CPR First Aid

How Dangerous Is a Brown Recluse Spider Bite

How Dangerous Is a Brown Recluse Spider Bite?

Another day, another spider steps into the spotlight. With all the possible spider species in Australia, it is not uncommon to see a new species of spider every so often. Apart from the very dangerous funnel web and red back spiders, the brown recluse spider is yet another notable arachnid to take note of. 

Other than learning more about it, we are here to find out whether this spider’s bite is dangerous to humans. 

Let’s dive in and see how dangerous the bite from this spider really is. 

Leading Them Out of Reclusion

Before we get to the bite, as always, let’s find out more about this type of spider. This is our opportunity to lead it out of reclusion and bring its physical appearance, habitat, and many other characteristics into the light.

Physical Appearance

Appearance and Size

The size of this spider ranges from small to medium-sized. It has a dark brown, violin-shaped marking on its dorsal side (the back). This marking is why it is also called the fiddleback spider or the violin spider. The body of an adult is about 6 to 20 mm long with a leg span of up to 50 mm.


Its cephalothorax (the fused head and thorax) and legs are a uniform light brown to dark reddish-brown colour. There are no stripes or other markings on its body. The abdomen is slightly lighter in colour than the cephalothorax and has very fine hairs.


They have six eyes arranged in three pairs. Most spiders have eight eyes arranged in two pairs. One pair of eyes is located in the middle of the forehead, and the other two pairs are located on either side of the head. All of the eyes are the same size and shape.


This spider is found throughout much of the southern and central United States. It is most common in the Midwest and southeastern states. It is also found in parts of Central America, South America, and Africa. As the name suggests, they prefer to live in dark, sheltered places such as:

  • In woodpiles
  • Under stones
  • In debris
  • In cluttered storage areas

The hot weather has now driven these spiders into people’s homes. It can also be found indoors in basements, attics, crawl spaces, and closets. Outdoors, it is often found around foundations or under porches.

Primary Attractor

The primary attractor for this spider is insects. It will also eat other spiders and small animals if it can catch them. The diet of a brown recluse consists mostly of crickets, roaches, sowbugs, and mealworms.

It is not a social spider. It does not build webs to trap prey. Instead, it stalks its prey and then grabs it with its front legs. It will also eat dead insects.

Nighttime Creatures

This arachnid is a nocturnal creature and is most active at night. It comes out at night to hunt for food. If it is disturbed, it will quickly retreat to its hiding place.

During the day, it hides in dark places such as under rocks, debris, or similar hiding spots around the house. They use this time for webbing that they use to create egg sacs.

The Bite of the Brown Recluse Spider

Now that we know more about what the recluse looks like, where it lives, and what it eats, let’s get to the spider bite. We want to know whether the bite is dangerous to humans and what kind of symptoms occur from it.

Is the Bite Dangerous?

The short answer is equal parts yes and no. The recluse is a very venomous spider. Its venom rivals that of rattlesnakes. Fortunately, it is only capable of offloading a small amount of venom that is oftentimes not enough to kill a person.

While they are generally not aggressive, they will bite if it feels threatened. It will also bite if it is accidentally crushed or touched. The brown recluse will usually only bite humans if there is contact with the spider itself.

Most times, their bites will heal themselves. However, there are some cases where their bite results in the death of skin cells, nerves, and blood cells.

What Happens After a Bite?

The symptoms of a bite depending on how much venom was injected into the person and how sensitive they are to the venom. In most cases, symptoms develop within 2 to 8 hours after the bite occurs.

In some cases, there may be no symptoms at all. In other cases, the following symptoms may occur:

  • Intense pain
  • Nausea
  • Vomiting
  • Fever
  • Body aches
  • Rash
  • Itching
  • Blistering

As always, people can be allergic to the venom within a spider. This will trigger anaphylaxis which leads to a whole new set of problems.


The venom from this spider contains a protein that can kill tissue and cause necrosis (the death of cells). This can lead to the development of a lesion at the bite site. The lesion will start out as a small red bump that gradually gets larger.

In some cases, the lesion can become as large as 10 cm in diameter. Lesions usually take 2 to 3 weeks to heal. If left unchecked, the necrosis can spread. A surgeon will need to remove and repair these dead tissues. In some cases, skin grafts may become necessary.

In severe but rare cases, the venom from the recluse can cause:

  • Kidney failure
  • Liver damage
  • Muscle damage
  • Gangrene
  • Coma
  • Death

Treatment for a Recluse Bite

If you believe that you have been bitten by a brown recluse, it is important to seek medical treatment immediately. Try to capture the spider so the doctor can use it to determine the best course of treatment.

After being bitten, clean the wound with soap and water. Apply an ice pack to the area to reduce swelling. 

Do not attempt to remove the venom yourself. This can cause more damage. Venom removal kits are also not effective.

Your doctor will likely give you a tetanus booster if you have not had one in the past 5 years. If the bite is more severe, you may need to be hospitalised. You may receive antivenom, pain medication, IV fluids, and more.

Prevention is the Best Medicine

The best way to avoid being bitten is to take precautions to avoid contact with them.

First, inspect your clothing for spiders before getting dressed. Wear long-sleeved shirts and long pants if you know there are certain spiders in an area. Tuck your shirt into your pants and your pants into your socks and wear gloves.

In addition, make sure to shake out all clothing, towels, and bedding before use.

If you believe there is an infestation in your home, contact a professional pest control company. Do not attempt to remove them yourself as this can be dangerous.

Caution and Vigilance

While not immediately fatal, the bite from a brown recluse spider is capable of imbuing necrosis which kills tissues and cells. If left unchecked, the complications introduced could lead to life-long conditions and even death. 

Caution and vigilance are the best elixirs towards any spider, including this one. If you add the right first aid skills and knowledge, dangerous spiders can be easily handled. Not only will it help you with handling spider bites, but it will also come in handy for many other medical emergencies. 

Learn more about first aid with CPR First Aid’s Liverpool course today. 

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