Meet the Brown Recluse Spider
Photos & article by: Kevin Weiner
This is a female Brown Recluse (Loxosceles reclusa). They have a fiddle shape on their cephalothorax (front end) and six eyes situated in 3 pairs. They are medically significant to humans, but research shows that bites are rare due their design and behavior.
The orientation of the fangs along with their being fused give them little movement of the fangs compared to a lot of other spiders which makes it difficult for a bite to occur without being pressed into the skin by an external force.
A bite also cannot occur through clothing. It’s believed that most actual bites occur when they get trapped in clothing, shoes, or in bed. Now moving on to their behavior…they are called recluses for a reason.
They tend to keep to themselves in dark out of the way areas. As with any spider, when it comes to fight or flight, they choose flight. They instinctively know we can cause them harm and know better than to stand their ground.
Brown Recluse Bites
It is also believed that if the infection started as a bite, it would be much more likely to have been from certain insects.
It is also not possible, from a wound alone, to diagnose a Brown Recluse bite. Many infections/skin conditions can look like a Brown Recluse bite and, therefore, the spider has to be presented to a doctor along with the wound and that spider has to be identified (by an expert in spiders) as a Recluse in order for a confirmed diagnosis.
Otherwise it’s just guessing. Brown recluse bites can and do happen… it’s just not near as common as once believed.
Brown Recluse Spider Envenomations
Written by: Spencer Greene, MD (taken from Facebook)
We frequently receive questions about spider envenomations over at National Snakebite Support, which is surprising, considering the name “National Snakebite Support” seems pretty unambiguous. I feel bad ignoring these questions, because there is A LOT of ignorance out there, but we need to keep NSS focused on suspected venomous snakebites.
So, I have decided to make this post. Share it far and wide, especially with the people who insist they had a really bad spider bite and you know in your heart of hearts they had something other than a spider bite.
If I had a dollar for every time someone insisted he or she had experienced a Recluse spider bite, I could retire and afford to pay someone else to write this post. I estimate that for every 200 people who present to the emergency department alleging a “Brown Recluse spider bite,” maybe ONE actually has one.
Most of the time it’s a soft tissue infection. Let’s talk about how to distinguish one from the other. Well, technically it’s me telling y’all; this isn’t an actual conversation. Regardless…
Bites from the Recluse spiders, including, but not limited to, Loxosceles reclusa (aka the Brown Recluse), often go unnoticed initially. Sometimes there’s pain, but frequently the bite is not particularly uncomfortable.
Over the course of several hours and days, there’s a progression of the local findings. There will be erythema (redness) surrounding a white ring of ischemia (decreased blood flow) surrounding a central area where an ulcer and possibly an eschar develop.
After several days there may be some elevation along the margins, but in general there’s not significant swelling. There’s definitely no fluctuance or purulent drainage; these are suggestive of a soft tissue infection.
And, no, this infection isn’t due to a spider bite. You have one or the other. You’re not entitled to multiple diagnoses. It’s important to distinguish the two, because the treatment for a cutaneous abscess is incision, drainage, and antibiotics.
On the other hand, the overwhelming majority of recluse bites (anywhere from 85% to 97%, depending on the study) will recover on their own, and premature surgical intervention will actually impaired wound healing. There’s also no need for antibiotics following a recluse spider envenomation.
Death is fortunately really uncommon following Recluse bites, but when there is a death, it’s usually in a child, and it’s due to systemic loxoscelism, which takes one or more days to develop and is characterized by significant hemolysis (red blood cell destruction) which can result in severe anemia, renal (kidney) failure, and cardiovascular collapse.
For recluse spider envenomations, we treat the local damage by leaving it the hell alone. Keep it clean. Don’t cut into it. We don’t use dapsone anymore. These don’t require antibiotics. We don’t use nitroglycerin. We don’t use corticosteroids. The benefits of hyperbaric oxygen are unclear. As I mentioned earlier, almost all of these will eventually heal on their own, so we definitely want to avoid premature surgical intervention. A small percentage will require skin grafts, but these should not even be considered for at least six weeks after the bite.