Why spiders bite people

Being crushed against a bedsheet by a human body just doesn't work well as a biting scenario despite what everyone thinks because spider fangs are underneath the spider. When pressed on from above, the spider may reflexively bite what it is standing on: the sheet, not your body. True spider bites which are rare events occur when a spider is trapped inside clothing or when someone foolishly puts a hand or other body part in a spider habitat without looking, or even more foolishly slaps at a spider that is crawling on them.

Skin bumps and sores noticed in the morning are generally caused by non-bite disease conditions: see this article for a partial list. Currently MRSA bacteria see this article are among the leading causes of alleged "spider bites.

Genuine spider bites in this situation are possible, but very rare. Spider Myths. Explore even more! You can limit the number of spiders in your home by having it sprayed with insecticide. Be sure to use only a licensed pest control company to do this. Insecticides carry their own risks, particularly if children, pets, or pregnant or nursing women are in the home.

There are 5 different species of widow spiders, including the black widow, in the U. Of these, only 3 are black. And only the black widow has the classic reddish-orange "hourglass" shape on its belly. The bite of any of the widow types can cause a fairly severe reaction. The black widow causes the most frequent and severe poisonings. Black widows are not aggressive spiders unless they are provoked. They generally live in dark, quiet, undisturbed areas in and around a home such as closets and basements.

If you are bitten by a black widow spider, the area of the bite may begin to swell and hurt after about a half hour.

The venom of a black widow spider is a neurotoxin. This means it affects the nerves and the brain. These are symptoms of a black widow spider bite:. In severe cases, a person may become unconscious or stop breathing.

Death from a black widow bite is extremely rare. If it does happen, it is more likely in children younger than 2 or in adults older than There are 12 species of recluse spiders, including the brown recluse, in the U. Only half of these are responsible for bites that have a major reaction in people.

Most of the spiders in this group have a violin or fiddle-shaped marking on the upper part of their body. The base of the violin is at the front of the head and the neck of the violin points toward the rear of the spider. In: Habif's Clinical Dermatology.

Elsevier; Accessed March 2, Thompson, DA. Spider bite. American Academy of Pediatrics; Auerbach PS, et al. Arthropod and mosquito bites and stings. In: Field Guide to Wilderness Medicine. Accessed March 3, Venomous spiders.

National Institute for Occupational Safety and Health. Brown recluse spider. Occupational Safety and Health Administration. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Share Flipboard Email.

Debbie Hadley. Entomology Expert.