Common house spiders often raise questions about their potential to bite and the effects on human health. This article provides clear information on common house spiders, their behavior, the rare instances of bites, and appropriate responses.
Understanding Common House Spiders
Several spider species are commonly found in North American homes, including the American house spider (Parasteatoda tepidariorum), the barn funnel weaver (Tegenaria domestica), and the giant house spider (Eratigena atrica). The American house spider typically has a round abdomen and can be gray or brown, sometimes with white markings, usually measuring less than a quarter of an inch. They create tangled, messy webs in undisturbed, dark areas like basements and corners.
Barn funnel weavers are brown or gray, measuring 7 to 18 millimeters, with males often smaller but having longer legs. Their distinctive funnel-shaped webs are found in corners of rooms or cluttered spaces, preferring dark, cool, and moist environments. Giant house spiders are larger, with females reaching around 18mm and males about 13mm, featuring long, hairy legs and a brownish-grey body with a chevron pattern on the abdomen. These spiders are generally reclusive, preferring to hide in dark corners, attics, and basements.
When and Why Bites Occur
Common house spiders can bite humans, but such incidents are infrequent. Spiders possess venom to subdue their prey, which are typically much smaller insects, not humans. Most spiders are not aggressive towards people, and their fangs are often too small to effectively puncture human skin.
Bites usually occur defensively when a spider feels threatened, such as when it is accidentally trapped against skin. This might happen if a spider is pressed against the body when putting on clothes, rolling over in bed, or handling items where a spider is hiding. Spiders do not actively seek to bite humans; they prefer to retreat or feign death if disturbed.
Recognizing and Treating a House Spider Bite
A bite from a common house spider typically results in mild, localized symptoms. These can include a raised red bump, some redness or irritation, and itching or mild swelling at the bite site. The symptoms are often similar to those caused by other insect bites, such as a mosquito bite.
For treating a common house spider bite, basic first aid is usually sufficient. Clean the bite area gently with mild soap and water. Applying a cool compress or an ice pack to the affected area for 15 minutes each hour can help reduce pain and swelling. Over-the-counter pain relievers can be taken if needed, and antihistamines may help alleviate itching.
Medical attention is rarely required for common house spider bites, but it is advisable if there are signs of infection, such as worsening redness, spreading inflammation, or pus. Seek immediate medical care if you experience severe pain, abdominal cramping, difficulty breathing, or symptoms of an allergic reaction like hives or swelling of the face, lips, or tongue. These more severe reactions are typically associated with bites from more dangerous spiders like black widows or brown recluse spiders, which are distinct from common house spiders.
Living Harmoniously with House Spiders
Common house spiders often play a beneficial role in the indoor environment by preying on various household pests like flies, mosquitoes, ants, and cockroaches. This natural pest control can reduce the need for chemical pesticides inside the home. Spiders can access hidden spaces, such as high corners or behind furniture, where they build webs to trap insects.
To minimize accidental encounters, practical measures can be taken. Sealing cracks and crevices in walls and foundations limits their entry points. Reducing clutter in basements and attics also makes these spaces less appealing. Leaving them undisturbed allows them to continue their beneficial role.