Treatment for Black Widow Spider Bites
Emergency medical services should be called immediately if a person bitten by a black widow spider develops systemic symptoms such as difficulty breathing, muscle rigidity, dizziness, or confusion. 1
Initial Assessment and First Aid
- Black widow spider (Latrodectus mactans) bites cause severe crampy pain, muscle rigidity, diaphoresis, and hypertension; they typically do not cause local tissue injury, though a rash is sometimes observed around the bite site 1
- Seek medical care if pain extends beyond the bite site, becomes severe, is not controlled by over-the-counter pain medications, or if systemic symptoms develop 1
First-Line Treatment Options
- First aid treatment involves localized wound care and over-the-counter analgesics for pain 1
- Over-the-counter acetaminophen and nonsteroidal anti-inflammatory agents can be used to alleviate local pain 1
- If the skin is intact, topical lidocaine can be useful for pain relief 1
- Ice application can be useful for local pain relief 1
Advanced Treatment Options
- For severe envenomation with significant pain unresponsive to standard therapy, antivenom (Antivenin Latrodectus mactans) is the most effective treatment 2, 3
- Antivenom rapidly resolves symptoms but is often withheld due to concerns about hypersensitivity reactions 2, 4
- Opioid analgesics combined with muscle relaxants such as benzodiazepines may provide temporary symptomatic control for severe pain and muscle rigidity 3, 5
Clinical Manifestations to Monitor
- Latrodectism (black widow envenomation syndrome) is characterized by:
- Symptoms typically last for 1-3 days 3
Special Considerations
- The very young, very old, and those with underlying health conditions may be at higher risk for severe reactions 1
- While rare, death can occur in untreated severe cases, particularly in vulnerable populations 5
- A new purified F(ab)2 fragment antivenom (Analatro®) has been developed with potentially fewer adverse reactions than the traditional equine-derived product 3
Common Pitfalls to Avoid
- Delaying medical care when systemic symptoms are present 1
- Failing to recognize the characteristic syndrome of latrodectism, which may lead to misdiagnosis 5
- Underestimating the severity of envenomation based solely on local findings at the bite site 1
- Withholding antivenom in cases of severe envenomation due to exaggerated fears of allergic reactions 2