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 wound thoroughly with large volumes of warm or room temperature water until no foreign matter remains 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
- Elevate the affected area to reduce swelling and accelerate healing 2
- Apply antibiotic ointment and cover with a clean occlusive dressing to improve healing and reduce infection risk 1, 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
Swelling in the first 24-48 hours is caused by inflammatory mediator release, NOT infection—do not prescribe antibiotics prophylactically. 1, 2 This is one of the most common errors in spider bite management. Universal antibiotic prophylaxis is not recommended for bite wounds 2.
When Antibiotics ARE Indicated
Antibiotics should only be prescribed if signs of secondary bacterial infection develop 2:
- Progressive erythema extending beyond the initial bite site 2
- Purulent discharge 2
- Systemic signs of infection (fever, elevated white blood cell count) 2
For confirmed secondary infection, use trimethoprim-sulfamethoxazole or doxycycline as first-line therapy to cover MRSA 2. Alternative options include clindamycin if local resistance patterns permit 2.
When to Seek Emergency Medical Care
Patients should seek immediate medical attention if any of the following occur 1, 2:
- Difficulty breathing, bronchospasm, or laryngospasm (suggests anaphylaxis) 2
- Rapidly progressive swelling involving face, lips, tongue, or throat 2
- Muscle rigidity, dizziness, confusion, or syncope 1, 2
- Severe pain extending beyond the bite site or uncontrolled by over-the-counter medications 1, 2
- Development of an open wound 1
Special Considerations for Venomous Spiders
Brown Recluse Spider Bites
The primary treatment for brown recluse bites is rest, ice compresses, and delayed surgical debridement—not immediate surgery. 2 These bites can cause painful ulcerated wounds that progress over days to weeks, sometimes with hemolysis and rhabdomyolysis 2, 3. Dermonecrosis typically develops within 72-96 hours 3. Some evidence suggests dapsone may be beneficial, though this remains controversial 3.
Black Widow Spider Bites
Black widow bites primarily produce muscle cramping, pain, and neuromuscular symptoms rather than significant skin changes 3, 4. Treatment includes analgesics, benzodiazepines for muscle spasm, and supportive care 4. Antivenom is available but not widely accessible in the United States and is reserved for severe, refractory cases 4.
What NOT to Do
These interventions are ineffective and potentially harmful 1, 2:
- Do not apply suction to the bite site 1, 2
- Do not apply tourniquets or pressure immobilization bandages, as they may worsen tissue injury 1, 2
- Do not assume antibiotics are needed for swelling around the bite site 1, 2
- Do not close infected wounds 2
Expected Recovery Timeline
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 by phone or office visit is advised 2. Monitor for signs of secondary infection during the recovery period 1, 2.