Published June 30, 2026 01:11 pm
Hiking or going on an outdoor adventure can leave you feeling well-tired, at peace, and connected to nature. But you may also end up with a less pleasant souvenir: a nasty bug bite—or their extermination.
Figuring out which one bit you can help determine what kind of itching or pain you can expect and whether you need to worry about any insect-borne illness.
“Everyone’s reaction to insect bites is slightly different, so it’s not always possible to know the culprit just by looking at the bite,” Alison GardnerMedical entomologist and associate professor of arthropod vector biology at the University of Maine explains Outside. That said, there are clues in how the bites feel, as well as where and how they grow, that point toward one bug versus another.
Read on for a guide to common outdoor-related bug bites, including their infection risk level on a scale of 1 to 3 (1 being harmless and 3 being serious in terms of potential disease transmission and infection risk), as well as how to reduce the risk of illness and find relief.
1. Mosquito
infection risk level: 1
When a mosquito pierces your skin to draw blood, “it effectively injects a numbing agent, so you don’t even notice its presence,” says Gardner. She adds that an itchy, swollen lump usually appears after a few hours.
“People with Skeeter syndrome have an exaggerated allergic reaction to these bites, so the lumps may become larger, more raised, and intensely itchy,” Dr. Morgan GohenA physician scientist who studies mosquitoes and infectious diseases at Yale School of Medicine explains Outside.
Centers for Disease Control and Prevention Most mosquitoes in the US are labeled as “nuisance mosquitoes” because, while annoying, they generally do not spread diseases. However, some mosquitoes that are known to spread diseases like Zika, dengue and chikungunya have been identified in parts of the Southern US, Goheen says, so be sure to see a doctor if you experience flu-like symptoms after being bitten.
2. Lone Star Tick
Infection risk level: 3
if you get bitten Any Gardner says you’ll probably be able to spot a tick by the site of the bite while hiking. If you do not remove them, these insects remain there for hours and even days. Gardner says the reddish-brown Lone Star tick gets its name from the white spot on the back of adult females. (The male has brown stripes on his sides.)
Lone Star ticks can transmit certain diseases – such as ehrlichiosis, Heartland virus and Southern tick-associated rash disease (STARI) – and are notorious for triggering alpha-gal syndrome, which causes a severe allergy to red meat. It is best to remove the tick as soon as possible; Gohain says the longer it remains attached, the more likely it is that it will pass along the pathogen. Use tweezers to hold it close to your skin and pull straight up.
Be alert for symptoms that require medical care, such as fever, vomiting, and muscle or joint pain. With STARI, you may develop a bullseye-shaped rash at the site of the bite; Others generally do not have skin symptoms, but ehrlichiosis may cause a blotchy or pinpoint rash.
3. American Dog Tick
Infection risk level: 3
Even with these ticks, you are bound to recognize the insect rather than being bitten. Gardner says dog ticks are brown and have white stripes or a spotted white pattern on their backs. It is important to uproot them as soon as possible because they can spread bacterial infections such as Rocky Mountain Spotted Fever (RMSF) and tularemia.
RMSF starts with flu-like symptoms and progresses to small purple spots on the hands and feet that spread to your torso, says Gohain. Tularemia usually causes chills, fever, and swollen lymph nodes. If you notice any of these symptoms after a tick bite, you should seek medical attention.
4. Black-legged tick (aka deer tick)
Infection risk level: 3
Gardner says that if a black-legged tick bites you while out on a hike, you’ll likely catch it with its black legs hanging out of you — that’s its defining characteristic. These are the ticks that can spread Lyme disease.
One way to tell if you have Lyme is the hallmark bullseye-shaped rash (which, unlike STARI, can occur in multiple locations on the body). But also be careful: That rash can take up to 30 days to develop after a bite and may never occur in some people with Lyme, who may still experience joint pain, fever, and other flu-like symptoms, Gardner says.
Black-legged ticks can transmit babesiosis (a disease caused by a parasite that attacks red blood cells) and anaplasmosis (a bacterial disease that usually occurs in early summer or late autumn), among other diseases, so it is important to remove them swiftly and seek medical care if you experience fever, nausea, pain, fatigue or any other flu-like symptoms in the month following the bite.
