All spiders have jaws and fangs that are designed to bite and deliver venom to their prey. However, with most of these spiders, their jaws and teeth are too small to puncture human skin. The venom of most spiders is not toxic to humans unless they have a compromised immune system or other medical condition. Pennsylvania does have a few spider species that are capable of biting humans and they include the wolf spider, various sac spiders and the southern black widow spider. If you believe you have been bit by a potentially dangerous spider, consult your physician immediately.
The wolf spider is a member of the genus Hogna and Pennsylvania is home to two of the biggest Hogna species and wolf spiders known as H. carolinensis and H. aspersa. Depending on the species, the wolf spiders in Pennsylvania can measure between 18 and 35 millimeters in length and are usually found in the soil and between boards, rocks and firewood outside. They are hunting spiders and are most often seen at night when they are on the hunt for prey. They will bite humans if they are trapped next to the skin, such as between clothes, or if they are handled. Their venom does not cause a serious reaction in humans and normally results in short-lived pain and redness.
A variety of sac spiders are found in Pennsylvania including the agrarian and the broad-faced. They range in size from 4 to 10 millimeters and can be found outside on foliage, under windowsills and in the corners of walls and ceilings within homes. They are known for biting humans and they have even been seen crawling across human skin biting repeatedly. According to the Pennsylvania State University’s College of Agricultural Sciences, the bite is very painful and can cause erythema, edema and severe itching. Some people can experience a more severe reaction to these spider bites that can include fever, malaise, muscle cramps and nausea. A necrotic lesion and ulceration might also occur at the site of the bite.
The southern black widow spider, or Latrodectus mactans, is a small spider measuring between 3/16 and 3/8 of an inch in length. They are shiny black in color and have a distinct red hourglass mark on their abdomen. These spiders can be found under rocks and in woodpiles. The bite of a black widow spider is painless when it occurs, however within two hours you might experience pain and tingling in your nerves and spine. The venom delivered in a bite from a black widow is a neurotoxin and can cause symptoms such as fever, chills, elevated blood pressure, burning in the skin, fatigue, difficulty breathing and muscle aches. Black widow bites are usually treated with Latrodectus antivenin and medications to counteract the symptoms. A bite is generally not fatal, though it can be in elderly patients and very young children.
Most spider bites will heal and go away on their own without medical treatment. However, if you experience fever, muscle aches, nerve pain or any other type of allergic reaction, seek medical attention immediately.
- Penn State College of Agricultural Sciences; Commonly Encountered Pennsylvania Spiders; 2006
- Penn State College of Agricultural Sciences; Wolf Spiders; 2006
- Penn State College of Agricultural Sciences; Agrarian Sac Spider; 2006
- Penn State College of Agricultural Sciences; Broad-faced Sac Spider; 2006
- Penn State College of Agricultural Sciences; Southern Black Widow Spider; 2006