Bug Bites and Stings: Everything You Need to Know

Millions and millions of Americans suffer from bug bites or stings each year. While often mild, in some cases bug bites or stings can be serious — or even life-threatening.

According to a study, roughly nine million Americans ended up in the emergency room as the result of a bug bite or sting. (1) The Centers for Disease Control and Prevention (CDC) has reported that rates of bite-related diseases and illnesses have ballooned in recent years. (2) Between 2004 and 2016, rates of Zika, West Nile, Lyme, and other bite-transmitted conditions roughly tripled. (Many factors likely contribute to this rise, the CDC says, including climate change and higher rates of international travel and commerce.)

So, how do you know which bugs and bug bites you should be concerned about?

Bug bites and stings come in all shapes, sizes, and severities — from itchy red lumps to pimply rashes and even large, rotting flesh lesions. And while most bug bites or stings have some distinct hallmarks (you’ll find much more on those below), experts are quick to point out that identifying an offending bug based only on its bite or sting can be a major challenge.

“A lot of the time, we’re not able to tell what pest bit someone from the bite alone,” says Charles Allen, PhD, a professor emeritus of entomology at Texas A&M University in College Station.

Other bug experts agree. “Different people react differently to bites,” says Lee Townsend, PhD, a professor emeritus of entomology at the University of Kentucky in Lexington.

Both Drs. Townsend and Allen say that unless a person actually sees the insect or arthropod that caused the bite or sting, it can be difficult (or impossible) for a doctor to say for sure what type of bug was at fault — or even if a bug was at fault.

Rick Vetter, a retired entomologist at the University of California in Riverside, says doctors might misdiagnose bacterial infections, including methicillin-resistant Staphylococcus aureus, as spider bites. (He co-authored a paper published in 2017 that warned doctors of the dangers of such misdiagnoses, which, according to the article, are not uncommon.) (3)

The bottom line is that correctly identifying and treating bug bites, stings, and rashes is important. Here’s what you should know about the signs and symptoms of some of the most common bug bites found in the United States, and what to do about them.

Only female mosquitoes bite. And the itchy red bump that often results is caused by proteins in the mosquito’s saliva, explains Jonathan Day, PhD, a professor emeritus of medical entomology at the University of Florida Medical Entomology Laboratory in Vero Beach.

In response to these saliva proteins, the human immune system releases a compound called histamine, which helps wound-healing white blood cells flood the area of the mosquito bite. It’s this histamine that produces all of your familiar mosquito bite symptoms. “The swelling, redness, and itch — that is your body responding to those foreign proteins,” Dr. Day says.

He notes that swabbing a bite with rubbing alcohol can relieve the itch. So can hydrocortisone and over-the-counter antihistamine drugs. Of course, mosquitoes can transmit a range of viruses and infections, from Zika and West Nile to dengue fever. If a person develops muscle aches, fever, or any other flu-like symptoms after being bitten, they should see a doctor. (4)

Learn More About Mosquito Bites

While spiders are often blamed for large or unusual skin lumps, sores, or lesions, experts say that spiders bite far less often than most people assume.

“People wake up in the morning, find a red mark, and immediately call it a spider bite,” says Vetter. But most of the skin issues that people pin on spiders are actually other types of bug bites or skin problems, he says.

What do legitimate spider bites look like? That depends on the type of spider, Vetter says.

Brown Recluse Spiders These bites sting, and they can resemble anything from small blisters — similar to mosquito bites — to large, rotting flesh sores, Vetter says. Along with a wide variety of skin symptoms, brown recluse bites can cause chills, fever, nausea, and other flu-like symptoms. (5) The venom in a brown recluse’s bite is poisonous and, in some rare cases, can result in a coma, kidney failure, or even death. 

