Spider Bite Pictures of Brown Recluse, Black Widow, and More

It's easy to look at pictures of red, bumpy lesions on the internet—that other people have tagged as spider bites—and think, "that's what I have!"

The problem is that many images are misidentified as spider bites by websites, patients, and even doctors. They might be from spiders, but they can also be from other types of bugs or infections. The pictures below show different types of lesions that are often identified as spider bites. Each one is discussed on how it could—or could not—be from a spider.

There are only two medically significant spider species in North America: the black widow and the brown recluse. Black widow bites, for example, are very difficult to diagnose by looking at the site of the bite, unless it includes fang marks (see below). It's easier to say definitively when a lesion is not a brown recluse bite than when it is.

Bottom line: Without catching a spider in the act, there might not be an accurate diagnosis. Nevertheless, whether it's a spider or another kind of bug bite, treatment is generally the same.

Expanding Lesions

An expanding lesion, like the one in the picture, is common in brown recluse bites, but there are many other possibilities to consider. Some skin infections can lead to lesions like this. The only way to tell for sure is to have it evaluated by a medical professional.

Bullseyes

bullseye from spider bite — Jake from Atlanta

One of the things that set bites apart—whether from spiders or other bugs— from infections is the "bullseye" pattern of discoloration. It shows up as concentric rings of discoloration.

It's common in tick bites, especially those that later turn into Lyme disease, and can also be present for spiders.

Ticks, scorpions, and spiders are all arachnids.

Fang Marks

Black widows have fangs, almost like miniature snakes. Soon after a black widow spider bites you—before any reaction starts—you might be able to see two small holes like those in this image.

Black widow venom can cause muscle spasms and heart disturbances, but if you have a black widow spider bite, rest assured that they are rarely fatal. The most common symptoms after a bite (besides the pain of the bite itself) are:

Abdominal pain
Muscle cramps/soreness
Soreness and redness around the bite
Irritability/agitation

High blood pressure is also common from black widow spider bites, although it rarely causes any problems for the patient. Most of the symptoms are treated individually. An antivenin (spider poison antidote) is available for black widow spider venom, but it's not really necessary for most patients.

Classic Recluse Spider Bite

Brown recluse bites can go unnoticed, or they can lead to severe pain 2 to 8 hours after the bite. In some cases, patients report feeling a "pinprick" at the site of the spider bite. In true cases of loxoscelism (medical terminology for the condition caused by brown recluse bites), skin tissue that develops could take several months to fully heal and the scars may remain. Generally, brown recluse bites are much less likely to cause significant injury than black widows.

Your Spider Bite Might Not Be a Bite at All

It's nearly impossible to say for sure if a spider bite comes from a brown recluse without the use of a lab test. However, there are some telltale signs that can be used to rule out the possibility of a brown recluse bite.

NOT RECLUSE is an acronym for the signs that a wound or lesion is not caused by a brown recluse bite. It stands for:

Numerous
Occurrence
Timing
Red center
Chronic
Large
Ulcerates too early
Swollen
Exudes moisture

The presence of any of these is an indicator that the wound isn't from a brown recluse. The presence of two or more of these signs almost guarantees that it's not. Let's take a look at each one.

Lots of Lesions Are Not Spider Bites

Multiple bites are not typically from spiders, especially not a brown recluse or black widow. In cases with so many bites, consider bugs that travel in groups, like mosquitoes, bed bugs, or chiggers, for example.

How It Happens Makes a Difference

In order to be a brown recluse bite, the way the bite happened is very important to the story. If the bite occurred because the patient disturbed a spider by moving old boxes in the attic, that's much more likely than getting a bite in the yard.

Recluse spiders have that name for a reason; they don't like crowds. They hide in really out of the way, dark places. Bad luck in the backyard, for example, could be due to poison ivy or spiders. It could also be a result of chiggers, which like to get into boots and socks to bite their prey.

When it happens matters, too. If a bite doesn't happen from April to October, the chance that it's from a brown recluse are slim to none. Brown recluses are notoriously inactive during the rest of the year.

Red, Inflamed Centers Point to Infection

A red, inflamed center is not an indicator of a brown recluse bite. Loxoscelism (brown recluse envenomation) is known for having a dark, flat center.

A swollen, hot area can easily be a staph infection. There is a possibility that it's a bug bite, but skin infections are even more likely. Lest you think that staph infections can be the result of a spider bite, it's probably not the case. At least one study found that spiders do not regularly carry bacterial infections.

Long Time to Heal

chronic bites help identify non-recluse spiders — Angela Phillips

If it takes a really long time for the lesion to heal, it might not be a brown recluse bite. They've got a reputation for lasting a while, but most brown recluse bites heal within three weeks and the biggest of them heal within three months.

A line drawn around the lesion, as shown in the picture, is a common method for keeping track of an expanding rash or area of swelling. Be sure to note the time and date when a line is drawn to know how fast the lesion expands.

Massive Sores

Brown recluse bites are known for having necrosis (dead tissue) in the center of the lesion. However, the necrosis is not going to be bigger than 10 centimeters across (four inches).

A lot of infected sores are identified—even diagnosed—as spider bites. In truth, unless you have a spider to identify as the culprit, the odds are against a spider bite. It's much more likely that a non-spider bug did the biting in this case.

If the lesion grows or continues to get worse over a 24 hour period, it's worth taking a trip to see the doctor. If not, it's probably fine just to keep it clean and keep an eye on it.

Ulceration

A brown recluse bite will eventually break the skin (ulcerate), but if it happens before the week is out, it's probably not a brown recluse. Sometimes, it's not really obvious that the lesion ulcerated, other than the fact that it develops a crust.

So, if it's bleeding or crusty and it hasn't been a week, it's probably something other than a brown recluse bite.

Swelling

Swollen eye from brown recluse spider bite — CDC

Swelling typically indicates something other than a brown recluse bite. Below the neck, brown recluse bites do not result in significant swelling. Above the neck is a different story. Bites on the eyelids and other very soft tissues of the face often swell after a recluse bite.

Any bug bite can lead to swelling from allergic reaction or envenomation.