How to Tell If You Have a Brown Recluse Spider Bite—And How to Treat It

Brown recluse spiders are one of the only spiders that are able to bite humans. And though you may not immediately feel the a bite from a brown recluse, it often progresses to an extremely painful bite that gets progressively worse and more painful as the venom enters your system and your tissues.

In fact, the bite will eventually develop into an ulcer that is black with a crust. In some cases, it can even lead to a serious infection.

Here is what you need to know about brown recluse bites, their symptoms, and the treatment options.

What is a Brown Recluse Spider?

The brown recluse spider, or Loxosceles reclusa, is a dark brown spider with a violin shape on its back. This spider—sometimes called the fiddleback spider or violin spider—is found predominantly in the Midwest and Southeast United States.

Known for its reclusive or secretive behaviors, this spider is about 1/4-inch to 1/2-inch long, with female spiders being larger than males. And while most spiders have eight eyes, the brown recluse only has six eyes that appear in three pairs in a semicircle pattern.

The brown recluse, which is a venomous spider, prefers to live in warm, dry, and dark environments such as inside of shoes in a closet, behind woodpiles, in boxes in attics, or between folded garments in a basement.

While this spider is one of only a few spiders that can bite humans, it usually does so when it feels trapped, such as when a hand reaches into a box or a foot slides into a shoe. It's also a long-living spider and has an average lifespan of about two to four years.

What Happens if a Brown Recluse Spider Bites You?

While you may not feel the bite from a brown recluse spider when it first occurs, it can sometimes produce a tingling sensation followed by intense pain. Other times, this reaction is delayed for six to eight hours. As the spider’s venom penetrates your skin and tissues, it causes injury and death (necrosis) to your surrounding tissues.

When you are first bitten, the location of the bite may appear look like any other insect bite, appearing red and inflamed. It also can be a little itchy. As days pass, though, more severe symptoms may develop as the venom spreads and destroys the surrounding tissues. The wound, which can start to look like a blister, may get larger and more painful.

Eventually, an ulcer may develop that is black with a crust. That crust will fall off in about 10 to 14 days. If the venom penetrates deeper into your tissues, it also can affect your fat and muscles, progressing to an infection and slowing the healing process. Though rare, the infection also can spread to the rest of your body and possibly become life-threatening. Once healed, though, the bite leaves a crater-like scar, even after it has healed completely.

It is challenging for healthcare professionals to diagnose a brown recluse bite unless you felt the bite and identified the spider from the start. There are a number of conditions that have the same symptoms of a brown recluse bite like a bacterial, viral, or fungal infection. Other insect bites and some medical conditions that impact blood circulation also can have the same symptoms.

What to Do if a Brown Recluse Spider Bites You

If you are bitten by a brown recluse spider, you should wash the area with soap and water and contact Poison Control (1-800-222-1222). You also can try using an ice pack to lessen the inflammation. Keeping the area cool helps reduce tissue damage. It also may reduce any burning sensation and pain you are experiencing. Applying an antibiotic ointment can help prevent infection.

You also should:

• Elevate the area where you were bitten above your heart.
• Refrain from touching or scratching the bite.
• Apply a fresh bandage to the bite area.
• Consider taking an antihistamine to relieve itching.
• Use non-steroidal anti-inflammatory (NSAIDs) drugs to manage pain.
• See a healthcare provider for further evaluation.
  

If you can find the spider—even if it is crushed—you should put it in a container and take it with you for evaluation. Knowing whether or not you were bitten by a brown recluse will help the healthcare provider know how to treat you.

When to Contact a Healthcare Provider

A brown recluse spider bite is extremely toxic and needs treatment that will accelerate recovery and minimize tissue loss. If you suspect that you have been bitten by a brown recluse, you should wash area with soap and water and call Poison Control at 1-800-222-1222. Because the brown recluse's venom is a poison, these specialists can advise you on what to do as well as communicate with the emergency room staff if you are directed there.