Black Widow Spiders These bites can cause skin lesions, ranging from small red marks to angry, streaky red patches of inflamed or oozing skin. “But most of the reaction will be on the inside,” Vetter says. Black widow bites contain potentially deadly amounts of venom and tend to be painful right away. While that pain starts around the bite site, within an hour it often spreads to the chest or abdomen, depending on whether the bite occurred on the victim’s upper or lower body. Other symptoms can include everything from headaches, muscle weakness, and difficulty breathing to seizures, numbness, and painful muscle cramps.

Hobo Spiders, Wolf Spiders, House Spiders The bites of these and other domestic spiders do not contain venom that is of medical concern to humans, Vetter says. They can bite, but, he adds, the result is likely to be similar to a bee sting — meaning a sharp pain, followed by a painful, swollen red lump at the bite site. (6)

For nonvenomous spider bites, washing the injury with soap and water, applying ice, and taking over-the-counter pain or anti-itch medications are the best courses of action. But if you experience any of the systemic symptoms mentioned above — headaches, muscle weakness, flu-like symptoms — seek medical attention immediately. (7)

Learn More About Spider Bites

Nowadays, everyone’s worried about ticks and Lyme disease. And that worry is warranted. Ticks are proliferating rapidly, according to the CDC, with an estimated 476,000 Americans diagnosed and treated for Lyme disease annually, based on a 2021 estimate. That is 3 to 4 times higher than Lyme disease rates from just 30 years ago. (8)

The most straightforward way to identify a tick bite is to find a tick on your skin — whether it’s crawling free or its mouthparts are buried in your skin, says Richard Ostfeld, PhD, a distinguished senior scientist at the Cary Institute of Ecosystem Studies in Millbrook, New York. He says that ticks range in size from something smaller than a poppy seed to something as big as a jelly bean.

While tick bites tend not to itch or hurt like other bug bites, they can still cause a red welt or itchy lesion to rise on the skin after the tick has dropped away, Dr. Ostfeld says. If the tick transmitted Lyme disease pathogens into its victim’s skin, an expanding circular red rash, often in the shape of a bull’s-eye, may appear within a week to 10 days of the bite. (9)

If this sort of rash appears, or if a tick bite leads to muscle aches, headaches, nausea, or any flu-like symptoms, see a doctor immediately. These are all signs of serious tick-borne illnesses, including Lyme, and antibiotic treatments can help stop the illness. (10) If a tick is attached to your skin for less than 24 hours, your chance of getting Lyme disease is small. (10)

Learn More About Tick Bites

Fleas and mites aren’t related. (They’re actually totally different species.) But people often think of mites and fleas as similar because they’re tiny bugs that live in groups and can infest our homes and pets.

What differentiates mites from fleas?

Mites Several types of insect-like organisms that feed on animals or plants are classified as mites. (11) There are dust mites (which feed on human dander), house mouse mites (which like to feed on mice), and chicken mites (which feed on fowl), among others. Chiggers (see the next section) and scabies are also types of mites. Mites are close cousins with spiders and ticks, and they tend to show up in people’s homes only when rat, mouse, or bird nests are present, says Mike Merchant, PhD, a professor of entomology at Texas A&M University in Dallas. Mite bites tend to cause an itchy skin rash, which may feature small lumps or pimples. Treating these with anti-itch creams or ices can relieve the itching or redness, and the rash and lumps typically go away within a week, Dr. Merchant says.

Fleas These blood-sucking, wingless insects usually come into contact with humans via their pets or unwelcome crawl-space critters like possums or feral cats, Merchant says. Unlike most mites, fleas are large enough to see or feel on the skin, and their bite usually produces small red bumps that may be itchy and tend to appear in clusters of three or more. (12) Fleas don’t jump very high and are usually found low to the ground, so the rash they cause may often appear on the ankles or legs. Again, ice and anti-itch creams may help.

