How to Identify Common Bites and Stings
Getting bitten by a bug 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 bites and stings from common insects are harmless and heal quickly. But some bites and stings, like those from fire ants, wasps, hornets, and bees, may cause intense pain or even an 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. Tick bites can carry Lyme disease with a rash that looks like a bull’s-eye. Most bug bites are transmitted directly from the insect, and most bug bites 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.
The best way to prevent insect bites is to avoid insects, wear protective clothing, use pesticide, not eat foods or wear fragrances that attract bugs, and know your own personal risk for having an allergic reaction to a bug bite.
Because certain bites can also spread illnesses such as the Zika virus and West Nile virus (both transmitted by mosquito), Lyme disease (from a black-legged tick), Rocky Mountain spotted fever (from a dog or wood tick), or Chagas disease (from kissing bugs), it's good to know what bit you. Learning to identify a bug bite by how it looks and feels will help you know whether to seek medical care or treat the skin bump at home.
A mosquito bite appears as an itchy round, red, or pink skin bump. It's usually harmless but can sometimes cause a serious illness, such as the Zika virus (particularly harmful in pregnant women), the West Nile virus, or malaria. For most people, Zika causes a brief, flu-like illness. But pregnant women with Zika infection have had an alarming increase in microcephaly birth defects in their newborns — a debilitatingly small head and brain size. The Centers for Disease Control and Prevention (CDC) posted a 2016 travel alert advising pregnant women to delay travel to 50 areas where Zika is active including Latin America and the Caribbean.
About 2,000 U.S. cases of the West Nile virus were reported to the CDC in 2014. 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 occurence in the United States, with only about 1,500 cases reported by the CDC each year. Symptoms are similar to the flu and can include fever, headache, muscle aches, nausea, and vomiting from 10 days to 4 weeks after the bite. Malaria is serious, but it's good to know it is preventable and treatable, according to the CDC.
Bed Bug Bites
You probably won't feel pain when a bed bug bites, but you may see a row of two or more red marks on your skin. Some people develop a mild or severe allergic reaction to the bug's saliva between 24 hours and three days later. This can result in a raised, red skin bump or welt that's intensely itchy and inflamed for several days. This can also include hives, and may mean a trip to your healthcare provider for treatment, notes the American Academy of Dermatology. Bed bug 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, bed bugs do not carry disease, according to the CDC.
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
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.
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 NIH National Library of Medicine. Be sure to seek medical attention immediately if you could have been bitten by a poisonous spider, by calling 911 or the American Association of Poison Control Centers at 800-222-1222.
Some tick bites can be dangerous because they 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 later, when Lyme disease is in its advanced stages. A diagnosis may remain elusive because many doctors will not equate these symptoms with Lyme disease.
Rocky Mountain spotted fever from a tick bite is rare, with about 2,500 U.S. cases per year. It causes a fever, headache, muscle aches, and a skin rash. The rash 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.
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 more common on your ankles, 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, the bites of fleas infected with the bacteria that causes plague can spread the disease from wild rodents to pets and to people. Over the past 10 years, as few as one, 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 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. If you have this type of allergic response, called anaphylaxis, it is a medical emergency that needs treatment immediately. Symptoms of severe allergy to a bee sting include hives, swelling, trouble breathing, dizziness, cramps, nausea, diarrhea, and even cardiac arrest.
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, and will need to be treated by a doctor, but lice are not known to carry other diseases.
Ant Bites and Stings
Ant bites and stings are typically painful and cause red skin bumps. Some types of ants, like fire ants, are venomous and can cause a severe allergy. 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 above) a day or two after the sting that 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 the blisters open, because they can become infected, notes the American College of Allergy, Asthma, and Immunology. Carpenter ants bites are also painful because they spray formic acid into the bite, which causes a burning feeling.
Mite and Chigger Bites
Mite bites do not usually spread disease, but they 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 the chigger bite, the skin around the bite hardens. As the picture above illustrates, the surrounding skin becomes irritated and inflamed, 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 surface, begin to molt, and 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.
Dr. James L. Castner/Corbis
Kissing Bug Bites
Kissing bugs, also known as assassin bugs, can pass on the parasites that cause Chagas disease. According to September 2015 research from the University of Texas at El Paso published in 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 in the long term, and even decades later, the CDC notes that 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.
- Last Updated: 06/05/17
- Last Updated: 06/05/17