What is brown recluse spider bite?

Brown recluse, violin, or fiddleback (Loxosceles) spiders are about 0.5 in. (1.3 cm) long with a dark violin-shaped mark on the combined head and midsection (cephalothorax). They are found most often 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:

• Reddened skin that may be followed by a blister that forms at the bite site.
• Mild to intense pain and itching for 2 to 8 hours following the bite.
• An open sore (ulcer) with a breakdown of tissue (necrosis) that develops a week or more following the bite. This may take months to heal.

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:

• Fever and chills.
• Skin rash all over the body with many tiny, flat purple and red spots.
• Nausea or vomiting.
• Joint pain.

A brown recluse spider bite is diagnosed through a physical examination 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:

• Do not develop open sores, treatment includes applying a cold compress, elevating the bite area, and avoiding moving the bite area.
• Cause an open sore (ulcer) and dead skin (necrosis), treatment includes removing the dead skin from the sore. This may involve follow-up and replacing the dead skin with new skin (skin grafts).

Hyperbaric oxygen therapy may also be used for tissue damage from a spider bite.

Medicines that may be used include:

• Pain medicine, such as acetaminophen (Tylenol) or nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs include naproxen (Aleve) and ibuprofen (Advil, Motrin). Be safe with medicines. Read and follow all instructions on the label.
  Do not give aspirin to anyone younger than 20 because of the risk of Reye syndrome.
• Antihistamines to help relieve itching.
• Antibiotics, if an infection is present.

Medicine to counteract brown recluse spider venom is not available in the United States or Canada.

• If the doctor gave you a prescription medicine for pain, take it as prescribed.
• If your doctor prescribed antibiotics, take them as directed. Do not stop taking them just because you feel better. You need to take the full course of antibiotics.
• Take an over-the-counter antihistamine, such as fexofenadine (Allegra) or loratadine (Claritin), to calm the itching and reduce the swelling. Read and follow all instructions on the label.
• Put ice or a cold pack on the bite for 10 to 20 minutes at a time. Put a thin cloth between the ice and your skin.
• If your doctor told you how to care for your wound, follow your doctor's instructions. If you did not get instructions, follow this general advice:
  • Wash the bite area with clean water 2 times a day. Don't use hydrogen peroxide or alcohol, which can slow healing.
  • You may cover the bite with a thin layer of petroleum jelly, such as Vaseline, and a nonstick bandage.
  • Apply more petroleum jelly and replace the bandage as needed.