Widow Spider Bite

There are more than 30,000 recognized spider species in the world. But only about 100 defend themselves aggressively and have fangs long enough to penetrate human skin and can cause harm to humans. Bites of the most spiders are painful but do not cause any harm. The venom that spiders use to hunt their prey can cause necrosis of skin and systemic toxicity. Bites of spiders like brown recluse spiders, widow spiders and very few other species can be life threatening. Specific treatment for spider bite like widow and brown recluse spiders is available, so offending spider should be tried to identify. In many cases it is seen that injury is by something else but spiders are attributed as the offender.ID-10048350

Widow Spider Bite:

The scientific name of widow spider is Latrodectus mactans. The bite of the female widow spider is dangerous and notorious due to its potent neurotoxin. The black widow spider is found in all of USA except Alaska. It is more common in Southeastern parts of USA. It is about 5 cm in length with a body of one cm. It is shiny black in color and has a red hourglass marking in the abdomen. The red widow and the brown widow are other dangerous types of widow spiders.

Bites are most common during summer and early autumn when their web is disturbed or when they are trapped or provoked. They spin their webs in logs, plants, rock piles, under stones or in dark areas like garages or outhouses. Buttocks are the site of bite if the person sits on a spider. It goes unnoticed at first or may be thought as a sharp pinprick. If examined properly two small red marks will be seen and there will be swelling around the marks. Toxin which is the most active component of the venom is yellowish and oily in color and may not cause any problem or it may be cause serious toxicity by binding irreversibly to nerves and cause release and depletion of acetylcholine, norepinephrine and other neurotransmitters. In less than half hour painful cramps spread from bite site to large muscles of trunk and limbs. Symptoms like salivation, vomiting, high blood pressure, diaphoresis, breathing difficulties, high pulse rate, weakness, headache, anxiety, urinary retention, hyperreflexia, fasciculation, uterine contraction and premature labor can occur. Peritonitis may develop, which is suggested by rigidity of abdominal muscles and excruciating pain. But there may not be any pain on pressure to abdomen. In very weak and frail person, elderly and young person it may cause renal failure, respiratory arrest, cardiac arrest, brain hemorrhage and death. Excruciating pain may last for several weeks or it may subside in a day.

Treatment of Widow Spider Bite:

At first cleaning of the bite site with plain water, ice packing, and tetanus prophylaxis should be given. If there is high blood pressure it requires specific antihypertensive therapy because it can not be controlled symptomatically. Specific equine antivenin is available but due to its high risk of anaphylaxis and serum sickness it should be reserved for serious cases only. The equine antivenin is administered intravenously relieve pain rapidly. One or two vials are usually sufficient.

Preventive measures like wearing full sleeve heavy shirts, full trousers (not half pant or bermuda), and hand gloves should be kept in mind while working outdoor and in dark areas indoor in the localities where widow spiders are commonly found.

 

Image courtesy of [ahmet guler] at FreeDigitalPhotos.net




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