Bug Bites and Stings: Everything You Need to Know

Millions and millions of Americans get bug bites or stings each year. While often mild, bug bites and stings can be serious in some cases — spreading infections like Zika virus, West Nile virus, and Lyme disease, or causing life-threatening allergic reactions.

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 open sores. 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 AgriLife Extension in San Angelo.

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.

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.

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 Rick Vetter, a retired entomologist at the University of California in Riverside. 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.

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.

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.

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?

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 your skin. But chigger bites often appear in clusters, and the bugs like to bite in hot, sweaty areas of your 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.

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.

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,” says Howard Russell, a retired entomologist at Michigan State University in East Lansing. “So if something an inch-and-a-half long lands and stings you, you’ll know it was a hornet.”

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.

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.

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.

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.

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.

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

The most common complication associated with bug bites is a secondary bacterial infection, usually caused by scratching or picking at a bug bite, Day says. Regardless of the type of bug bite, if you notice the bump or rash 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.

• Bug bites and stings can range from a minor annoyance to a life-threatening emergency.
• Insect bites can spread infections, including the Zika virus and Lyme disease, and some bites and stings can cause serious allergic reactions in some people.
• You can treat most bites and stings by cleaning the wound, applying ice, and using over-the-counter pain and anti-itch medicine.
• If you have symptoms of an allergic reaction, such as trouble breathing or swelling in your mouth and throat, get medical help right away.