Getting a bug bite can be a creepy experience, especially if you don’t know what 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.
Symptoms of bug bites provide clues to the cause and severity. For example, most bug bites cause red bumps with pain, itching, or burning. Some bug bites also feature blisters or welts. Here are some common bug bite clues:
- Bedbugs leave a small bite mark on the skin that is red and itchy or in rare cases causes a serious allergic reaction.
- Bee stings cause a red skin bump with white around it.
- Flea bites leave an itchy welt on the skin, often on the ankles and legs.
- Mosquitoes leave a raised, itchy pink skin bump or in rare cases a severe allergic reaction.
- Spider bites cause minor symptoms like red skin, swelling, and pain at the site or very serious symptoms that need emergency care.
- Ticks can carry Lyme disease, and their bite leaves a rash that looks like an expanding bull’s-eye.
Most bug bites are transmitted directly from the insect and occur outdoors. Two exceptions are bedbugs (tiny mites that live in and near beds) and lice, which spread through contact with an infected person, a comb, or clothing.
Certain bug bites can also spread illnesses, such as Zika virus, West Nile virus, Chikungunya virus, Dengue fever, and yellow fever (all transmitted by mosquitoes); Lyme disease (from ticks); Rocky Mountain spotted fever (from dogs or wood ticks); and Chagas disease (from kissing bugs).
In a report posted May 4, 2018, the Centers for Disease Control and Prevention (CDC) cautioned Americans that diseases from mosquito, tick, and flea bites have soared in recent years.
How can you prevent bug bites? Here are some tips from the CDC:
- Use an insect repellent that’s been registered with the Environmental Protection Agency (EPA). (The EPA has published an online tool to help you determine which one is appropriate in many varying conditions.)
- When traveling, find out what shots or medicines you may need and any precautions you can take.
- Wear clothing that covers the skin.
No matter what type of bug bite you have, it is good to know what bit you. Learning to identify a bug bite by how it looks and feels will help you know whether to treat the bug bite at home or seek immediate medical care.
If you have known allergies to bug bites, talk with your physician about emergency care. Some people with severe allergies to bug bites need to have allergy medicine, including epinephrine (such as an EpiPen), with them always.
Mosquito Bites Can Cause a Serious Illness
A mosquito bite appears as an itchy, round red or pink skin bump. It's usually a harmless bug bite but can sometimes cause a serious illness, such as the Zika virus (particularly harmful in pregnant women), West Nile virus, malaria, or eastern equine encephalitis (EEE). For most people, Zika causes a brief, flulike illness. But newborns of pregnant women infected with Zika have an alarming rate of microcephaly birth defects. Check out the CDC’s Zika Travel Information page to find out more about travel warnings and advisories.
For 2019 (the most recent year for which data is available), a total of 958 cases of the West Nile virus were reported across 47 states in the United States, according to the CDC. Symptoms appear 2 to 14 days after the bite and can include headaches, body aches, fever, vomiting, diarrhea, and a skin rash. People with a more severe West Nile infection may develop meningitis or encephalitis, and have symptoms including neck stiffness, severe headache, disorientation, high fever, and convulsions.
The bite of a parasite-infected mosquito can cause malaria, a rare occurrence in the United States, with only about 2,000 cases diagnosed in the country each year (and the majority of those in people who recently traveled to parts of the world where malaria transmission is more common), according to CDC data. Symptoms are similar to the flu and can include fever, headache, muscle aches, nausea, and vomiting from 10 days to four weeks after the bite. Malaria is serious, but it's good to know it is preventable and treatable, according to the CDC.
Cases of EEE are rare but deadly. For people infected with EEE, 30 percent do not survive, and many who do develop neurological problems. As of mid-December 2019, 38 cases had been reported for the year in the United States, including 15 individuals who died from the condition, according to the CDC. But the numbers are concerning given that they’ve increased from the usual seven cases reported annually, according to CDC data. Most of the cases have been reported in the Northeast.
Another emerging concern is a species of mosquito just found in Florida, called Aedes scapularis. Previously found mostly in the Caribbean and Latin America, research indicates the mosquito is now well-established in Florida. The invasive species has been found in Broward and Miami-Dade counties, according to a report published in March 2021 in the Journal of Medical Entomology. It’s unclear if the Aedes scapularis mosquitos in Florida are spreading any types of disease, but elsewhere they have been shown to spread some viruses, including the Venezuelan equine encephalitis virus (VEEV) and the one that causes yellow fever.
What Do Bedbug Bites Look Like?
You probably won't feel pain when a bedbug bites, but you may see three or more clustered red marks, often forming a line. Some people develop a mild or severe allergic reaction to the bug's saliva between 24 hours and 3 days later. This can result in a raised, red skin bump or welt that's intensely itchy and inflamed for several days.
If you have hives, get many bites, or notice a bite that looks infected, you should visit a board-certified dermatologist for treatment, according to the American Academy of Dermatology. Bedbug bites can occur anywhere on your body but typically show up on uncovered areas, such as your neck, face, arms, and hands. It's good to know that although they're common, bedbugs do not carry disease, according to the CDC.