5. Horse flies
Infection risk level: 2
Chances are, you’ll see and feel one of these large—up to an inch long—bloodsucking flies when it bites you. Gardner says that unlike mosquitoes, their mouthparts work like pincers, tearing the skin rather than piercing it. She explains that it’s immediately painful, like a bee sting, and you may start bleeding before a tender, raised welt forms near the bite site.
Although these bites can really hurt, they will not put you at risk for disease, as horse flies do not generally carry disease. However, if your skin does break, it is important to wash the area with warm soapy water (or wipe it with an alcohol wipe) to prevent it from becoming infected with bacteria on your skin. Dr. Shannon DowlerThe North Carolina-based family physician and member of the board of directors of the American Academy of Family Physicians explains Outside.
6. Deer Flies
Infection risk level: 1
Deer fly bites will appear very similar to horse fly bites – generally a larger, more swollen lesion than a mosquito bite that hurts immediately or stings more than itches. Gardner explains that deer flies and horse flies are in the same family and bite in similar ways. Deer flies are about half the size of horse flies and may be more likely to bite your face, other parts of your head, and shoulders.
The bite site may bleed (be sure to disinfect it if so), and the area around it may be swollen and tender, but like horse fly bites, the risk of disease from deer fly bites is very low.
7. Black flies
Infection risk level: 2
Gardner says bites from blackflies, aka buffalo mosquitoes, are similar to mosquito bites in that they typically create a red, itchy rash. But these flies feed like deer flies and horse flies, so you may feel them when they bite you — it may just be a prick versus full-on pain because they’re smaller in size, Gardner says. It is common to have multiple black fly bites at once, and they can become extremely itchy over time.
The good news is that black flies in the US do not spread infectious disease to humans but some people may develop a collection of symptoms called “.black fly fever,” an allergic reaction to the saliva of flies that includes fever, nausea, and swollen lymph nodes. If these symptoms occur, see a doctor.
8. Chiggers
Infection risk level: 1
there is common myth That these microscopic mite larvae penetrate the skin – but in reality, they stick around temporarily, use an enzyme to liquefy and consume skin cells, and then fall off. The intensely itchy rash is a reaction to residual enzymes when they occur.
Gardner says bite marks can look like clusters of small red dots or hives that can turn into blisters, and they usually occur on the ankles and in skin folds, such as behind the knees or where clothing is tightly bound to the body, such as the waist. Chiggers have not been found to spread disease to people in the US, so their bites do not pose a long-term threat.
9. Flea
Infection risk level: 2
The same insects you might associate with your pet can also feed on human blood, leaving behind small red or discolored rashes that usually occur in groups or rows of three, called “.breakfast, lunch and dinner signs” These wingless insects do not fly but rather jump on people and pets, so their bites often occur on the lower legs and ankles. They resemble small mosquito bites, itch a lot, and may blister.
While flea-borne diseases are rare in the US, these insects can spread bacteria such as typhus (which can be treated with antibiotics) and plague. These illnesses may manifest with fever, chills, nausea, and weakness, among other symptoms, and require immediate medical care.
10. No-See-Ums
Infection risk level: 1
These blood-sucking flies are small (hence their name) but like their larger fly counterparts, they bite the skin, instantly creating painful, itchy wounds. Also known as biting midges or sand flies, no-see-ums typically swarm around the ankles, back of the neck, and other exposed areas, and leave behind random clusters of bites. Although cases of oreopouche virus (a flu-like illness) have been linked to no-see-ums in South and Central America, they are not known to spread disease in the US.
What to do when you notice insect bites or rashes after being outside
If it is a tick bite, it is important to remove the insect and monitor for flu-like symptoms. If the blacklegged tick continues feeding for a long time (several hours), see your doctor. They may recommend a prophylactic dose of doxycycline to prevent Lyme disease, says Gohain.
For other bites, do your best to avoid aggressive scratching, which can bring bacteria from your skin or nails to the bite site and cause infection, says Dowler.
And be sure to treat any symptoms, says Dowler. If you’re itching, she recommends applying a cool compress. Over-the-counter (OTC) topical steroid creams like hydrocortisone can be soothing, she says, and if the welts are very swollen, an OTC antihistamine (e.g., Benadryl or Zyrtec) can reduce the severity of the reaction. Soothing agents like calamine lotion or aloe vera can also reduce itching, and if pain is a problem, she says, acetaminophen or ibuprofen are your best options.
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