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Black Widow Spider Bite

Black Widow Spider Bite Treatment

Self-Care at Home

The options for home care are somewhat limited. Both cold and warm compresses have been recommended, as have hot baths. Certainly, a hot bath would seem to be of value because the pain is due primarily to muscle spasm. Obviously, over-the-counter pain relievers such as acetaminophen and ibuprofen may be of value in mild cases. Folk remedies have not proven to work. 

Medical Treatment

In general, extensive medical evaluation is not necessary. The exceptions are when the history of a black widow bite is not clear, if the bite was not witnessed, and when associated symptoms require the exclusion of more serious disorders, such as heart attack. 

Medications

In general, the person bitten by a black widow spider, who has pain severe enough to seek treatment at an Emergency Department, will require narcotic pain relief. Muscle relaxants given by injection may also be of value. Although calcium gluconate given through an IV has long been advocated, it does not seem to produce much relief of symptoms.

Use of antivenin

The antivenin available for treatment of black widow spider bites is derived from horse serum. The venom produced by various species of spiders is similar, so the antivenin prepared against one venom is effective against the others. Antivenin is produced by gradually increasing injections of the specific venom in a horse. The horse naturally produces the antivenin used in humans.

Symptoms are often not easily relieved, even with narcotics. Some experts recommend that antivenin be used in any severe bite because 1 vial of the antitoxin produces significant and rapid relief of symptoms. It can even be used if there is delay in reaching the hospital. Yet other sources recommend that antivenin be used only in children, the elderly, and those with severe underlying medical conditions.

The obvious risk for using antivenin is allergic reaction to horse serum, and the bitten person must be skin-tested for this possibility. Although delayed serum sickness is common when horse serum is used to treat rattlesnake bites, it is uncommon when used to treat black widow spider bites (probably because of the low dose needed for relief).

Be aware, however, that this antivenin may not be readily available at most hospitals; there may be some delay or difficulty in obtaining it when needed.

Of interest: The use of the black widow antivenin might sensitize the person for later use of rattlesnake antivenin. Obviously, the physician should discuss lifestyle habits that might affect the person's risk of incurring a snakebite in the future. In many areas, black widow bites are much more common than rattlesnake bites.

Next Steps - Follow-up

In general, follow-up is only necessary in cases where antivenin is used. Although serum sickness is uncommon with single-vial doses of horse serum, it may occur 7-12 days after exposure and is characterized by skin lesions, fever, pain in the joints, and swollen lymph glands. The symptoms may occur sooner in a sensitized person. The process is self-limited, goes away in 2-3 weeks, and may be treated with antihistamines and steroids.

WebMD Medical Reference from eMedicineHealth

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