Both mites and, in particular, fleas can transmit potentially serious infections or diseases — including typhus and spotted fever. If a bite victim notices any nonlocalized symptoms, such as muscles aches or flu-like symptoms, see a doctor. (13)

Learn More About Flea and Mite Bites

Chiggers are an immature mite that lives outdoors in woody or overgrown areas. They feed on mammals, including humans, Townsend says. But chiggers aren’t bloodsuckers; they feed on cells and tissue, he explains.

Like many other insect bites, chiggers leave a small, inflamed red welt on the skin. But chigger bites often appear in clusters, and the bugs like to bite in hot, sweaty areas of a person’s body, especially inside of socks, at beltlines, or behind knees, Townsend says. If you notice groupings of red welts in these areas, there’s a good chance that chiggers are to blame.

Chiggers don’t transmit disease, and they drop off on their own, Townsend says. If you notice them, wash the area immediately with soap and water, then use ice or anti-itch cream to control the skin symptoms, which should fade in a week or less, he says.

Learn More About Chigger Bites

When it comes to biting and stinging ants in the United States, the most common culprit is the fire ant, which populates most of the American South and West, Merchant says. Because these tiny red ants like to build their nests in the middle of mown fields, garden plots, and other sunny places, it’s easy for people to end up stepping or kneeling down on them without realizing it and suffer dozens — or hundreds — of bites, he says.

A fire ant’s bite causes a painful, heat-filled stinging sensation, and a small red welt will form almost immediately. Within a day or two, this welt will often develop a white pustule that may be itchy or painful, he says.

Some other ants, namely red harvester or carpenter ants, also sting or bite. But those types are much less common than fire ant stings, Merchant says. Both tend to cause a stab of pain, similar to a bee sting, and a small red welt that may become itchy or painful.

In all cases — and like many other bug bites or stings — ants can transmit infections or illnesses. If a bite victim notices any muscle pain or flu-like symptoms, seek medical attention. The same goes for problems swallowing, swollen limbs, or any other signs of an allergic reaction. But if the symptoms are just red skin welts, washing them with soap and water and using over-the-counter anti-itch or pain meds should suffice. (14)

Learn More About Ant Bites and Stings

There are two hornet species that occur in the United States, according to Howard Russell, an entomologist at Michigan State University in East Lansing. There’s the European hornet (also called a giant hornet or a brown hornet), and the headline-making Asian giant murder hornet. You may have also heard of the bald-faced hornet, but contrary to its name, this insect is actually a wasp, Russell says.

At first glance, hornet stings are hard to distinguish from bee or wasp stings. However, given the size of the insect, chances are you’ll know when you’re dealing with a hornet. “Hornets are huge compared to wasps,” Russell says. “So if something an inch-and-a-half long lands and stings you, you’ll know it was a hornet.”

Like bee and wasp stings, hornet stings are painful. You’ll experience symptoms like swelling, warmth, redness, and itching at the site of the sting immediately after it happens. Symptoms tend to last about a day or two. (15)

If you do get stung, move to another area, “because you’re likely to get stung again if you’re near a nest,” Russell says. Then, remove the stinger from your skin (if there is one), wash the area with soap and water, and apply ice to ease pain and swelling. You can also apply 0.5 or 1 percent hydrocortisone cream (calamine lotion also works) to the sting multiple times a day until symptoms disappear, and take an antihistamine like diphenhydramine (Benadryl) to ease itching. (15)

However, hornet stings can cause more serious reactions if you’re allergic to the venom, or if you’ve been stung multiple times. Call 911 if you have trouble breathing or experience rapid heartbeat, nausea, cramps, vomiting, hives, dizziness or confusion, or swelling of the lips, eyelids, or throat. (15)

If you’re allergic — or think you may be allergic — to wasp, bee, and hornet stings, it’s a good idea to carry an epinephrine auto injector (an EpiPen or a generic version) with you if you know you’ll be outdoors, Russell says.

