Spider Bites In the Pacific Northwest

There is much confusion regarding poisonous spiders found in the Pacific Northwest (PNW). This confusion extends, in many cases, even to the medical community. Only four spiders of medical importance occur in the PNW. Two of these, sac spiders in the genus Cheiracanthium, are rarely encountered. The other two, the aggressive house spider, or hobo spider, and black widow spider occur commonly in association with human activity and present a real danger in terms of bites.

However, many insect/spider bites reported in the PNW are, unfortunately, attributed to a spider that does not even occur here, namely the brown recluse spider. While the bite of the aggressive house spider is similar (see below), the brown recluse spider does not naturally occur in the PNW. The only known cases of this spider have been linked to people moving into the PNW from areas of known distribution.

The following characteristics should help to separate these spiders. The black widow spider (Latrodoctus sp.) occurs in the PNW generally in dry, undisturbed areas such as firewood piles, old lumber, dry crawl spaces, bales of hay, etc. The adult female is 1-1/2 inch in diameter, including legs, jet black with red markings on the underside of her abdomen. Males and immatures may be striped white or yellow. This spider is secretive, not aggressive, and rarely causes bite injuries. The venom is neurotoxic and may lead to systemic effects, sometimes even death.

Aggressive house spider (Tegenaria agrestis) is common in the PNW in and around houses, barns and sheds. It is a member of the funnel-web spider group. This is a relatively large spider (body size, excluding legs 3/8" - 5/8"; 1" - 1-3/4" including legs) with long, hairy legs and chevron-shaped abdominal markings. The venom is necrotic, causing open, localized wounds that may be slow to heal. Males may be more venomous than females and become quite common in mid-summer through the fall during the mating season. Despite its aggressive nature, however, reported bites from this spider are relatively rare. There are several closely related species that look very similar but whose venom is not as toxic.
 

---

Spider Bite Treatment 

Before beginning spider bite treatment, a person has to be sure that he’s been bitten by a spider. Someone may develop such symptoms as swelling, redness, itching, and pain after being bitten by a spider, but other insects can cause the same reaction. Even worse, the bite of the brown recluse spider can cause a very nasty sore, but many don’t go to the doctor for at least a few days after noticing the bite. This can make it difficult to determine what actually bit the patient.

If a person is sure he’s been bitten by a spider, he may want to perform some type of home care. However, there aren’t any specific first aid spider bite treatments. He may apply an anti-itch cream, a cold compress, or an analgesic lotion to relieve the pain or itching. An oral pain medication, such as acetaminophen or ibuprofen, may be helpful as well.

Many people worry most about bites inflicted by black widow and brown recluse spiders; a black widow spider may deliver a bite that feels like a prick from a tiny needle. The unlucky recipient of a bite from this spider may notice a bit of swelling in the area and may also observe some light-looking red marks. The obvious trouble begins after a few hours, when the person begins to feel severe pain and notice stiffness. He may also notice such symptoms as chills, fever, nausea, and pain in the abdominal area; he should seek emergency spider bite treatment from a local hospital or urgent care facility, which may include the use of ant venom. On the way to the hospital, it may help to apply a tight bandage above the bite to impair the spread of venom.

When the brown recluse spider bites, the bite area may sting a bit. After a time, it may become reddened, and intense pain may follow several hours later. Typically, a blister develops at the bite site and fills with fluid, eventually developing into an ulcer that is large and deep. Though rare, these bites can lead to death, particularly when children are bitten. If bitten by this spider, it is best to tie a bandage above the bite area to slow down the spread of the spider’s toxic venom, and then seek medical help with spider bite treatment.

 

Pasted from <http://www.wisegeek.com/what-should-i-know-about-spider-bite-treatment.htm>

 

 

 

---

 

 

How to Identify a Brown Recluse Bite

 

 

 

By Rose Kivi



CDC/PHIL

Because so many spider bites look the same, it is difficult to tell the difference between a brown recluse spider bite and a bite from another spider. Usually, a person is not aware that she is being bit by a spider. Of course, if you see a brown recluse spider biting you, then you can be sure that you have indeed been bitten by a brown recluse. Otherwise, the best approach to identifying a brown recluse spider bite is to keep an eye on the development of the bite.

 

Most brown recluse bites are not serious. A study conducted at a southeastern U.S. university hospital found that the majority of brown recluse bites did not cause serious symptoms or long-lasting effects.

Instructions

Difficulty: Challenging

Step 1

Look at the bite. At the beginning, a brown recluse spider bite appears as a small, white blister that is surrounded by a red ring. There may be a white ring surrounding the red ring. A few hours after the bite, the swollen red part of the skin feels hard.

Step 2

Determine if the spider bite is causing more pain than a normal spider bite would. Though not all brown recluse bites cause pain, many do. Pain symptoms usually develop about 10 minutes after the bite. Symptoms of pain can range from a slight to severe sting. If severe pain is present, see a doctor, because you may be having a reaction to the brown recluse spider's venom.

Step 3

Keep an eye on a bite that you suspect may be from a brown recluse spider. In some people, the bite heals quickly, in others, the bite continues to get worse. If it is a brown recluse spider bite, the red area may continue to spread. Spreading of the red area is not necessarily a cause for concern, but it does warrant that you continue to keep an eye on the bite to watch for further symptoms.

Step 4

Evaluate how you are feeling. People who have a reaction to the venom of a brown recluse may feel dizzy, nauseous or have muscle pain or the chills. These symptoms usually appear one to two days after the bite. If you have any of these symptoms, seek treatment from a doctor.

Step 5

Watch the bite for signs of infection and skin tissue death. If the skin turns black, the skin appears to be wasting away or if the blister turns into a large deep ulcer, go to a doctor. Some brown recluse bites cause necrosis (tissue death). Left untreated, necrosis is serious. In rare instances, tissue death is severe and can result in the loss of a large amount of skin and underlying tissues. Note: It is normal for the blister to pop and a small ulcer to form in its place. It is only if the ulcer is large, deep or spreading that there is a cause for concern. Also, an ulcer that will not heal is a cause for concern.

Tips & Warnings

 

Medical treatment for a brown recluse spider is antibiotics. In cases of serious bites where the bite does not heal and tissue death is spreading, surgery is performed.

 

Medical treatment for a brown recluse spider is antibiotics. In cases of serious bites where the bite does not heal and tissue death is spreading, surgery is performed.

 

Because spider bites and symptoms of spider bites can vary greatly, this article should not be considered an all inclusive list of possible outcomes. If you suspect that you have been bitten by a brown recluse spider, call a doctor to seek advice.

 

Because spider bites and symptoms of spider bites can vary greatly, this article should not be considered an all inclusive list of possible outcomes. If you suspect that you have been bitten by a brown recluse spider, call a doctor to seek advice.

 

Pasted from <http://www.trails.com/how_2149_identify-brown-recluse-bite.html>