5 Types of Fly Bites You Might Get —And How To Treat Them

Here's everything you need to know about itchy, sometimes-painful fly bites.

Wild garden small flying insect

Flies dive-bomb your face, march across your food, and can bite. Annoying? Sure. Painful? Sometimes.

According to the Environmental Protection Agency (EPA), flies are carriers and transmitters of numerous diseases due to breeding and feeding on animal waste, garbage, and human foods. They can carry bacteria and viruses that cause symptoms such as diarrhea and eye infections, among others.

But are fly bites dangerous? Rarely. However, their bites can hurt, and some people have more serious allergic reactions to their saliva.

Here are five common U.S. flies and what their bites can–and can't–do to you.

Horse Fly Bites

Horse flies received their common name because they are notorious pests of horses and other mammals, explains the National Pest Management Association (NPMA).

While horse flies are not known to be vectors of disease or capable of transmitting harmful disease-causing bacteria, they give painful bites that can cause allergic reactions.

According to the NPMA, horse flies are persistent and will continue to bite their host until they either succeed in procuring their blood meal or are killed. Female horse flies are even known to chase their intended targets for short periods. The NPMA suggests wearing light-colored clothing and insect repellant to help prevent bites from these unwanted visitors.

Sand Fly Bites

Sand fly bites can cause small red bumps and blisters that may itch and swell. Antiseptic and soothing lotions will help ease itching and prevent infections from developing.

According to the Centers for Disease Control and Prevention (CDC), in some cases, sand flies can transmit a parasitic disease, leishmaniasis. There are several different forms of leishmaniasis in people. The most common forms are cutaneous leishmaniasis, which causes skin sores that can change in size and appearance over time. They may start as bumps or lumps and end up as ulcers. The sores can be painful.

According to the CDC, almost all cases of leishmaniasis diagnosed in the U.S. have been in people who became infected while traveling or living in other countries, though occasional cases of cutaneous leishmaniasis have been acquired in Texas and Oklahoma.

U.S. troops in the Middle East often have trouble dealing with sand flies, said James Diaz, MD, professor, and director of the environmental and occupational health sciences program at Louisiana State University School of Public Health.

Deer Fly Bites

According to the United States Department of Agriculture (USDA), deer flies are the "premier daylight bloodsucker during the summer."

Larger than a house fly but smaller than a horse fly, deer flies are aggressive, and their bites (described as skin slashing) can be pretty painful. According to MIT Medical, the deer fly has a mouth with razor-sharp "lips," which it uses to slice the skin open, so it can feed on the resulting blood pool. As a result, their bites can be very painful. In addition, some people experience an allergic reaction to the salivary secretions released by the insects as they feed. Antihistamines, along with antiseptic and soothing lotions, are probably enough to tame their bites.

Deer flies only feed during the day, biting any exposed skin but prefer the head, so wear a hat. Common in the U.S., they prefer sunny places like lake edges, trails, and fields.

Deer flies also occasionally transmit tularemia, according to the CDC, or "rabbit fever," a bacterial infection usually treated with antibiotics.

Black Fly Bites

Black flies, sometimes called buffalo gnats, are very common in the U.S., according to the Entomology Department at Purdue University. Although they bite, they don't transmit diseases, at least not in America.

Black flies are small, hump-backed, and dark-colored, according to the USDA. They slash the skin to lap up blood. They will bite exposed skin and are especially skilled at getting under clothes. You might not notice a bite until you feel a small scab. Though some people will get a large, itchy welt that will last for days.

Some people react to a fly bite with a collection of symptoms known as "black fly fever," which can involve headache, nausea, fever, and swollen lymph nodes.

Black flies only feed during the day, so you can expect some relief after the sun sets. They appear in the late spring and early summer, especially along creeks and rivers.

Biting Midges or Gnat Bites

These pesky insects are a nuisance, particularly in hot and humid areas. According to the EPA, biting midges are small, gray, two-winged insects, less than 1/8" long. Often, you'll feel the bite (they hurt) without ever seeing the culprit—hence their "no-see-ums" nickname.

Biting midges are found throughout the United States but favor coastal areas, near farms, or in wet mud, mangrove swamps and salt marshes.

Midge or gnat bites look a lot like mosquito bites: small, red, itchy lumps or sometimes a red welt or blister. It's the female who bites, taking blood using an elongated jaw with small cutting teeth. Biting midges tend to deliver their trademark burning sting at dusk and dawn, though biting may continue throughout the night.

Biting midges are a known transmitter of Mansonella ozzaqrdi, a human nematode parasite.

Stable Fly Bites

Known also as dog flies, biting house flies, and power-mower flies, stable flies are globally recognized livestock pests. These blood feeders are pests of cattle and horses but will bite people and dogs, according to the University of Florida.

Certain regions of the U.S., such as coastal New Jersey, the Lake Superior and Lake Michigan shorelines, Tennessee Valley Authority lakes, and along the Florida panhandle coast west to Louisiana, are known for stable flies attacking people.

Stable flies typically bite in the early morning or late afternoon; they are most abundant in late summer and fall. They often attack the ankles, inflicting a sharp, stabbing pain, according to the Illinois Department of Public Health. Unlike many other blood-feeding insect bites on humans, the bite site does not appear to get irritated and bites rarely result in allergic reactions, as per the University of Florida.

Fly Bite Treatment

According to the American Academy of Dermatology (AAD), fly bites, like most bug bites, can be safely treated at home with topical medication, such as hydrocortisone cream or ointment, or an oral antihistamine to reduce the itch.

However, sometimes a bug bite or sting could turn into something serious—especially if you are allergic to the saliva or venom or if the bug is carrying a disease. You should see your healthcare provider if you experience fever, swelling, or increasing pain following an insect bite.

According to the AAD, you should go to the emergency room immediately if you experience any of the following symptoms after a bug bite or sting: Difficulty breathing; the sensation that your throat is closing; swollen lips, tongue, or face; chest pain; a racing heartbeat that lasts more than a few minutes; dizziness; vomiting; headache.

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