Asian giant murder hornets do pose cause for concern. They’re the largest known hornet species in the world, measuring 1.6 to 2 inches long. Their venom is toxic and stings are potentially deadly to humans if you’re stung multiple times. (16) But so far these hornets are rare in the United States; they’ve only been spotted in the state of Washington. And they likely pose a greater risk to honey bees. (16)

According to Russell, roughly 30 to 40 murder hornets will take over a honey bee nest by feeding on the larvae and honey. A few Asian giant hornets were discovered in Washington State in 2019, and efforts are underway to eradicate this invasive species. (16)

Despite there being thousands of species of wasps that exist in North America, not all are known to sting and not all that sting are known to be dangerous to people. (17) Social wasps like yellow jackets that live in large groups tend to be more aggressive around their nests, making them more likely to sting if you get too close, says Ben Hottel, PhD, an entomologist in the Atlanta area and a technical services manager for Rollins Inc. (the parent company of pest control company Orkin).

At first glance, wasps and hornets look very much alike. “The most obvious difference between the two is their size,” Dr. Hottel says. European hornets, for example, are roughly 1 inch long, whereas bald-faced hornets (in spite of their name, these are actually wasps) are only ½ inch long, according to Hottel.

If you’re stung by a wasp, you may experience pain, swelling, redness, and itching at the site of the sting. (18) Wash the area well with soap and water, and apply ice to ease swelling. An antihistamine cream or calamine lotion can help with itching.

Like hornet stings, wasp stings can cause a life-threatening reaction if you’re allergic, or if you’re stung in the mouth, nose, or throat area. Seek emergency medical care if you experience a sudden drop in blood pressure, dizziness, rapid pulse, stomach cramps, severe asthma, or swelling of the airways and throat. (19)

Learn More About Hornet and Other Wasp Stings

Bees are another common stinging insect, and can be hard to distinguish from wasps — unless you know what you’re looking for. “Bees and wasps are two closely related groups of insects, but there are some important differences,” Hottel says.

Visually, bees tend to be hairier than wasps; wasps usually have smooth, shiny skin. Bees and wasps also have different food preferences. “Bees are primarily pollinators and get all their food from flowers, whereas most wasps feed on other insects or are scavengers,” Hottel says.

However, like wasps, bees that are social (like honey bees) are more aggressive than solitary bees (such as carpenter bees), and therefore more likely to sting you, according to Hottel. Still, any type of bee (or wasp) can sting if they feel threatened.

For some people, bee stings can cause severe, potentially life-threatening allergic reactions. Signs and symptoms to watch for include hives; trouble breathing; swelling of the throat and tongue; a weak, rapid pulse; nausea, vomiting, or diarrhea; dizziness or fainting; and loss of consciousness. Call 911 if you experience any of these symptoms. (20)

Thankfully, bee stings are mostly just annoying. You’ll feel instant, sharp pain at the site, and then slight redness and swelling. Typically, these symptoms disappear within a few hours, but for some people, the swelling can take 5 to 10 days to resolve. (20)

You’ll know if you were stung by a bee if the stinger is still in your skin. Remove it with gauze or the tip of your fingernail — don’t use tweezers or squeeze the stinger. “There is a venom sac attached to the stinger and you can risk pumping more venom into the wound,” Hottel says.

Once the stinger is out, clean the area with soap and water. Apply ice to ease swelling, and antihistamine cream or calamine lotion to relieve itching.

Learn More About Bee Stings and What to Do About Them

Along with the biting or stinging pests mentioned above, a handful of others are also fairly common, and their bite symptoms are worth knowing.

