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Brown recluse , violin, or fiddleback (Loxosceles) spiders are about 1.3 cm (0.5 in.) long with a dark violin-shaped mark on the combined head and midsection (cephalothorax). These spiders are not native to Alberta, so the risk of encountering them is very low. Most often they are found in the south-central part of the United States and live in hot, dry, abandoned areas, such as wood or rock piles.
A brown recluse bite can be serious and may require immediate medical care.
Brown recluse spider bites don't always hurt right away. In fact, you may not know that you have been bitten until other symptoms appear. Symptoms of a brown recluse spider bite include:
Some people have a severe, systemic (whole-body) reaction to brown recluse spider bites, including the rapid destruction of red blood cells and anemia (hemolytic anemia). Signs and symptoms include:
Try to stay relaxed.
Apply a cool, wet cloth to the bite, or cover the bite with a cloth and apply an ice bag.
A tourniquet may cause more harm than benefit.
Try to positively identify the spider, or try to take a picture of it.
A brown recluse bite can be serious and may require immediate medical care if you have severe symptoms throughout your body. Call your doctor if an open sore and necrosis develop. Necrosis is black, dead tissue.
A brown recluse spider bite is diagnosed through a physical exam and questions about the bite. You should be prepared to describe the spider, where and when the bite took place, and what you were doing at the time. (If you are able to safely capture and transport the spider, bring it with you to show your doctor.) Your doctor will ask what your main symptoms are, when they began, and how they have developed, progressed, or changed since the bite.
Treatment depends on how severe the bite is. For bites that:
Hyperbaric oxygen therapy may also be used for tissue damage from a spider bite.
Medicines that may be used include:
Do not give aspirin to anyone younger than 18 because of the risk of Reye syndrome.
Medicine to counteract brown recluse spider venom is not available in Canada or the United States.
Adaptation Date: 8/18/2022
Adapted By: Alberta Health Services
Adaptation Reviewed By: Alberta Health Services
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