Although the black house spider can look intimidating because of its dark coloring, thick legs, and generally large size -- females average just under 1 inch -- they usually will not bite humans unless provoked or unless they feel as if they are in danger 1. While the bite of the black house spider is not usually lethal, it is venomous and can cause harmful and uncomfortable effects to the bitten victim 1. Unlike what its name suggests, black house spiders can be found inside homes and outside 1.

Common Short-Term Side Effects

Black house spider bites, while infrequent, usually cause an extensive amount of pain at the bite site 1. This pain is more likely to last more than 24 hours, due to the venomous nature of the black house spider 1. Local swelling and redness of the skin are also usually seen soon after a bite, and can last anywhere from a few hours to a couple of days, depending on the severity of the bite and the amount of venom injected. To identify the bite as a spider bite, look for small puncture wounds where there is pain and swelling.

Possible Short-Term Effects

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Some victims of black house spider bites may experience nausea, vomiting, and abdominal pain as a result of the spider venom 1. Lethargy and mild headaches soon after the bite may also occur.

Extraordinary Side Effects

While rare, there have been documented examples of dangerous and severe reactions to black house spider bites, especially if you are bitten more than once 1. Skin lesions, or arachnogenic necrosis, may appear soon after the bites, causing local blistering, ulcers and necrosis.

Treatment for Black House Spider Bites

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Although black house spider bites are not nearly as dangerous as other spider bites, they can still cause severe pain and some injury, especially to the local area 1. To reduce swelling and pain, thoroughly wash and ice the bite as soon as you notice it, and consider taking a pain-relieving medicine. If the pain and the swelling persist for an extended period of time, consult your doctor for further medical advice and treatment, especially if you begin to notice symptoms other than mere pain and swelling.