• Bedbugs These bites typically look like clusters of small red welts — often on the face, neck, arms, or hands — although they may not be visible at all. (21) Most people identify bedbug bites after noticing skin welts and finding the small (but visible) bugs on their beds or mattresses. (22)
• Lice Bites from lice almost always affect a person’s scalp or other places where hair is present, and they are usually identified by an itchy sensation. (They’re often too small to see.)
• Black Flies These bites are painful and can cause anything from a small cut-like wound to a golf-ball-size lump. They can cause fever, headaches, and other serious reactions — all of which require medical attention, notes Purdue University. (23)

The most common complication associated with bug bites is a secondary bacterial infection, usually caused by scratching or picking at a bug bite with dirty fingernails, Day says. Regardless of the type of bug bite, if a person notices the skin issue becoming larger, redder, more painful, or more inflamed after a day or two has passed, that could indicate a bacterial infection, he says. The same holds for muscle aches, chills, fever, or other systemic symptoms.

If any of these bite symptoms emerge, see a doctor. You will likely be prescribed oral or topical antibiotics to get the infection under control, Day says.

Favorite Orgs for Essential Bug Bite Info

American Academy of Dermatology (AAD)

The AAD has more than 20,500 members and includes nearly every dermatologist in the United States. It’s an essential source for all things skin related, including bug bites. Type the particular bite you’re curious about into the search bar and explore well-researched information about its symptoms, causes, treatments, and tips on how to deal with it. There’s also a useful page that outlines when it’s time to visit a dermatologist or the emergency room.

American Lyme Disease Foundation (ALDF)

This foundation’s website offers a detailed look at Lyme disease as a whole, including information on how to prevent ticks on your property and how to identify types of ticks, as well as debunking common myths surrounding Lyme disease.

Cleveland Clinic

Cleveland Clinic has information on a variety of illnesses and common health problems. It also has information on what you should do about spider bites, tick bites, and mosquito bites, as well as other bug topics. You can also find out more about the clinic’s ongoing research and connect with providers.

KidsHealth

KidsHealth is an online source of health information to help children and families. The site is run by the nonprofit Nemours. It has information for both parents and kids. And when it comes to bug bites, KidsHealth has information on brown recluse spider bites, mosquito bites, tick bites, and more.

Mayo Clinic

The Mayo Clinic’s patient information section of its site includes information on spider bites, bee stings, tick bites, and more. Learn about health information, connect with providers, and find out about ongoing research at the clinic.

U.S. Environmental Protection Agency (EPA)

This government agency protects both environmental and human health, and, accordingly, the site features useful information about bug bites. The breadth of content differs for the different types of bug bites. For example, the site has very thorough resources about bedbugs, ticks, and mosquitoes. The site also features a handy tool that allows you to determine the best insect repellent for you based on the insects you need protection from, for how long, and any specific ingredients you’re looking for.

Favorite Resource for How to Avoid Bug Bites (and Related Diseases) While Traveling

Centers for Disease Control and Prevention (CDC)

The CDC is the government agency within the U.S. Department of Health and Human Services tasked with increasing the health security of the country and protecting Americans from disease. The CDC’s website has guides on different types of bug bites and potential disease they may spread. You’ll also find helpful travel warnings about bug bites and bug-borne diseases.

Favorite Resource to Identify Bug Bites

Orkin

This pest-control company serves more than 1.7 million residents and businesses around the world. Suffice to say: It knows bugs, and it has put together a useful identification guide to help you narrow down what bit you, based on photos, the appearance of the bite, and accompanying symptoms.

Favorite Sources for Bug Spray and Insect Repellent Information

Consumer Reports

Consumer Reports is known for its consumer product ratings. The group’s insect repellent buying guide gives you information on different types of insect repellent, what to look for when buying one, and a comparison of how different products tested against one another. (Yes, the testing process involves volunteers getting bitten by all sorts of insects. Read about that process on the site, too.)

Recreational Equipment Inc. (REI)

REI is an outdoor gear and apparel retailer. But in addition to the supplies it sells, the brand also hosts classes and events for outdoor activities and provides a lot of helpful information on its site — including an everything-you-need-to-know explainer on the different types of insect repellent options (including sprays, lotions, clothing, and airborne solutions).

With additional reporting by Lauren Bedosky.