Medical Encyclopedia

 

Medical Encyclopedia

Other encyclopedia topics:  A-Ag  Ah-Ap  Aq-Az  B-Bk  Bl-Bz  C-Cg  Ch-Co  Cp-Cz  D-Di  Dj-Dz  E-Ep  Eq-Ez  F  G  H-Hf  Hg-Hz  I-In  Io-Iz  J  K  L-Ln  Lo-Lz  M-Mf  Mg-Mz  N  O  P-Pl  Pm-Pz  Q  R  S-Sh  Si-Sp  Sq-Sz  T-Tn  To-Tz  U  V  W  X  Y  Z  0-9 

Black widow spider

Contents of this page:

Illustrations

Arthropods, basic features
Arthropods, basic features
Arachnids, basic features
Arachnids, basic features
Black widow spider
Black widow spider

Definition    Return to top

The black widow spider (Latrodectus mactans) has a shiny black body with a red hourglass-shape on the belly area. The bite of a black widow spider is poisonous.

This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local emergency number (such as 911) or the National Poison Control Center at 1-800-222-1222.

Poisonous Ingredient    Return to top

The venom of the black widow spider contains poisonous chemicals that make people sick.

Where Found    Return to top

Black widows are found throughout the United States 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    Return to top

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.

The following symptoms can also occur:

Pregnant women may have contractions and go into premature labor.

Home Care    Return to top

Seek immediate emergency medical treatment. 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    Return to top

Determine the following information:

Poison Control    Return to top

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 United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

See: Poison control center - emergency number

What to Expect at the Emergency Room    Return to top

The health care provider will measure and monitor the patient's vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms may be treated with a variety of therapies, including:

In severe cases, anti-venin medication to reverse the effect of the poison will be given. However, this drug can cause serious allergic reactions.

Outlook (Prognosis)    Return to top

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, the extremely ill, and the elderly may not survive a bite.

References    Return to top

Auerbach PS. Wilderness Medicine. 4th ed. St. Louis, Mo: Mosby; 2001.

Ford MD. Clinical Toxicology. 1st ed. Philadelphia, Pa: WB Saunders; 2001.

Marx J. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 5th ed. St. Louis, Mo: Mosby; 2002.

Update Date: 2/17/2009

Updated by: A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz. Previously reviewed by Eric Perez, MD, Department of Emergency Medicine, St. Luke's-Roosevelt Hospital Center, New York, NY. Review provided by VeriMed Healthcare Network (10/17/2008).

A.D.A.M. Logo

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2009, A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.