Sneaky SF Dude
15 June 2003, 12:51
My offering for the first thread for Medical Question of the Week. This is one of my favorites from the Q Course.
The Brown Recluse spider, Loxosceles reclusus, living up to its name, is naturally nonaggressive toward humans and prefers to live in undisturbed areas. The brown recluse is about 1/4 to 1/2 inches (6-12 mm) in body length and have a leg span of over 1 inch (25 mm). Most adults are about the size of a United States dime to a U.S. quarter with legs extended. The spider can tolerate temperatures from 32 degrees Fahrenheit (0 degrees
Celsius) to over 100 degrees Fahrenheit (38 degrees Celsius). Coloration ranges from tan to dark brown, with the abdomen often darker than the rest of the body. Characteristic violin-shaped markings on their backs have led brown recluses to also be known as fiddleback spiders. The darker violin-shaped marking can be seen on top of the leg-bearing section of the
body. The neck of the violin "silhouette" points towards the rear (abdomen) of the spider. Brown recluse spiders also have six eyes, rather than eight for most other spiders. They are most active at night from spring to fall.
The brown recluse roams at night seeking its prey. During the day, it hides in dark niches and corners, where it may spin a poorly organized, irregular web. It is shy and will try to run from a threatening situation but will bite if cornered. People are sometimes bitten while putting on a shoe or piece of clothing which a spider has selected for its daytime hiding place. People are also bitten while they are asleep because they roll onto
a brown recluse spider in the bed.
The brown recluse may be found living indoors or outdoors. Thorough inspection of cracks, corners, and other dark, undisturbed areas with a bright flashlight will help determine the location and extent of infestation. Indoors, pay particular attention to basements, attics, crawl spaces, closets, under/behind beds and furniture, inside shoes, boxes of
stored items, and between hanging clothing. Brown recluse spiders also may be found living above suspended ceilings, behind baseboards, and inside ductwork or registers.
Medical Significance
The bite from a brown recluse spider rarely causes death. The bite of the brown recluse is usually painless. Over the next 3 to 8 hours, the poison begins to kill the tissues around the bite, which is very painful. The area around the bite site may become red, swollen, and tender, developing into an ulcerous sore from 1 to 10 inches in diameter. This reaction gives a whitish appearance immediately surrounding the bite with a large reddened area around the white area. Aside from the skin problems, the poison and skin breakdown can cause chills, fever, nausea, and other flu-like symptoms.
Symptoms of a brown recluse bite include a rash, fever, chills, nausea, vomiting, and joint pain. In severe case, patients may also have renal failure, seizures, or coma. Healing often requires a month or longer, and the victim may be left with a deep scar. The destruction of the skin surrounding the bite can be quite significant occasionally requiring skin grafts. Prompt medical attention can reduce the extent of ulceration and alleviate other complications that may develop. Not all brown recluse bites
result in ulcerations or scarring.
Spider bites are difficult to diagnose, even by physicians. If bitten, it is best to clean the bite with soap and water and then place an ice pack over the wound. If possible, capture the spider (safely) so that it can be positively identified. Then, seek medical assistance immediately.
Unfortunately, there isn't a tremendous amount that can be done to neutralize the poison. Medications to decrease the body's inflammatory reaction to the poison are the primary methods of treatment. Ultimately the best "treatment" for brown recluse spider bites is prevention and control.
Control
Eliminating an infestation of brown recluse spiders involves two basic principles:
*Altering the environment in and around a building to make it less
attractive to spiders; and
*Finding and destroying as many spiders as possible.
To Avoid being bitten:
*Shake clothing, blankets, and shoes that have been on the floor or not been worn in a while.
*Wear long sleeves and gloves when moving boxes or working in storage areas.
*Wash or check bed linens in beds that have not been slept in for a while.
The following measures can be used to control all spiders, including the brown recluse.
*Routine, thorough house cleaning is the best way to eliminate spiders and discourage their return. A vacuum cleaner or broom effectively removes spiders, webs, and egg sacs.
*Spiders prefer quiet, undisturbed areas such as closets, garages, basements, and attics. Reducing clutter in these areas makes them less attractive to spiders. Try not to make piles of objects in the closet, attics, and basements that are not cleaned regularly.
*Large numbers of spiders often congregate outdoors around the perimeter of structures. Moving firewood, building materials, and debris away from the foundation indoors can reduce migration. Shrubs, vines and tree limbs should be clipped back from the side of buildings. Removal of unnecessary clutter is especially helpful in making areas unattractive to these pests.
*Install tight-fitting window screens and door sweeps to exclude spiders and other insects. Inspect and clean behind outdoor window shutters.
*Consider installing yellow or sodium vapor light bulbs at outside
entrances. These lights are less attractive than mercury vapor,
fluorescent, or incandescent bulbs to night-flying insects, which in turn, attract spiders.
*Use glueboards or sticky traps to detect infestations. These devices, designed to capture mice and cockroaches, can be purchased at grocery or hardware stores. Place flush along walls and in corners. Glueboards and sticky traps are useful monitoring tools and will also capture large numbers
of spiders.
