Spider Bite Pictures

You've likely found your way to this article because you or someone you're caring for has been bitten by an insect and you're wondering if what you're looking at is a spider bite. Photos of spider bites can be helpful in determining the culprit, but bites from other insects can look quite similar as well.

This article provides photos of different types of skin lesions and discusses whether or not they could be from a spider bite. That said, unless you actually catch a spider in the act, the only true way to determine whether you've been bitten by a spider is to be evaluated by a healthcare provider.

The good news is that though more than 50 spiders in the United States have venom, their bites are not serious and only cause minor pain or redness. Only two are poisonous to humans: the black widow and the brown recluse.

Signs of a Possible Spider Bite

The following are signs that you may have been bit by a spider.

Expanding Lesions

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A lesion that grows, expands, or spreads could have more than one cause, including a bite from a spider. Though this type of lesion is common in brown recluse bites, it may also be a sign of another skin infection, such as impetigo.

If you are unsure whether the lesion is growing, draw a line around it. This will help you keep track of whether or not the rash or area of swelling is expanding. Be sure to note the time and date when a line is drawn so you can tell how fast the lesion expands.

Bullseye Rash

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A bullseye rash—known as erythema migrans—can be sign of a bite from a type of bug called an arthropod. Spiders and ticks are types of arthropods.

Bullseye rashes are most common in tick bites that result in Lyme disease, but can also be present for spider bites.

Fang Marks

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Depending on the size and type of the spider that bites you, you may be able to see fang marks, or two small, side-by-side holes. Fang marks are sometimes seen with black widow bites.

Necrosis

Brown recluse spider bites can cause blisters that can, in turn, develop into ulcers. The venom in the bite can cause necrosis, or tissue death, around the bite site.

Signs That It May Not Be a Spider 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 bites
• 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.

Numerous Bites

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Multiple bites are not typically from spiders, especially not a brown recluse or black widow. In cases where there are multiple bites, they could be from insects that travel in groups, such as mosquitoes, bedbugs, or chiggers.

Occurrence

If you believe you've been bitten by a spider, knowing where it may have occurred can help you determine whether the spider was poisonous or not.

Brown recluse and black widow spiders prefer cool, dark places and are more likely to be found in an attic, barn, or wood pile.

If you have a rash or bite after working outdoors, it's possible that poison ivy, another type of insect, or a non-poisonous spider could be the culprit.

Timing

Brown recluse and black widow spiders are most active between April and October, when the weather is warmer and drier. Brown recluses are notoriously inactive during the rest of the year.

Red Center

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Though some spider bites can cause a small, red bump or redness in the area of the bite, a lesion with a red, inflamed center is not an indicator of a poisonous spider bite.

A skin infection is more likely. In fact, a lesion that is swollen, warm to the touch, or red at the center area could be a staph infection.

Brown recluse venom causes lesions that have dark, flat centers.

Chronic

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.

Large

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Brown recluse bites are known for having 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.

Ulceration

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Venom from the brown recluse spider can cause breaks in the skin (a process called ulceration) that worsen and spread, but it is a slow process that can take multiple weeks.

If you have a bite that ulcerates within a week, it's probably not from a brown recluse.

Swelling

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Brown recluse bites typically only cause significant swelling if the bite is on the head or feet. If you have a bite between the neck and ankles that swells, it is not likely to be from a poisonous spider. If you have extreme swelling from a bite on your face, contact your healthcare provider.

Exudes Moisture

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Though some spider bites cause blisters, brown recluse bites are known for being dry in the center. If it's oozing pus or moisture, it's very unlikely to be a brown recluse bite.

Summary

Bites or rashes of unknown origins can be alarming, especially if you do not know the cause. If you are fortunate enough to witness the bite, it can be helpful to capture the insect in a jar or box so that it can be identified. This will help your provider determine whether or not special treatment may be needed.

Regardless of what caused your bite, it's important to monitor the injury and watch for signs of infection or other complications. If you believe you are having an allergic reaction, contact your doctor right away.