When to See the Doctor for Spider Bites
Most spider bites are not poisonous and cause only minor symptoms like red skin, swelling, and pain at the site. Other spider bites are a real emergency. If you develop an allergic reaction to a spider bite, with symptoms such as tightness in the chest, breathing problems, swallowing difficulties, or swelling of the face, you need medical care at once. Because spider bites can get infected with tetanus, the CDC also recommends staying on top of your tetanus booster shots and getting one every 10 years.
A bite from a poisonous spider like the black widow or brown recluse is extremely dangerous and can cause a severe reaction. The black widow's bite, which shows up as two puncture marks, may or may not be painful at first. But 30 to 40 minutes later, you may have pain and swelling in the area. Within eight hours, you may experience muscle pain and rigidity, stomach and back pain, nausea and vomiting, and breathing difficulties. You might not have seen the spider that bit you, but always seek medical attention immediately if there's a possibility you could have been bitten by a poisonous spider. Call 911 or the American Association of Poison Control Centers at 800-222-1222.
Brown Recluse Spider Bites Need Immediate Medical Attention
The brown recluse spider is poisonous and usually lives in dark and unused spaces. Some people feel a small sting followed immediately by a sharp pain, while others don't realize they've gotten a brown recluse bite until hours later. Four to eight hours afterward, the bite may become more painful and look like a bruise or blister with a blue-purple area around it. Later, the bite becomes crusty and turns dark. It’s also worth noting that this type of spider is found in several Midwestern states, western parts of some Southern states (including Kentucky, Tennessee, and Georgia), and the central Southern states (including Texas, Louisiana, Alabama, Mississippi, Arkansas, and Missouri) — and they’re rarely found outside of these areas, according to the University of Kentucky.
Symptoms of a brown recluse spider bite occur within a few hours and include fever, chills, itching, nausea, and sweating. Because some people will have a serious reaction that can lead to kidney failure, seizure, and coma, it's important to get medical care at once, according to the National Institutes of Health (NIH) National Library of Medicine. Be sure to seek medical attention immediately if you could have been bitten by a poisonous spider; call 911 or the American Association of Poison Control Centers at 800-222-1222.
Some Ticks Carry Lyme Disease
Some tick bites can be dangerous because the insects may carry disease. Black-legged ticks, formerly known as deer ticks, may carry Lyme disease, and dog ticks can spread Rocky Mountain spotted fever. Up to 30,000 cases of Lyme disease are reported each year in the United States.
Symptoms of Lyme disease include a skin rash in the pattern of rings, much like a bull’s-eye on a target, that appears up to a month after the tick bite. You may also have fever, fatigue, headaches, muscle and joint aches, as well as irregular heart rhythms. But 20 to 30 percent of people who get infected never develop a rash. Symptoms such as swollen or painful joints, memory loss, or other autoimmune responses that mimic those of other diseases may present themselves when Lyme disease is in its advanced stages. A diagnosis may remain elusive because many doctors will not initially equate these nonspecific symptoms with Lyme disease.
Rocky Mountain spotted fever from a tick bite is rare, with about 2,500 cases per year in the United States. It causes a fever, a headache, muscle aches, and a skin rash. The rash of pinpoint red spots begins on the ankles and wrists after a few days of fever, but later the rash spreads to the rest of the body; in some people, a rash never develops. Although this infection can be severe — and even fatal — it is preventable and can be successfully treated with prompt medical care, according to the CDC.
Another type of tick to avoid is the lone star tick. It’s found in the eastern part of the United States, but mainly in the south. It can transmit several viruses, the CDC notes. Most notably, allergic reactions associated with consumption of red meat have been reported by people who’ve been bitten by these ticks, according to the CDC.
Flea Bites Can Lead to Skin Infections
Symptoms of flea bites may begin within hours after you're bitten, and the bites tend to appear in groups of three or four. You may notice itching, hives, and swelling around an injury or sore, or a rash of small, red bumps that may or may not bleed. Flea bites are most common on your ankles and legs, but may also appear in your armpits, around your waist, and in the bends of your knees and elbows. A flea-bite rash turns white when you press on it and tends to get larger or spread over time. Scratching the rash can lead to a skin infection, according to the NIH National Library of Medicine, and may need medical attention.
In extremely rare cases, fleas are infected with the bacteria that causes plague. The disease can spread from wild rodents to pets and people. Over the past 10 years, as few as 1 and as many as 17 cases of plague were reported in the United States, according to the CDC, most in the rural West. Symptoms of plague include swollen lymph nodes, headache, fever, and chills that appear from one to six days after the bite.
Bee Stings Can Result in Severe Allergic Responses
Bee stings cause a sharp pain that may continue for a few minutes, then fade to a dull, aching feeling. The area may still feel sore to the touch a few days later. A red skin bump with white around it may appear around the site of the sting, and the area may itch and feel hot to the touch. If you've been stung by a bee before, your body may also have an immune response to the venom in the sting, resulting in swelling where the sting occurred or in 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. Symptoms of a severe allergy to a bee sting include hives, swelling, trouble breathing, dizziness, cramps, nausea, diarrhea, and even cardiac arrest.
