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
Initial Wound Care and First Aid
- Immediately irrigate the bite wound thoroughly with copious amounts of warm or room temperature potable water until all foreign matter is removed. 1, 2
- Apply antibiotic ointment and cover with a clean occlusive dressing to improve healing and reduce infection risk. 1, 2
- Remove rings and any constricting objects from the affected extremity immediately, as swelling may occur. 1, 2
- Elevate the affected area to accelerate healing and reduce swelling. 2
Pain Management
- Apply ice to the bite site with a clean barrier between ice and skin for local pain relief. 1, 2
- Use over-the-counter acetaminophen or NSAIDs for pain control. 1, 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 Actually Needed
Swelling in the first 24-48 hours is caused by allergic inflammation and mediator release, NOT infection—do not assume antibiotics are needed. 1, 2
- Universal prophylactic antibiotics are NOT recommended for bite wounds. 2
- Antibiotics are only indicated when clear signs of secondary bacterial infection appear:
- When secondary bacterial infection is confirmed, first-line oral therapy includes trimethoprim-sulfamethoxazole or doxycycline to cover MRSA. 2
- Alternative options include clindamycin if local resistance patterns permit. 2
When to Seek Immediate Medical Care
Seek emergency medical attention if any of the following develop:
- Systemic symptoms including difficulty breathing, bronchospasm, laryngospasm, muscle rigidity, dizziness, confusion, syncope, or hypotension—these indicate anaphylaxis requiring immediate epinephrine. 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
- An open wound develops or signs of infection appear. 1
Special Considerations for Venomous Spider Bites
Brown Recluse Spider (Loxosceles species)
- Brown recluse bites can cause painful ulcerated wounds that progress over days to weeks, sometimes associated with hemolysis and rhabdomyolysis. 2, 3
- Primary treatment remains rest, ice compresses, and delayed surgical debridement (several weeks after the bite). 2, 4, 5
- Dermonecrosis typically develops within 72-96 hours. 4
- Dapsone has been used historically for brown recluse bites, though evidence is limited. 4, 5
Black Widow Spider (Latrodectus species)
- Black widow bites produce minimal skin changes but cause muscle cramping, pain, and neuromuscular symptoms starting 30 minutes to 2 hours after the bite. 4, 3
- Treatment focuses on pain control, muscle relaxants, and calcium gluconate. 4, 5
- Specific antivenin is available but reserved for severe reactions. 4, 5
What NOT to Do
- Do not apply suction to the bite site—this is ineffective and potentially harmful. 1, 2
- Do not apply tourniquets or pressure immobilization bandages, as these may worsen tissue injury. 1, 2
- Do not close infected wounds. 2
- Do not delay medical care when systemic symptoms are present. 2
Follow-up Care
- Most patients with local symptoms only will recover completely within 24-48 hours. 1, 2
- Continue pain management with over-the-counter medications as needed for several days. 1, 2
- Follow-up within 24 hours either by phone or office visit is advised. 2
- Monitor for signs of secondary infection requiring prompt medical attention. 1