You probably came across this article because you or a loved one has been bitten by an insect and wondering if what you are looking at has been bitten by a spider bite. Photos of spider bites can help determine the culprit, but bites from other insects can also look very similar.
This article presents pictures of the different types of skin lesions and looks at whether they could be the result of a spider bite. However, unless you actually catch a spider in the act, the only sure way to determine if a spider has bitten you is to consult a doctor.
The good news is that while more than 50 spiders in the US have venom, their bites are not serious and only cause mild pain or redness. Only two are poisonous to humans: the black widow and the brown hermit.
Signs of a possible spider bite
Below are signs that you may have been bitten by a spider.
Expansion of lesions
A growing, spreading, or spreading lesion can have multiple causes, including a spider bite. Although this type of injury is common with brown recluse bites, It could also be a sign of another skin infection, such as impetigo .
If you are not sure if the defeat is growing, circle it with a line. This will help you track if the rash or area of swelling is expanding. Be sure to write down the time and date the line was drawn so you can tell how fast the injury is spreading.
A rash on the target, known as erythema migrans , can be a symptom of a bite from an insect called an arthropod. Spiders and ticks are varieties of arthropods.
Bullseye rash is most common with tick bites, which lead to Lyme disease , but it can also occur with spider bites.
Depending on the size and type of spider biting you, you may see fang marks or two small holes next to each other. Fang marks are sometimes seen on black widow bites.
Brown recluse spider bites can cause blisters, which can turn into sores. Venom at the sting site can cause tissue necrosis or death around the sting site.
Rashes, necrosis, widened lesions, or fang marks at the wound site are signs that the bite could be from a spider, including poisonous ones like black widows or brown recluses. Examine the area carefully and see your doctor if your symptoms get worse.
Signs that it may not be a spider bite
DO NOT DISCONNECT is an acronym for signs that the wound or injury was not caused by a brown recluse bite. It means:
- Numerous bites
- Red center
- U ulcerate too soon
- S wollen
- Eliminate moisture
The presence of any of these is a sign that the wound is not from a brown recluse. Having two or more of these signs almost guarantees that they are not. Let's take a look at each of them.
Multiple bites usually come from non-spiders, especially brown recluses or black widows. In cases where there are multiple bites, they can be from insects that travel in groups, such as mosquitoes, bed bugs , or chiggers .
If you think you have been bitten by a spider, knowing where it may have happened can help you determine whether or not the spider was poisonous.
Brown recluse spiders and black widows prefer cool, dark locations and are most common in the attic, shed, or pile of wood.
If you get a rash or bite after working outside, it could be poison ivy, another type of insect, or a non-poisonous spider.
Hermit spiders and black widows are most active between April and October, when the weather is warmer and drier. Brown hermits are known to be inactive for the rest of the year.
Although some spider bites can cause a small red bump or redness at the bite area, a lesion with a red, inflamed center is not a sign of a poisonous spider bite.
A skin infection is more likely. In fact, a warm-to-touch or red swelling in the center could be a staph infection .
The venom of the brown recluse causes lesions with dark, flat centers.
If it takes a long time to heal, it may not be a brown recluse bite. They have a reputation for being persistent for a while, but most brown recluse bites heal in three weeks and the largest heal in three months.
Brown recluse bites are known to have dead tissue at the center of the injury. However, the necrosis will be no more than 10 centimeters wide (four inches). Many infected ulcers are identified, even diagnosed, as spider bites. In truth, unless you have a spider to identify as the culprit, the chances of a spider bite are slim.
If you have a skin lesion that grows or continues to get worse for 24 hours, it is worth seeing a doctor. If not, it's probably best to keep it clean and see if it changes.
Venom from a brown recluse spider can cause skin tears (a process called ulceration) that get worse and spread, but this is a slow process that can take several weeks.
If you get a bite that ulcerates in a week, it is probably not from a brown recluse.
Brown recluse bites usually cause significant swelling only if they bite the head or feet. If you have a swollen bite between your neck and ankles, it is most likely due to a poisonous spider. If your face is very swollen from the bite, see your doctor.
Any insect bite can cause swelling as a result of an allergic reaction or poisoning.
While some spider bites cause blisters, brown recluse bites have been known to dry in the center. If pus or moisture is oozing, it is highly unlikely that it is a brown recluse bite.
Even if a black widow or brown recluse spider can be ruled out as a cause, it is important to pay attention to insect bites, skin lesions, or other wounds, especially if it is not known what caused them. Talk to your healthcare provider if you have a skin ulcer that loses moisture, takes a long time to heal, or causes swelling of your face, hands, or feet. These could be signs of an allergic reaction or a skin infection that requires treatment.
A sting or rash of unknown origin can be alarming, especially if the cause is unknown. If you are lucky enough to witness a bite, it can be helpful to trap the insect in a jar or box so it can be identified. This will help your provider determine if special treatment may be necessary.
Regardless of the cause of the bite, it is important to keep an eye on the injury and watch for signs of infection or other complications. If you think you have an allergic reaction , see your doctor right away.
Frequently asked questions
In North America, black widow and brown recluse bites are more likely to cause severe symptoms. With a black widow bite, you may feel pain right away, followed by shortness of breath, puffy eyes, headache, excess saliva, nausea, cramps, sweating, and rashes. Brown recluse spider bites don't cause immediate pain, but they can cause itchy bruises and blisters.
Only if you are allergic to wolf spider venom, and most people are not. Wolf spider bites are usually as strong as a bee sting and cause redness and pain that should disappear within 24 hours.
Call 911 immediately if you have the following symptoms:
- Difficulty breathing or wheezing
- The person has passed out or is too weak to stand.
Seek medical attention if the bite seems to be spreading or the person appears very ill or has a fever.