First Aid Bites & Stings Spider Bite Pictures Skin issues and whether or not a spider could be to blame By Rod Brouhard, EMT-P Rod Brouhard, EMT-P Facebook LinkedIn Twitter Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients. Learn about our editorial process Updated on January 20, 2022 Medically reviewed Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. These medical reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Michael Menna, DO Medically reviewed by Michael Menna, DO Michael Menna, DO, is board-certified in emergency medicine. He is an attending emergency medicine physician at White Plains Hospital in White Plains, New York and also works at an urgent care center and a telemedicine company that provides care to patients across the country. Learn about our Medical Expert Board Print 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. Some other signs and symptoms can overlap, too. This article provides photos of different types of skin lesions and discusses whether or not they could be from a spider bite. This, however, can't help you reach a concrete diagnosis. 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 professional. The good news is that though more than 50 spiders in the United States have venom, their bites are not serious and usually only cause redness, swelling, and pain. Only two are poisonous to humans: the black widow and the brown recluse. Signs of a Possible Spider Bite Though it is possible to have a reaction to bites from any type of spider, most of the time, a non-venomous spider bite will not cause major problems. Black widow and brown recluse bites are more serious. Brown recluse spider bites are known for causing blisters, ulceration, and, in some cases, cell death (necrosis) and scarring over a period of time. Black widow venom works quickly, with symptoms often appearing within an hour of being bitten. Symptoms of a black widow bite include: Muscle cramps or spasmsSweatingHeadacheSevere pain in the chest, back, or abdomenChills, fever, or nausea (with or without vomiting) If you suspect that you've been bitten by a black widow spider, seek medical help right away. The following are signs that you may have been bitten by a spider. Expanding Lesions There are many different things that can cause a lesion that grows, expands, or spreads—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. How to Tell if You Were Bitten by a Brown Recluse Spider Bullseye Rash This photo contains content that some people may find graphic or disturbing. See Photo Jake from Atlanta A bullseye rash—known as erythema migrans—can be sign of a bite from a type of bug called an arthropod. Spiders are arthropods (but so are ticks). Bullseye rashes are most common in tick bites that result in Lyme disease, but can also be present with spider bites. Fang Marks This photo contains content that some people may find graphic or disturbing. See Photo Exodog 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. Understanding How Black Widow Bites Are Diagnosed 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. Recap Bullseye rashes, necrosis, expanding lesions, or fang marks at the wound site could be from a spider bite, including poisonous ones like the black widows or brown recluse. Get medical attention so you can get a proper diagnosis and treatment. Signs That It May Not Be a Spider Bite The first priority is not necessarily ruling out that you were bitten by a spider, but if you were bitten by a poisonous spider. 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 bitesOccurrenceTimingRed centerElevatedChronicLargeUlcerates too earlySwollenExudes 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. Some of these are also signs that you are not likely dealing with a black widow bite or a bite from any spider altogether, for that matter. Numerous Bites This photo contains content that some people may find graphic or disturbing. See Photo T. Critchley In cases where there are multiple bites, they could be from insects that travel in groups, such as mosquitoes, bedbugs, or chiggers. Multiple bites are not typically from spiders, especially not a brown recluse or black widow. Occurrence 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 cause. Brown recluse and black widow spiders prefer cool, dark places and are more likely to be found in an attic, barn, or wood pile. Timing Most spiders are more numerous from late summer into fall, during mating season. When outdoors in the winter, they go into a dormant state. Brown recluse and black widow spiders, however, 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 This photo contains content that some people may find graphic or disturbing. See Photo Danielle from Binghamton, NY 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. Spider Bite vs. Infection Elevated If your bite is a raised bump, it may be from a spider, but not a brown recluse. 