Lice Bites Cause Itchy, Tender Spots
Lice bites are tiny red spots on the shoulders, neck, and scalp from small parasitic insects that can live on your clothes or in your bedding. Because lice bites are so small, they usually don’t hurt, but they do itch. Some people may develop a larger, uncomfortable skin rash from lice bites. Continual scratching of the itchy spots could lead to an infection, marked by symptoms including swollen lymph nodes and tender, red skin. An infected lice bite may also ooze and crust over; it will need to be treated by a doctor, but lice are not known to carry other diseases.
Ant Bites and Stings Can Become Infected
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 a severe allergic reaction. Fire ants bite first to hold on and then sting, giving a sharp pain and a burning sensation. If you're bitten by fire ants, you may see white, fluid-filled pustules or blisters (pictured) a day or two after the sting. These last three to eight days and may cause scars. The bumps may also be itchy and red, and you may have swelling around the site. It's important not to scratch or break open the blisters because they can become infected, notes the American College of Allergy, Asthma, and Immunology. Carpenter ant bites are also painful because they spray formic acid into the bite, which causes a burning feeling.
Mite and Chigger Bites Cause Intense Itching
Mites do not usually spread disease, but their bites can irritate the skin and cause intense itching. Itch mites usually feed on insects but will bite other animals, including people. The bites usually go unnoticed until itchy, red marks develop that may look like a skin rash.
Chiggers are a form of mite that inject their saliva so that they can liquefy and eat skin. In response to a chigger bite, the skin around the bite hardens. The surrounding skin becomes irritated and inflamed (pictured), and an itchy red welt develops.
Mites also cause the condition called scabies, which is contagious from person to person, notes the CDC. Female scabies mites burrow into the skin to lay eggs. When the eggs hatch, the larvae come to the skin's surface. They begin to molt and then burrow back into the skin to feed. This results in a skin rash that may look like acne pimples and create intense itching that gets worse at night. You may also notice light, thin lines on the skin where the mites have burrowed, including between the fingers, in the bends at the wrists and knees, and under jewelry on the wrists and fingers.
Kissing Bug Bites Can Pass On Disease-Causing Parasites
Kissing bugs, also known as assassin bugs, can pass on the parasites that cause Chagas disease. According to research from the University of Texas at El Paso published in October 2015 in the journal Acta Tropica more than half of these insects carry the parasite. In the United States, Chagas disease affects about 300,000 people, according to the CDC.
Kissing bugs hide in the daytime but emerge at night, often leaving bites on the face and causing a swollen eyelid. In the first few weeks after infection, symptoms of Chagas disease can include fever, fatigue, body aches, headache, rash, a loss of appetite, diarrhea, and vomiting. But, the CDC notes, in the long term, and even decades later, about 30 percent of people infected by kissing bugs will develop serious complications of Chagas disease: an enlarged heart, heart failure, abnormal heart rhythm, cardiac arrest, or an enlarged colon, also known as megacolon.
Hornet Stings Can Cause Serious Allergic Reactions
Hornet stings (like bee and wasp stings) are usually painful, itchy, red, and swollen immediately after they happen, without causing long-term effects. Many people can simply ice the area to soothe pain and pop an over-the-counter antihistamine (like Benadryl) to help with itching. “After a half hour, you can go on with your business,” says Howard Russell, an entomologist at the Center for Integrated Plant Systems at Michigan State University in East Lansing. Symptoms typically disappear after a day or two, says the Mayo Clinic.
However, if you’re allergic to bee, wasp, or hornet stings — or you’ve been stung multiple times — a sting can cause severe allergic reactions, including nausea, rapid heartbeat, swelling, dizziness, hives, and shortness of breath, warns the Mayo Clinic. Call 911 and seek emergency medical treatment if you experience any of these symptoms.
Hornets typically build their large paper nests in tree hollows, as well as undisturbed spots in barns, attics, and even walls, according to information from the University of Kentucky. Hornets will defend their nests (and may attack you) if you get too close, so leave the area if you do come across one. If you come across a solitary hornet, leave it alone; hornets typically only sting when threatened, the University of Kentucky notes. And if you do get stung, leave the area right away to avoid another attack, Russell says.
Certain Kinds of Flies Can Bite, Too
Although horse flies and deer flies most affect the animals in those names, unfortunately being a human doesn’t earn you a free pass. According to the University of Kentucky, these flies can both target humans who are outside, and the intensity of their attack varies from year to year. Bites can be painful and cause bleeding, swelling, irritation, or an allergic reaction. Swelling and irritation should disappear in a day or two.
The National Pest Management Association suggests wearing light-colored clothing and insect repellent as the most important strategies for prevention.
Black flies (sometimes called buffalo gnats or “no-see-ums”) are also common throughout the United States and can bite (though they’re not known to spread disease), according to Spokane Regional Health District. They’re small in size and usually bite around the head, particularly the eyes, ears, and scalp. Their bites can cause swelling, numbness, and soreness that can last for several days.
For all of these types of fly bites, they usually show up as small red bumps that are itchy.