Spider Bites

Spiders coexist with humans, rarely transmit communicable diseases, and play a role in the ecosystem as they consume mosquitoes and flies which are responsible for spreading human diseases. However, occasionally spider bites can cause allergic reactions and bites by the black widow and brown recluse spiders can be very dangerous. You can prevent spider bites by taking simple measures.

Only a few spiders are dangerous to humans

There are more than 30,000 species of spiders, most of them poisonous, but only a few species (approximately 200) are dangerous to humans. This is because most spider bites do not fully penetrate human skin due to their short fangs and fragile mouthparts. In the Unites States, most spiders are harmless with the exception of the black widow and the brown recluse spiders. Both of them prefer warm climates and dark places and usually live in dry, messy, undisturbed areas, such as closets, under sinks, behind furniture and woodpiles. 

• The black widow spider is known for the red hourglass marking on its belly and is about one-half inch long and has long legs. They are shy by nature and bite only when trapped, sat on, or accidentally touched.
• The brown recluse spider is about half to one inch long and all brown except for a dark mark in the shape of a violin on its head. These spiders will often move slowly and then make a sudden fast move for a couple of inches, then return to the previous sluggish pace. They are easily trapped against one’s skin by clothing and bed sheets. There are no brown recluse spiders in California.

Signs and symptoms of spider bites

Spiders rarely bite people unless threatened, and most bites are harmless causing a reaction similar to that of a bee sting, including redness, itching, pain and minor swelling at the site. Some people have more severe reactions to bites and infants and children may be more affected than adults. Serious injuries from spider bites can include severe wounds caused by brown spiders and body wide poisoning caused by widow spiders. 

A bite by a black widow spider sometimes feels like a little pinprick. Hours later, the venom (poison) can cause painful cramps starting in the muscles around the bite and then spread. Other symptoms can include weakness, nausea, vomiting, sweating, and headache. 

Bites by recluse spider are mostly minor with little or no necrosis – the premature death of cells and living tissue. However, a small number of bites produce severe necrosis of the skin, and sometimes affect the whole body with damage to organs and occasional deaths. 

Many people falsely assume that they were bitten by a spider when they really have another disorder such as a skin infection, bites by other insects or exposure to chemical or physical agents.

Tips for Preventing Spider Bites

• Be careful in areas where spiders like to spend time.
• Do not let your children play around rock piles or wood piles.
• Wear gloves when you are working outside in the yard in big piles of logs or leaves.
• Shake out your shoes before putting them on, if kept in a mudroom or garage.
• Shake out blankets and clothing that have been stored in the attic or the basement, or if they have been in a closet for long time.
• Look carefully behind furniture before reaching around for cleaning.

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

Wash the bite area well with soap and water. Apply an ice pack or a wet compress to the area. If needed, use over-the-counter pain medicine. Seek medical treatment for small children and adults with severe symptoms. If you suspect a bite by a black widow or brown recluse spider, apply ice to the bite site and take your child to the emergency room.