Spider Bite Photo Gallery

A spider bite, also known as arachnidism, is an injury resulting from the bite of a spider. The effects of most bites are not serious.[1] Most bites result in mild symptoms around the area of the bite.[1] Rarely they may produce a necrotic skin wound or severe pain.[2]:455

Most spiders do not cause bites that are of importance.[1] For a bite to be significant, substantial envenomation is required. Bites from the widow spiders involve a neurotoxic venom which produces a condition known as latrodectism.[3] Symptoms may include: pain which may be at the bite or involve the chest and abdomen, sweating, muscle cramps and vomiting among others.[1] Bites from the recluse spiders cause the condition loxoscelism, in which local necrosis of the surrounding skin and widespread breakdown of red blood cells may occur.[4] Headaches, vomiting and a mild fever may also occur.[4] Other spiders that can cause significant bites include: the Australian funnel web spiders[5] and the South American wandering spider.

Efforts to prevent bites include clearing clutter and the use of pesticides.[1] Most spider bites are managed with supportive care such as NSAIDs (including ibuprofen) for pain and antihistamines for itchiness.[6] Opioids may be used if the pain is severe.[6] While an antivenom exists for black widow spider venom it is associated with anaphylaxis and therefore not commonly used in the United States.[6] Antivenom against funnel web spider venom improves outcomes.[1] Surgery may be required to repair the area of injured skin from some recluse bites.[6]

Spider bites may be overdiagnosed or misdiagnosed. Historically a number of conditions were attributed to spider bites. In the Middle Ages a condition claimed to arise from spider bites was tarantism, where people danced wildly. While necrosis has been attributed to the bites of a number of spiders, good evidence only supports this for recluse spiders.