Spider Bite Treatment
For most spider bites, clean the wound thoroughly with copious amounts of water, apply ice for pain relief, cover with antibiotic ointment and a clean dressing, and monitor for signs of systemic symptoms or infection that would require urgent medical care. 1
Initial First Aid Management
Wound Care
- Irrigate the bite site thoroughly with large volumes of warm or room temperature water to remove any foreign matter 1
- Apply antibiotic ointment or cream and cover with a clean occlusive dressing, which reduces infection risk and promotes healing 1
- Place ice on the bite site for local pain relief, but use a barrier (such as a thin towel) between the cold container and skin to prevent tissue damage 1
Pain Management
- Use over-the-counter acetaminophen or NSAIDs for pain control 2
- Topical lidocaine 5% can be applied if the skin remains intact 2
What NOT to Do
- Do not apply suction to the bite site - this is ineffective and potentially harmful 1, 2
- Do not use tourniquets or pressure-immobilization bandages for spider bites, as these can worsen tissue injury 2
When to Seek Urgent Medical Care
Black Widow Spider Bites (Latrodectus species)
Call emergency services immediately if systemic symptoms develop, including: 2
- Difficulty breathing
- Muscle rigidity or severe muscle cramping (especially in thigh, shoulder, back, or abdomen)
- Dizziness or confusion
- Feeble pulse, cold clammy skin, or labored breathing 3
Hospital Treatment for Black Widow Bites
- Muscle relaxants and benzodiazepines for muscle spasm and pain control 4
- Intravenous calcium gluconate 10 mL of 10% solution, repeated as necessary to control muscle pain 3
- Morphine may be required for severe pain, though use cautiously given risk of respiratory depression 3
- Antivenom is available but not widely accessible in the United States; it may be considered for severe, refractory cases but can be deferred in healthy individuals aged 16-60 years 3, 4
Brown Recluse Spider Bites (Loxosceles species)
Seek medical attention if: 2
- Pain extends beyond the sting site or becomes severe
- Pain is not controlled by over-the-counter medications
- An open wound or necrosis develops within 72-96 hours 5
- Signs of systemic loxoscelism appear (massive hemolysis with minimal skin changes) 5
Medical Treatment for Brown Recluse Bites
- Rest, ice compresses, and antibiotics for necrotic lesions 5
- Dapsone may be used for dermonecrosis 5, 6
- Systemic corticosteroids may be helpful for rare systemic loxoscelism 5
- Delay surgical debridement for several weeks to allow full demarcation of necrotic tissue 5
- Hyperbaric oxygen therapy should be considered for nonhealing wounds, even months after the bite 7, 6
Signs of Secondary Infection Requiring Medical Attention
Do not assume antibiotics are needed for initial swelling, as this is typically caused by mediator release, not infection 2
Seek medical care if infection develops: 2
- Progressive erythema extending beyond the initial bite site
- Purulent discharge
- Systemic signs such as fever or elevated white blood cell count
Universal antibiotic prophylaxis is not recommended for bite wounds 2
Common Pitfalls
- Most spider bites are overdiagnosed - the actual spider bite often goes unnoticed for 4-6 hours, making diagnosis difficult 6, 4
- Capture of the offending spider is most helpful for definitive diagnosis and proper treatment 6
- In healthy adults aged 16-60 with black widow bites, antivenom use may be deferred in favor of muscle relaxants 3
- Brown recluse bites only rarely cause significant skin necrosis despite their reputation 4