How to recognize and treat a spider bite
Spider bite (HANDOUT / June 19, 2012)
A: Usually a person won't notice a spider bite until hours later. It can take that long for enough irritation from the bite to create discomfort.
Most spider bites are solitary (not a cluster of bites). The bite appears as a small, pink, raised bump on the skin. It's not very obvious.
Most spider bites require little treatment. They can be managed without visiting your doctor.
Wash the bite area with soap and water. Apply ice to reduce any swelling. Make sure you've had a tetanus booster within five years prior to the bite. If you haven't had a booster, tell your doctor you need one.
Several spiders can cause a more significant skin or body reaction.
--Black widow spider bites are uncommon in the United States.
--Funnel web spiders (known as "Hobo spiders") are found in Washington, Oregon, Wyoming, Idaho, and Northwestern Canada.
--Brown recluse spiders are commonly found in Missouri, Kansas, Arkansas, Louisiana, Texas, and Oklahoma.
Bites by hobo spiders and brown recluse spiders can deposit enough venom to break down the skin around the bite. This can prevent effective circulation to the healing area, rupture red blood cells, and trigger an allergic reaction.
Most of the time, symptoms from these venomous spider bites are limited to pain and skin changes right around the site of the bite.
Typically, the area around the bite will first appear very pale and then become red and swollen. After the first day, a bad bite can develop an open sore (an ulcer). Any dead skin around the bite can turn gray, black or blistered.
See a doctor if you think you've been bitten by a hobo spider or brown recluse and you have a reaction to the bite that's larger than the size of a quarter. Corticosteroid medicines or a medicine called "dapsone" may lessen the severity of the reaction. For skin reactions that include an ulcer, a doctor should supervise your care of the wound.
(Mary Pickett, M.D., is an Associate professor at Oregon Health and Science University where she's a primary care doctor for adults. She is a Lecturer for Harvard Medical School and a Senior Medical Editor for Harvard Health Publications.)
(For additional consumer health information, please visit www.health.harvard.edu.)
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