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 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 cause, the odds are against a spider bite. Ulceration Aliaksandr Litviniuk / Getty Images Venom from the brown recluse spider can cause breaks in the skin that worsen and spread. But this process, known as ulceration, is a slow one that can take multiple weeks. If you have a bite that ulcerates within a week, it's probably not from a brown recluse. Swelling This photo contains content that some people may find graphic or disturbing. See Photo CDC 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, see a doctor prompty. Any bug bite can lead to swelling from an allergic reaction or envenomation. Exudes Moisture This photo contains content that some people may find graphic or disturbing. See Photo (c) Gary Goode 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. Recap A skin lesion that is ulcerated, oozing moisture, taking a long time to heal, or is causing swelling on the face, hands, or feet could be from an allergic reaction or a skin infection that requires treatment. When to Call a Doctor Though not all insect or spider bites will require a doctor's attention right away, there are some situations where you should seek treatment. Get medical attention if: You show signs of an allergic reaction, such as whole-body itching, hives that spread, or swelling of the throatYou believe that you've been bitten by a poisonous insect, like a black widow spiderYou develop a bullseye rash (this could be a sign of Lyme disease) Even if these don't apply, but your skin lesion grows or continues to get worse over a 24-hour period, you should see the doctor. If not, it's probably fine just to keep it clean and watch to see if it changes. Summary 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. A Word From Verywell If you witness the bite, it can be helpful to capture the insect in a jar or box so that it can be identified—or to try to take a photo. This will help your doctor determine whether or not special treatment may be needed. Frequently Asked Questions What are the symptoms of a serious spider bite? In North America, black widow and brown recluse bites are most likely to cause serious symptoms.With a black widow bite, you might feel pain immediately, and then have difficulty breathing, swollen eyes, headache, excess saliva, nausea, cramps, sweating, and rash.Brown recluse spider bites don’t hurt immediately but can cause a bull’s eye bruise and blisters with itchiness. Are wolf spider bites dangerous? Only if you happen to be allergic to the wolf spider’s venom, and most people are not. Wolf spider bites are typically about as bad as a bee sting, causing redness and pain that should go away in within 24 hours. When should I get emergency help for a spider bite? Call 911 immediately for the following signs:Trouble breathing or wheezingPerson has fainted or is too weak to standCall a doctor for advice if the bite seems to be spreading or if the person looks very sick or has a fever. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 15 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Seattle Children's Hospital. Spider Bite. Cleveland Clinic. Spider bites. University of Michigan Health. Black widow spider bite. Forks TP. Brown recluse spider bites. J Am Board Fam Pract. 2000;13(6):415-23. Cleveland Clinic. Impetigo. Cordeiro FA, Amorim FG, Anjolette FA, Arantes EC. Arachnids of medical importance in Brazil: main active compounds present in scorpion and spider venoms and tick saliva. J Venom Anim Toxins Incl Trop Dis. 2015;21:24. doi:10.1186/s40409-015-0028-5 Johns Hopkins Medicine. Spider Bites. Stoecker WV, Vetter RS, Dyer JA. NOT RECLUSE-A mnemonic device to avoid false diagnoses of brown recluse spider bites. JAMA Dermatol. 2017;153(5):377-378. doi:10.1001/jamadermatol.2016.5665. Rader RK, Stoecker WV, Malters JM, Marr MT, Dyer JA. Seasonality of brown recluse populations is reflected by numbers of brown recluse envenomations. Toxicon. 2012;60(1):1-3. doi:10.1016/j.toxicon.2012.03.012 Stoecker WV, Vetter RS, Dyer JA. NOT RECLUSE—a mnemonic device to avoid false diagnoses of brown recluse spider bites. JAMA Dermatol. 2017;153(5):377. doi:10.1001/jamadermatol.2016.5665 Mikkelsen J, Schmidt G, Holmgaard R. Reconstructive considerations following a necrotic spider bite on the face: A case report. Int J Surg Case Rep. 2017;32:76-79. doi:10.1016/j.ijscr.2017.02.023 Payne KS, Schilli K, Meier K, et al. Extreme pain from brown recluse spider bites: model for cytokine-driven pain. JAMA Dermatol. 2014;150(11):1205-8. doi:10.1001/jamadermatol.2014.605 Rahmani F, Banan khojasteh SM, Ebrahimi bakhtavar H, Rahmani F, Shahsavari nia K, Faridaalaee G. Poisonous spiders: bites, symptoms, and treatment; an educational review. Emerg (Tehran). 2014;2(2):54-8. PennState Extensions. Wolf spiders. Seattle Children’s Hospital. Spider bite. Additional Reading Murphy C, Hong J, Beuhler M. Anaphylaxis with Latrodectus Antivenin Resulting in Cardiac Arrest. J Med Toxicol. 2011;7(4):317-321. doi:10.1007/s13181-011-0183-1 Vetter R, Swanson D, Weinstein S, White J. Do spiders vector bacteria during bites? The evidence indicates otherwise. Toxicon. 2015;93:171-174. doi:10.1016/j.toxicon.2014.11.229