Spider Bite Treatment
Immediate First Aid
For most spider bites, treatment consists of thorough wound irrigation with copious warm water, ice application with a barrier between ice and skin, over-the-counter pain medications, antibiotic ointment, and a clean occlusive dressing—antibiotics are NOT routinely needed for initial swelling. 1, 2
Initial Wound Care Steps
- Irrigate the bite wound thoroughly with large volumes of warm or room temperature potable water until no foreign matter remains 1, 2
- Apply ice to the bite site for local pain relief, always using a clean barrier between ice and skin to prevent cold injury 1, 2
- Remove rings and constricting objects immediately from the affected extremity, as swelling may develop 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
- Use over-the-counter acetaminophen or NSAIDs for pain control 1, 2
- Apply topical lidocaine 5% 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
Antibiotics ARE Indicated Only When:
- Progressive erythema extends beyond the initial bite site 2
- Purulent discharge develops 2
- Systemic signs of infection appear, such as fever or elevated white blood cell count 2
- For confirmed secondary bacterial infection, use trimethoprim-sulfamethoxazole or doxycycline as first-line oral therapy to cover MRSA 2
- Alternative options include clindamycin if local resistance patterns permit 2
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—these may worsen tissue injury 1, 2
- Do not assume antibiotics are needed for swelling around the bite site 1, 2
When to Seek Emergency Medical Care
Call emergency services immediately if systemic symptoms develop: 1, 2
- Difficulty breathing, bronchospasm, or laryngospasm
- Dizziness, confusion, or syncope
- Muscle rigidity or severe cramping
- Rapidly progressive swelling involving face, lips, tongue, or throat (angioedema)
- Hypotension or signs of anaphylaxis
Seek urgent medical evaluation if: 1, 2
- Pain extends beyond the bite site or becomes severe
- Pain is not controlled by over-the-counter medications
- An open wound develops
- Signs of infection appear
Special Considerations for Venomous Spider Bites
Brown Recluse Spider Bites
- Can cause painful ulcerated wounds that progress over days to weeks, sometimes with hemolysis and rhabdomyolysis 2
- Primary treatment remains rest, ice compresses, and delayed surgical debridement (several weeks after the bite) 2, 3
- Dapsone may be considered in severe cases 3
- Hyperbaric oxygen therapy may be valuable for chronic nonhealing wounds even months after the bite 4
Black Widow Spider Bites
- Produce minimal skin changes but cause muscle cramping, pain, and neuromuscular symptoms 3, 5
- Treatment includes pain control, muscle relaxants (methocarbamol, diazepam), and calcium gluconate 3, 5, 6
- Specific antivenom is available for severe cases 3, 5
Expected Recovery Timeline
- Most patients with local symptoms only 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 by phone or office visit is advised 2
- Monitor for signs of secondary infection requiring prompt medical attention 1, 2