Brown Recluse Spiders in Pennsylvania

Brown recluse spiders thrive in warm, dry environments and are most common in the south-central United States. True to their name, they prefer to hide in out-of-the-way spaces, such as woodpiles, crevices between rocks and beneath the bark of dead trees. Sometimes they are encountered in seldom-used sheds and other outbuildings, as well as in basements, drawers and closets.

When brown recluse spiders are found in Pennsylvania, they usually were transported into the state accidentally in boxes, luggage or firewood. These spiders avoid interactions with humans whenever possible but may bite when threatened or accidentally handled.

A brown recluse spider is chocolate brown with a body nearly 1/2 inch in length, not including legs. The spider has long, slender legs and three pairs of eyes. The most recognizable identifying mark on the brown recluse spider is a violin-shaped marking that is darker than the rest of the body and starts on the head segment right above the eyes, with the violin's "neck" portion pointing backward toward the abdomen.

Wolf spiders, which are common throughout Pennsylvania, are somewhat similar in appearance but have sturdier legs and lack the violin-shaped mark.

The initial bite of a brown recluse is sometimes painless, or it may be accompanied by a mild stinging sensation. A blisterlike sore or ulcer appears at the bite area about seven hours after the bite and is accompanied by itching or pain that ranges from mild to intense. Breakdown of tissue, also known as necrosis, occurs around the bite location sometimes one week or longer after the initial bite. It can take months to heal and varies in severity with the amount of venom injected during the bite. A whole-body reaction occurs rarely in individuals with sensitivity to the venom. Symptoms include fever, chills, nausea, vomiting, joint pain and a rash all over the body.

If you suspect you were bitten by a brown recluse, stay calm and restrict your movement. Apply ice or a cool, wet cloth to the bite area. Do not apply a tourniquet, which can result in further harm. Contact a doctor if you develop an open sore or a whole-body reaction. If it is possible to do so safely, capture the spider for identification by an expert.

Southern black widow spiders also reside in Pennsylvania. The body of the female southern black widow is about 1/2 inch long, but the spider can appear significantly larger with its legs outstretched. The male is much smaller, with a body length up to 1/4 inch, not including legs. The female is jet-black and displays a red hourglass shape on its underbelly while the male is typically black with white markings and red spots.

Southern black widows spin disorganized cobwebs in sheltered locations such as woodpiles and seldom-used buildings.

A black widow spider bite is usually fairly painless initially, but pain in the bite area develops within one to two hours, accompanied by symptoms that may include fatigue, nausea, chills, fever, muscle aches, elevated blood pressure and difficulty breathing.

Seek medical attention if you think you were bitten by a black widow spider.

Deaths from black widow bites are extremely rare, usually occurring in only very young and elderly people. According to the Children's Hospital of Philadelphia's website, "Most people recover completely as long as they obtain treatment, which includes pain relievers, fluids, tetanus shots and other measures. Antivenom is available and highly effective, but is used only for high-risk cases and multiple bites."