The Brown Recluse spider, Loxosceles reclusus, living up to its name, is naturally nonaggressive toward humans and prefers to live in undisturbed areas. The brown recluse is about 1/4 to 1/2 inches (6-12 mm) in body length and have a leg span of over 1 inch (25 mm). Most adults are about the size of a United States dime to a U.S. quarter with legs extended. The spider can tolerate temperatures from 32 degrees Fahrenheit (0 degrees
Celsius) to over 100 degrees Fahrenheit (38 degrees Celsius). Coloration ranges from tan to dark brown, with the abdomen often darker than the rest of the body. Characteristic violin-shaped markings on their backs have led brown recluses to also be known as fiddleback spiders. The darker violin-shaped marking can be seen on top of the leg-bearing section of the
body. The neck of the violin "silhouette" points towards the rear (abdomen) of the spider. Brown recluse spiders also have six eyes, rather than eight for most other spiders. They are most active at night from spring to fall.
The brown recluse roams at night seeking its prey. During the day, it hides in dark niches and corners, where it may spin a poorly organized, irregular web. It is shy and will try to run from a threatening situation but will bite if cornered. People are sometimes bitten while putting on a shoe or piece of clothing which a spider has selected for its daytime hiding place. People are also bitten while they are asleep because they roll onto
a brown recluse spider in the bed.
The brown recluse may be found living indoors or outdoors. Thorough inspection of cracks, corners, and other dark, undisturbed areas with a bright flashlight will help determine the location and extent of infestation. Indoors, pay particular attention to basements, attics, crawl spaces, closets, under/behind beds and furniture, inside shoes, boxes of
stored items, and between hanging clothing. Brown recluse spiders also may be found living above suspended ceilings, behind baseboards, and inside ductwork or registers.
Medical Significance
The bite from a brown recluse spider rarely causes death. The bite of the brown recluse is usually painless. Over the next 3 to 8 hours, the poison begins to kill the tissues around the bite, which is very painful. The area around the bite site may become red, swollen, and tender, developing into an ulcerous sore from 1 to 10 inches in diameter. This reaction gives a whitish appearance immediately surrounding the bite with a large reddened area around the white area. Aside from the skin problems, the poison and skin breakdown can cause chills, fever, nausea, and other flu-like symptoms.
Symptoms of a brown recluse bite include a rash, fever, chills, nausea, vomiting, and joint pain. In severe case, patients may also have renal failure, seizures, or coma. Healing often requires a month or longer, and the victim may be left with a deep scar. The destruction of the skin surrounding the bite can be quite significant occasionally requiring skin grafts. Prompt medical attention can reduce the extent of ulceration and alleviate other complications that may develop. Not all brown recluse bites
result in ulcerations or scarring.
Spider bites are difficult to diagnose, even by physicians. If bitten, it is best to clean the bite with soap and water and then place an ice pack over the wound. If possible, capture the spider (safely) so that it can be positively identified. Then, seek medical assistance immediately.
Unfortunately, there isn't a tremendous amount that can be done to neutralize the poison. Medications to decrease the body's inflammatory reaction to the poison are the primary methods of treatment. Ultimately the best "treatment" for brown recluse spider bites is prevention and control.
Control
Eliminating an infestation of brown recluse spiders involves two basic principles:
*Altering the environment in and around a building to make it less
attractive to spiders; and
*Finding and destroying as many spiders as possible.
To Avoid being bitten:
*Shake clothing, blankets, and shoes that have been on the floor or not been worn in a while.
*Wear long sleeves and gloves when moving boxes or working in storage areas.
*Wash or check bed linens in beds that have not been slept in for a while.
The following measures can be used to control all spiders, including the brown recluse.
*Routine, thorough house cleaning is the best way to eliminate spiders and discourage their return. A vacuum cleaner or broom effectively removes spiders, webs, and egg sacs.
*Spiders prefer quiet, undisturbed areas such as closets, garages, basements, and attics. Reducing clutter in these areas makes them less attractive to spiders. Try not to make piles of objects in the closet, attics, and basements that are not cleaned regularly.
*Large numbers of spiders often congregate outdoors around the perimeter of structures. Moving firewood, building materials, and debris away from the foundation indoors can reduce migration. Shrubs, vines and tree limbs should be clipped back from the side of buildings. Removal of unnecessary clutter is especially helpful in making areas unattractive to these pests.
*Install tight-fitting window screens and door sweeps to exclude spiders and other insects. Inspect and clean behind outdoor window shutters.
*Consider installing yellow or sodium vapor light bulbs at outside
entrances. These lights are less attractive than mercury vapor,
fluorescent, or incandescent bulbs to night-flying insects, which in turn, attract spiders.
*Use glueboards or sticky traps to detect infestations. These devices, designed to capture mice and cockroaches, can be purchased at grocery or hardware stores. Place flush along walls and in corners. Glueboards and sticky traps are useful monitoring tools and will also capture large numbers
of spiders.