If you are unclear what type of insect bite you have, you should still be evaluated by a healthcare provider. Get medical care right away or go to the emergency room if you experience any of the following symptoms:

• Experience signs of an allergic reaction like difficulty breathing, throat closing, swelling
• Develop any kind of rash after a bite
• Have increasing redness, pain, swelling, warmth, pus, or other signs of infection
• Experience a racing heartbeat that lasts longer than a few minutes
• Feel nauseous or vomit
• Have a fever or experience chills
  
• Get a headache
• Experience chest pain

How Are Brown Recluse Spider Bites Diagnosed?

It is very hard for a healthcare provider to diagnose a brown recluse bite. Not only do the symptoms appear similar to a number of other conditions, but it can hard to determine what type of insect caused your reaction—especially since there are no lab test to confirm the diagnosis.

That said, healthcare providers often use the mnemonic "NOT RECLUSE" to help exclude a brown recluse spider bite. Here is a closer look at what that looks like:

• N (numerous): Because you usually only have one lesion from a brown recluse bite, if you have more than one lesion or bite, it is unlikely you were bitten by a brown recluse.
• O (occurrence): A healthcare provider will ask if you know how the bite occurred. A brown recluse bite usually occurs when they are disturbed like in an attic, basement, or dark box.
• T (timing): Most brown recluse bites occur between April and October.
• R (red center): Brown recluse bites usually have a pale central area.
• E (elevated): A bite from a brown recluse spider will be flat. If the area is raised more than 1 centimeter, it is likely not a brown recluse bite.
• C (chronic): Bites from a brown recluse usually heal within three months and are not chronic.
• L (large): If your bite is large, or greater than 10 centimeters, it is likely not a brown recluse bite.
• U (ulcerates early): It can take seven to 14 days for a brown recluse bite to ulcerate (or for the ulcer to form). If you get an ulcer sooner, it is likely not from a brown recluse
• S (swollen): Typically, a bite from a brown recluse does not swell unless it is on the face or the feet.
• E (exudative): Brown recluse spider bites do not cause exudative lesions.

How Are Brown Recluse Spider Bites Treated?

One of the first steps a healthcare provider may take when treating a brown recluse bite is to ensure your tetanus immunizations are up to date, especially since there is no antidote for a brown recluse spider bite. If you are unsure of your last tetanus shot, then you will likely be given a booster. Meanwhile, your pain can be treated with NSAIDs, but some people may have such severe pain that they need a short course of opioids.

Typically, antibiotics are only used if you have an infection like cellulitis (a bacterial skin infection) while steroids also may be prescribed—especially since they can decrease hemolysis (or the destruction of red blood cells). Surgery is sometimes used but not until the condition has advanced. In fact, early surgical treatment is not recommended.

How to Prevent Brown Recluse Spider Bites

Preventing brown recluse spider bites begins with knowing where they like to live and using caution in those areas as well as addressing any infestations you come across. For instance, if you notice webs in and around your home, contact a licensed pest professional to inspect and treat the problem. Here are some other things you can do:

• Inspect the outside of your home for small openings and holes (like around utility pipes).
• Seal the openings with silicone caulk to prevent spiders from entering your home.
• Stack firewood 20 feet away from your home and at least 5 inches off the ground to deter spiders from hiding in the wood.
• Wear gloves when moving the wood and inspect it before bringing it inside.
• Avoid leaving clothes on the floor or shake them out before wearing them.
• Shake out shoes before putting them on, especially if they have been stored in the basement, garage, or another dark area.
• Keep seldom used items like boots, baseball mitts, skates, gardening gloves, and more in tightly sealed bags or boxes so spiders will not hide in them.
• Warn the spiders you are coming by stomping or making a lot of noise in attics and basements.

A Quick Review

A brown recluse is a spider with a violin shape on its back. This type of spider is reclusive and likes to hide in shoes, attics, and around wood piles where it is warm, dark, and dry. Although you may not feel a brown recluse bite right away, it can quickly progress to an ulcerative area that contains a black dot and crusty area. As the venom from the spider kills your tissue, the blackness may spread and it can become infected.

Find treatment right away if you are bitten by a brown recluse. You can start by calling Poison Control and keep the spider in a container, even if it is crushed so it can be evaluated. Typically, it can take about three months for your bite to heal completely, but if you do not seem to be getting better, contact a healthcare provider or go to the emergency room if you have a fever, chills, or extreme pain in the area.