Definition
This poisoning is from a bite by a black widow spider (Latrodectus mactans).
Poisonous Ingredient
The venom of the black widow spider contains neurotoxins that make people sick.
Where Found
Black widows are found throughout the U.S., but predominantly in the South and West. They are usually found in barns, sheds, stone walls, fences, woodpiles, porch furniture, and other outdoor structures.
Symptoms
This first symptom is usually pain similar to a pinprick. This sensation is felt when the bite is actually made. Some people may not feel it. There may be minor swelling and redness.
Fifteen minutes to an hour later, a dull muscle pain spreads from the bite area to the entire body.
- If the bite is on the upper body, you will usually feel most of the pain in your chest.
- If the bite is on your lower body, you will usually feel most of the pain in the abdomen.
The following symptoms can also occur:
- Muscle weakness
- Numbness
- Increased sweating
- Increased salivation
- Difficulty breathing
- Nausea and vomiting
- Restlessness
- Anxiety
- Headache
- High blood pressure
Pregnant women may have contractions and go into premature labor.
Home Treatment
Seek immediate emergency medical treatment. Then, wrap ice in a washcloth or similar material and place it on the bite area. Leave it on for 10 minutes and then off for 10 minutes. Repeat this process.
Before Calling Emergency
Determine the following information:
- Patient's age, weight, and condition
- Time the bite occurred
- Area where the bite occurred
- Type of spider, if possible
Poison Control, or a local emergency number
The National Poison Control Center (1-800-222-1222) can be called from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. They will give you further instructions.
This is a free and confidential service. All local poison control centers in the U.S. use this national number.
What to expect at the emergency room
The symptoms may be treated with a variety of therapies, including:
- Pain medication
- Muscle relaxants
- Blood pressure drugs
In severe cases, anti-venin medication will be given. This drug may cause a dangerous reaction in people who are allergic to horses.
Expectations (prognosis)
Severe symptoms usually go away within 2 to 3 days, but milder symptoms may persist for several weeks. Death in a normally healthy individual is very rare. Young children may not survive a bite.
References
Marx J. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 5th ed. St. Louis, Mo: Mosby; 2002: 794-795.
Auerbach PS. Wilderness Medicine. 4th ed. St. Louis, Mo: Mosby; 2001:829-832.
Reviewed By: Stephen C Acosta, MD, Department of Emergency Medicine, Portland VA MedicalCenter, Portland, OR. Review provided by VeriMed Healthcare Network.
