Spiders are unfairly implicated by doctors and laypeople alike for attacks on humans, but Spiders bites rarely happen for a variety of reasons including:
Spiders Don’t gain Any Benefit from Biting People
Biting a person does not benefit a spider, it only wastes precious venom. Other biters (Mosquitos, ticks, Chiggers, and Bedbugs) bite us because our blood or other fluids supply them with food. Spiders have no interest in our fluids; they feed on insects or other arthropods. Spiders bite people only in defense and even that rarely happens.
Most Spiders Couldn’t Bite People Even If They Wanted To
Of approximately 3000 different spiders in the United States, only a small number have fangs long enough and strong enough to break skin. Of those biters, the Centers for Disease Control considers that only two have dangerous bites: The brown recluse spider and the black widow spider.
Not Every Part of The US Even Has Dangerous Spiders.
It has been estimated that 60% of alleged brown recluse spider bites occur in areas where no brown recluse spiders are known to exist.
About 80% of Spider Bites Are Diagnosed Incorrectly
There are many medical conditions that are easily misdiagnosed as spider bites, and there are a number of other arthropods whose bites are blamed on spiders.
Spider experts feel that the diagnosis of “spider bite” should only be made when a spider is caught in the act of biting, or is otherwise reliably associated with the wound. Identification of the spider by an expert is also important since there are non-poisonous spiders that closely resemble poisonous spiders, and vice versa. Without spider confirmation, the diagnosis of spider bite should not be considered.
There is one clue as to whether a bite is from a spider or not. A spider bite is distinguished by two small punctures, set close together, from the spider’s two fangs. Most insects leave a single puncture mark when they bite. However, once the bite becomes swollen it is impossible to see the puncture marks. Because spiders only bite once, a person with multiple bites was not bitten by a spider. Likewise, when there are multiple bites in the same house or location, spiders are not the culprits. The unfortunate outcome of misdiagnosed spider bites is that people with serious medical conditions may go un-diagnosed or untreated when the easier diagnosis of spider bite is made. There are at least 30 different medical conditions that can cause skin lesions and have been misdiagnosed as a spider bite, including herpes, bed sores, basal cell carcinoma, diabetic ulcers, and Lyme disease. Perhaps the most important recent bite confusion is with MRSA, a sometimes deadly staph infection that causes draining skin abscesses and is becoming more and more common.
This doesn’t mean people can’t be bitten by a spider. But they should understand that a spider bite is extremely unlikely and should first ask themselves “what else could it be?” instead of assuming it’s a spider bite.