temperature potable water until all foreign matter is removed 1, 2
- Apply ice with a clean barrier between ice and skin for local pain relief 1, 2
- Remove rings and constricting objects immediately from the affected extremity, as swelling may occur 1, 2
- Apply antibiotic ointment and cover with a clean occlusive dressing to improve healing and reduce infection risk 1, 2
- Elevate the affected extremity to accelerate healing and reduce swelling 2
Pain Management
- Over-the-counter acetaminophen or NSAIDs are recommended for pain control 2
- Topical lidocaine 5% can be applied if the skin is intact for additional pain relief 2
- Oral antihistamines can reduce itching and swelling 2
Critical Pitfall: When Antibiotics Are NOT Needed
Large swelling occurring in the first 24-48 hours is caused by allergic inflammation and mediator release, NOT infection—do not prescribe antibiotics prophylactically. 1, 2 Universal prophylaxis with antibiotics is not recommended for bite wounds 2
When to Seek Immediate Medical Care
Seek emergency care if any of these develop:
- Systemic symptoms: difficulty breathing, bronchospasm, laryngospasm, muscle rigidity, dizziness, confusion, syncope, or hypotension 1, 2
- Rapidly progressive swelling involving the face, lips, tongue, or throat suggesting angioedema 2
- Severe pain extending beyond the bite site or uncontrolled by over-the-counter medications 1, 2
- Signs of secondary bacterial infection: progressive erythema extending beyond initial site, purulent discharge, fever, or elevated white blood cell count 2
When Antibiotics ARE Indicated
Only prescribe antibiotics if clear signs of secondary bacterial infection develop (not for initial swelling):
- First-line oral therapy: trimethoprim-sulfamethoxazole or doxycycline to cover MRSA 2
- Alternative option: clindamycin, if local resistance patterns permit 2
Special Considerations for Venomous Spiders
Brown Recluse Spider Bites
- Produce painful ulcerated wounds that progress over days to weeks, sometimes with hemolysis and rhabdomyolysis 2, 3, 4
- Primary treatment: rest, ice compresses, and delayed surgical debridement (several weeks, not immediate) 2, 3
- Dermonecrosis typically develops within 72-96 hours 3
Black Widow Spider Bites
- Produce muscle spasms and rigidity starting at the bite site within 30 minutes to 2 hours, with minimal skin changes 4
- Treatment focuses on pain control, muscle relaxants, and calcium gluconate 3, 5
- Antivenin is available but reserved for severe reactions 5
What NOT to Do
- Do not apply suction to the bite site—it is ineffective and potentially harmful 1, 2
- Do not apply tourniquets or pressure immobilization bandages—they may worsen tissue injury 1, 2
- Do not assume antibiotics are needed for swelling around the bite site 1
- Do not close infected wounds 2