You may not feel a bite by a brown recluse spider, but you could initially feel a sting. More symptoms show up within several hours. Calling a doctor is crucial because they can become severe.

Brown recluse spiders prefer warm climates and are usually found in the central and southern United States. They often live in dark, sheltered areas, such as piles of wood, leaves, or rocks. They may also live inside people’s homes or under their porches. Sometimes a brown recluse will even hide in shoes or under clothes that have been lying on the floor for a long time.

Brown recluse spiders have a dark, violin-shaped patch just behind their heads. This mark can be hard to see, so it’s easy to mistake a different kind of brown spider for a brown recluse.

You should immediately call your doctor or go to the emergency room if you believe a brown recluse spider has bitten you. Prompt treatment is especially important for children or elderly people because they often have more severe symptoms.

Brown recluse spiders aren’t aggressive spiders and will only bite if they are trapped against skin. They usually hide during the day and come out at night to hunt for insects.

Once spiders are inside a home or building, it’s almost impossible to get rid of them entirely. You can set out sticky traps and use repellents to help reduce the number of spiders. Also take these precautions to lower your chances of being bitten:

  • Clean up clutter in your yard and basement, and avoid stacking wood against the house. This can help remove the types of places where brown recluse spiders like to live.
  • Avoid leaving clothing on the ground. If you do, be sure to shake it out before putting it on.
  • Wear gloves when moving wood and rocks, especially if you live in an area where brown recluse spiders are common.
  • Be careful when taking things out of storage, as brown recluse spiders often live in cardboard boxes.
  • Check inside shoes before putting your foot in one.
  • Store tools and hand-held outdoor equipment in tightly sealed plastic bags to avoid spider encounters.

You usually don’t feel it when a brown recluse spider bites you. That means you might not even realize you’ve been bitten if you don’t actually see the spider on your skin. If you do feel it, the bite may sting at first.

Symptoms from the venom usually don’t develop for several hours. Then you may feel pain, burning, or itching around the bite site. The area may become red. A small white blister can also form at the site.

Additional symptoms you may develop soon after the bite include:

About 12 to 36 hours after the bite, a characteristic, unique pattern of discoloration can develop. The site of the bite may turn a deep purple or blue color and be surrounded by a whitish ring and a larger red area. There may also be a dark blister or ulcer by the bite. In some cases, the ulcer caused by the bite can persist and grow for weeks.

Go to the emergency room or call your doctor immediately if you think a brown recluse has bitten you. If possible, catch the spider in a jar and take it with you. This can help your doctor identify the spider and confirm the diagnosis. Often in the emergency department, a doctor will give you a tetanus booster.

On your way to the doctor’s office or emergency room, take these first aid steps:

  • Wash the bite wound with soap and water as soon as possible.
  • Elevate the area where the bite occurred.
  • Apply a cool compress or ice pack to the bite to help with swelling and pain — 10 minutes on, then 10 minutes off.

As scary as a brown recluse bite may sound, it usually isn’t dangerous. Most bites will heal on their own without complication.

Still, you should always get medical attention if you think you’ve been bitten by a brown recluse. That’s because in the unlikely chance that you do have a complication, it can be a serious condition. These include blood disorders, kidney failure, coma, or even death. Complications like these are more likely to happen in children and older adults.

There is no recommended antivenom (medicine that counteracts the poison in the bite, called venom) for brown recluse spiders. Most bites will respond to rest, ice, and elevation.

A number of other treatments and medications have been used in managing skin complications from a bite. In studies, however, none of these treatments have consistently shown to be reliable and effective. Those often used include:

  • colchicine (Colcrys, Mitagare), a medication used in treatment of gout
  • corticosteroids, drugs that relieve inflammation
  • dapsone, an antibiotic used in the treatment of Hansen’s disease (leprosy)
  • diphenhydramine (Benadryl), an antihistamine
  • hyperbaric oxygen
  • nitroglycerin, a heart medication
  • NSAIDs, such as ibuprofen (Advil)
  • pain relievers

Your doctor may also prescribe antibiotics if the wound from the bite becomes infected.

With proper medical attention, full recovery is likely. In most cases the bite will improve with rest, ice, and elevation. If more serious skin complications develop, it may take weeks for the bite wound and any ulcers or blisters to heal entirely.