Disease: Spider Bites
(Including Black Widow and Brown Recluse)

    Spider bites facts

    • Most spiders are harmless; the two exceptions in the U.S. are the black widow and brown recluse spiders.
    • Spider bites are actually rare occurrences, and most presumed cases of spider bites are likely due to another condition that mimics the symptoms of a spider bite.
    • Bites from most (non-poisonous) spiders cause local redness, irritation, and pain that usually can be treated at home.
    • Always seek emergency medical care for a presumed black widow or brown recluse spider bite.

    What are the symptoms of spider bites?

    Bites from most (non-poisonous) spiders cause local redness, irritation, and pain that usually can be treated at home using an over-the-counter pain reliever along with application of cooling packs or a wet cloth to relieve swelling. These local reactions usually resolve without treatment over a period of 7-10 days. Rarely, an individual can have an allergic reaction to a spider bite, even to a bite from a non-poisonous spider, but allergic reactions are more likely to be due to contact with a spider than from a spider bite.

    Black widow spider bite symptoms

    A black widow spider bite is said to feel like a pinprick, although victims may not realize that they have been bitten. Sometimes double fang marks may be seen at the location of the bite. The most common localized symptoms of a black widow spider bite are immediate pain, burning, swelling, and redness.

    Picture of the underside of a black widow spider and an egg sack Picture of a top view of a black widow spider

    Brown recluse spider bite symptoms

    The bite of a brown recluse spider leads to a mild stinging, followed by local redness and severe pain that usually develops within eight hours but may occur later. Some reports of brown recluse bites describe a blue or purple area around the bite, surrounded by a whitish ring and large red outer ring in a "bull's eye" pattern. A fluid-filled blister forms at the site and then sloughs off to reveal a deep ulcer that may turn black.

    Picture of a brown recluse spider. Note the violin pattern on the cephalothorax and light-colored hairless abdomen. Picture of a brown recluse spider Picture of a brown recluse spider head close-up

    Generalized symptoms of bites from black widow and brown recluse spiders may include:

    • fever,
    • nausea,
    • vomiting ,
    • headache,
    • abdominal pain,
    • joint pain or stiffness,
    • overall feelings of malaise,
    • rash, and
    • muscle cramping or tension.

    While black widow spider bites are hardly ever fatal, rare deaths have occurred from brown recluse spider bites and are more common in children than in adults.

    If a spider was not observed inflicting the bite, it is difficult if not impossible to determine whether a spider bite occurred, since many conditions of the skin may produce the same symptoms as a spider bite. Streptococcal and Staphylococcal infections, early lesions of herpes simplex or zoster, burns, stings or bites from other arthropods or insects (including fleas, bedbugs, mosquitos, biting flies, ants, and ticks), thorn injury, and early Lyme disease all may be characterized by skin findings similar to those from a spider bite. Spiders rarely bite people, and only if threatened. People often thing they have spider bites when the irritation is from another cause.

    Are spider bites dangerous?

    Most spiders do not have mouth parts strong enough to penetrate human skin, and the majority of spiders found in the U.S. and are actually harmless. There are two notable exceptions, the black widow spider and the brown recluse spider, which are both dangerous to humans. Spider bites are fortunately uncommon. In many cases, presumed spider bites are actually due to another skin condition or an insect sting.

    The black widow and brown recluse spiders are more common in the southern states of the U.S. They prefer warm, dry climates and undisturbed areas such as basements, closets, woodpiles, attics, or under sinks. The black widow spider is a small, black, shiny spider with a red hourglass marking on its belly. The brown recluse spider is sometimes termed a "violin spider." It is about an inch long and has a marking resembling a violin on the upper part of its back. Bites from both the black widow and brown recluse spiders are dangerous to humans and require prompt emergency medical care.

    What should you do if you are bitten by a spider?

    • Wash the site of the spider bite well with soap and water.
    • Apply a cool compress or ice pack over the spider bite location.
    • Over-the-counter pain relievers may be used to relieve symptoms. (Remember, do not give aspirin to children; use acetaminophen or ibuprofen instead).
    • Call the doctor or seek emergency treatment if the victim is a young child, if you think the bite may have been from a black widow or brown recluse spider, if any signs of an allergic reaction occur, if the bite area becomes infected, or if the victim develops a rash or severe illness.
    • If possible, retrieve the spider and bring it with you to the health care practitioner so that it can be definitively identified.
    • A tetanus booster shot may be necessary, depending upon the date of the patient's last immunization.

    Are spider bites dangerous?

    Most spiders do not have mouth parts strong enough to penetrate human skin, and the majority of spiders found in the U.S. and are actually harmless. There are two notable exceptions, the black widow spider and the brown recluse spider, which are both dangerous to humans. Spider bites are fortunately uncommon. In many cases, presumed spider bites are actually due to another skin condition or an insect sting.

    The black widow and brown recluse spiders are more common in the southern states of the U.S. They prefer warm, dry climates and undisturbed areas such as basements, closets, woodpiles, attics, or under sinks. The black widow spider is a small, black, shiny spider with a red hourglass marking on its belly. The brown recluse spider is sometimes termed a "violin spider." It is about an inch long and has a marking resembling a violin on the upper part of its back. Bites from both the black widow and brown recluse spiders are dangerous to humans and require prompt emergency medical care.

    What should you do if you are bitten by a spider?

    • Wash the site of the spider bite well with soap and water.
    • Apply a cool compress or ice pack over the spider bite location.
    • Over-the-counter pain relievers may be used to relieve symptoms. (Remember, do not give aspirin to children; use acetaminophen or ibuprofen instead).
    • Call the doctor or seek emergency treatment if the victim is a young child, if you think the bite may have been from a black widow or brown recluse spider, if any signs of an allergic reaction occur, if the bite area becomes infected, or if the victim develops a rash or severe illness.
    • If possible, retrieve the spider and bring it with you to the health care practitioner so that it can be definitively identified.
    • A tetanus booster shot may be necessary, depending upon the date of the patient's last immunization.

    Source: http://www.rxlist.com

    A black widow spider bite is said to feel like a pinprick, although victims may not realize that they have been bitten. Sometimes double fang marks may be seen at the location of the bite. The most common localized symptoms of a black widow spider bite are immediate pain, burning, swelling, and redness.

    Source: http://www.rxlist.com

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