Getting a bug bite can be a concerning experience, especially if you don’t know what type of tiny creature left you with that red, throbbing welt on your skin. Don’t panic — most bug bites and stings from common insects are harmless and heal quickly.

But some bug bites and stings, like those from fire ants, wasps, hornets, and bees, may cause intense pain or even a serious allergic reaction. Others, like poisonous spider bites, require immediate emergency medical care.

Unsure of what bit you? Here are 12 bug bites and what they look like.

A mosquito bite appears as an itchy, round red or pink skin bump. It’s usually a harmless bug bite, but it can sometimes cause a serious illness like the Zika virus.That said, the Centers for Disease Control and Prevention (CDC) refers to most mosquitoes in the United States as “nuisance mosquitoes.” These mosquitoes may appear immediately after heavy rains or natural disasters, but they don’t spread the types of germs that can make people sick.

So that itchy little bump may be annoying, but it likely won’t cause any additional symptoms to develop.

Bedbug bites can occur anywhere on your body, but they typically show up on uncovered areas, such as your neck, face, arms, and hands.You probably won’t feel pain when a bedbug bites, but you may see three or more clustered red marks, often forming a zigzag. These marks might show up as many as 14 days after a bite occurs, since bed bugs inject a substance in their saliva that makes bites harder to spot.Although they’re common and irritating, bedbugs do not carry disease. But some people develop a mild or severe allergic reaction. This can result in a raised, red skin bump, blister, or a welt known as hives.

If you have hives, a lot of bites, or notice a bite that looks infected, talk with your doctor.

Most spider bites aren’t poisonous. But a bite from a venomous spider (like a black widow) is extremely dangerous and can cause a severe, potentially fatal reaction.When a black widow bites, it may feel like a small pinprick, followed by minor swelling and redness. A target-shaped sore may also appear.Within an hour, the bite may also cause a dull muscle pain to spread from the bite area across the body. The pain will mostly be felt in your chest if the bite is on your upper body, with most of the pain occurring in your abdomen if you’re bitten on the lower half of your body.Other symptoms may include:

• Anxiety

• Headache

• Trouble breathing

• Increased saliva or sweating

• High blood pressure

• Restlessness

• Weakness in the muscles

• Sensitivity to light

• Vomiting and nausea

• Painful muscle spasms or cramps

• Numbness or tingling around the site of the bite that sometimes spreads out

• Facial swelling (during the hours following the bite)

In children, seizures may occur if the bite is fatal. Pregnant women may also go into labor or experience contractions.The brown recluse spider is venomous and usually lives in dark and unused spaces. According to the Pennsylvania State University College of Agricultural Sciences, brown recluse spiders are established mostly in southern and midwestern states, with appearances outside of those areas considered rare.This spider bite is usually painless, with symptoms developing over the next two to eight hours.In the hours afterward, the bite may become more painful and look like a bruise or blister with a blue-purple area around it, similar to a bull’s-eye. Later, the bite becomes crusty and develops scarring.Symptoms of a brown recluse spider bite occur within a few hours and include:

• Fever

• Chills

• Itching

• Nausea

• Sweating

Unless the tick is still attached, their bites can be hard to spot and many go without detection. These bites are usually red and itchy, and they can be easily mistaken for mosquito bites at first.Some tick bites can be dangerous because they may carry diseases like Lyme disease. Symptoms of Lyme disease sometimes include a skin rash in a pattern of rings, much like a bull’s-eye on a target, which appears up to a month after the tick bite.

Symptoms of flea bites may begin within hours after you’re bitten. The bites tend to appear patterns of three or more, which is known as the “breakfast, lunch, and dinner” sign.Flea bites usually appear on the legs and places where clothing is close against the body. This could include the waist, thighs, lower abdomen, or buttocks. If a person has an allergy to flea bites, blisters may form.

Bee stings cause a sharp pain that may continue for a few minutes. This pain usually lasts for a few hours, but the area may still feel sore to the touch a few days later.A red skin bump and swelling may appear around the site of the sting. Some people have a moderate reaction that sees swelling increase over the next few days.Bee venom causes swelling where the sting occurred or may affect an entire area of your body, including your throat and lungs. If you have this type of allergic response, called anaphylaxis, it is a medical emergency that needs treatment immediately.

Lice bites are tiny red bumps on the shoulders, neck, scalp, and other areas from small parasitic insects called head lice, body lice, or pubic lice, which can live on your clothes or in your bedding.

Because lice bites are so small, they usually don’t hurt, but they do itch. The first time a person has lice, the itching may not start for four to six weeks. Some people may develop a large, uncomfortable skin rash from lice bites, especially if they scratch and infection develops.

Ant bites and stings are typically painful and cause red skin bumps. Some types of ants, like fire ants, are venomous, and their bites can cause severe pain and a red spot — these are hives that stay in the same area and are the most common reaction.A few hours after a bite, there may be white, fluid-filled pustules or blisters that develop and last for several days to a few weeks.Ant bites may also lead to hives, itching, and redness that can develop farther from the bite, along with digestive issues such as nausea, belly cramps, and diarrhea.

There are multiple types of mites that can bite people, with the most common being chiggers.Chiggers are the larvae of a specific mite species. In response to a chigger bite, the surrounding skin becomes irritated and inflamed, and an itchy red welt develops that leads to severe itching that may last up to a week. The bites are usually undetectable until itchy, red marks develop that may look like a skin rash.Chigger bites normally appear on the ankles, behind the knees, and on the ankles, waist, or groin — especially in areas where clothing closely meets the skin, like sock or underwear lines.

Hornet and wasp stings are usually painful, swollen, and itchy immediately after happening. Bleeding or redness may occur at the site of the sting, without any long-term effects.But if you’re allergic to bee, wasp, or hornet stings — or you’ve experienced multiple stings — a sting can cause severe allergic reactions, including:

• Nausea

• Rapid heartbeat

• Swelling

• Dizziness

• Hives

• Shortness of breath

Despite their names, horseflies and deer flies can still target humans who are outside. Bites can be extremely painful and cause the following symptoms:

• Bleeding

• Swelling

• Irritation

• Hives

• Allergic reaction

• Anaphalaxis

How to Prevent Bug Bites

The CDC suggests the following to reduce the risk of bug bites:

• Reduce activities that increase exposure to insect bites, such as camping, hiking, or interactions with wild animals. Where this isn’t possible, take precautions as necessary.

• Understand the particular insects that thrive in locations you’re visiting or nearby. Not all insects pose a risk everywhere in the country.

• Use an insect repellent that the manufacturers have registered with the U.S. Environmental Protection Agency. (The agency has published an online tool to help you determine which one is appropriate in many varying conditions.)

• Use permethrin on clothes and outdoor equipment.

• Sleep beneath a mosquito net if a mosquito screen is not present in your room.

• When traveling, find out what shots or medicines you may need and any precautions you can take.

• Wear clothing that covers the skin.

• Shower after spending time outdoors to reduce the risk of tick-borne diseases.

Be sure to report any symptoms, such as fever, to a doctor if you’ve spent time outdoors or abroad. They may be able to help you identify diseases from bug bites and begin treatment as soon as possible.

• Bug bites and stings take many forms, from the often mark-free itching of lice to the intense pain and bleeding of horsefly bites.

• Sometimes people can have allergic reactions to bites, which can lead to more severe skin reactions or symptoms throughout the body, and transmitted diseases can lend bites a unique appearance.

• While many bites may only cause minor discomfort, some may cause severe allergic reactions that require immediate medical attention.

• Monitor any bites or stings that you find, and visit a doctor if symptoms get worse or continue beyond what usually occurs.