Most fly bites aren’t serious, causing pain or itching that you can resolve with medications or natural treatments. But some flies can spread illnesses that require a doctor’s attention.

Flies are an annoying yet inevitable part of life. One pesky fly buzzing around your head can throw off an otherwise lovely summer day. Most people have been bitten by a fly at least once in their lifetime. In most cases, it’s nothing more than irritating.

According to the University of California Museum of Paleontology, there are about 120,000 species of fly throughout the world, and many of them bite animals and people for their blood. Some species carry diseases, which they can transmit to humans thorough bites.

Sand flies are about 1/8 of an inch long, and have hairy, brownish-gray wings. They hold their wings above their bodies in a “V” shape and are most active between dusk and dawn. The larvae look like worms.

They’re found mainly in tropical and subtropical climates. They breed in places with a lot of moisture, such as decaying plants, moss, and mud. In the United States they’re mostly found in the southern states.

Sand flies eat nectar and sap, but females also feed on the blood of animals and humans.


In general, sand fly bites are painful and may cause red bumps and blisters. These bumps and blisters can become infected or cause skin inflammation, or dermatitis.

Sand flies transmit diseases to animals and humans, including a parasitic disease called leishmaniasis. According to the Centers for Disease Control and Prevention (CDC), leishmaniasis is rare in the United States. You may contract it during travel to a foreign country. There are no vaccinations to prevent leishmaniasis. Symptoms include skin sores weeks or months after the bite. They often clear up without treatment, but can be serious in some cases.


You can apply hydrocortisone or calamine lotion directly to the bites to help them heal and reduce itching. Oatmeal baths and aloe vera can also soothe itching. For persistent sores or ulcers, you should see a doctor.

The bloodsucking tsetse fly is about 6 to 15 millimeters long and its mouth points forward. It makes its home in the tropics of Africa, and prefers shady places in wooded areas. It hides in tree trunk holes and between tree roots.


The tsetse fly bite is often painful and can cause red bumps or small red ulcers at the site of the bite. It can also transmit sleeping sickness (trypanosomiasis) to animals and humans.

Trypanosomiasis is generally not found in the United States except in people who have traveled to Africa. Early symptoms include headache, fever, and muscle aches. Later, you may experience mental confusion or coma. Trypanosomiasis causes swelling in the brain and is fatal, if untreated.


If you’ve been bitten by a tsetse fly, your doctor can run simple blood tests for sleeping sickness.

Antitrypanosomal medications, such as pentamidine, are highly effective in treating sleeping sickness.

Deer flies are about 1/4 to 1/2 of an inch long, with brownish-black bands on their otherwise transparent wings. They may have gold or green eyes on their small, rounded heads.

They are most active during spring and like to be near lakes, swamps, or other bodies of water. The larvae resemble maggots.


Deer fly bites are painful, and will cause red bumps or welts. They transmit a rare bacterial disease known as rabbit fever (tularemia). Symptoms include skin ulcers, fever, and headache. Tularemia can be successfully treated with antibiotics, but without treatment, it can be fatal.


To treat deer fly bites, clean the affected area with soap and water. You can apply ice to the area to treat pain. You can also take allergy medicine like diphenhydramine (Benadryl) to reduce itching, which can prevent secondary infection.

Black flies are small, ranging from 5 to 15 millimeters as adults. They have an arched thoracic region, short antennae, and wings that are large and fan-shaped. They are often found near bodies of water where their larvae grow.

Black flies can be found throughout most of the United States, but their bites do not appear to transmit diseases here. In other regions of the world, including Africa and South America, their bites can transmit a disease called “river blindness.”


Black flies typically bite near the head or face. Their bites leave a small puncture wound, and can result in anything from slight swelling to a swollen bump the size of a golf ball. Other symptoms can include headache, nausea, fever, and swollen lymph nodes. When these symptoms occur, they’re referred to as “black fly fever.”


Apply ice to the area for fifteen minute intervals to reduce swelling from a black fly bite. You can apply cortisone or prescription topical steroids to the affected area. Washing the area with soap and water can reduce the risk of infection.

Biting midges are extremely small at only 1 to 3 millimeters in length. The adults can be reddish after they’ve eaten, or gray when they haven’t. The larvae, which are white, can only be seen with a microscope.


Bites from biting midges resemble small red welts. They can be found all over North America. The bites are persistently itchy, and many people with bites feel like something is biting them but they can’t see what.

In other parts of the world, biting midges can transmit filarial worms to humans, which live inside the skin. This can result in dermatitis and skin lesions.


Avoid scratching the bites of biting midges. Treatment with cortisone or prescription topical steroids can help. For natural remedies, you can apply aloe vera topically.

Stable flies strongly resemble the standard house fly, but are slightly smaller in size at 5 to 7 millimeters. They have seven circular black spots in a checkerboard pattern on their abdomen.

Stable flies can be found all over the world, and are particularly prevalent around livestock. In the United States in areas like New Jersey, Lake Michigan shorelines, the Tennessee Valley, and the Florida panhandle, the flies are most likely to bite humans.


Stable fly bites often feel like sharp needle pricks, and occur most often on the feet, ankles, behind the knees, and legs. Red rashes and small, raised red bumps are common at the bite mark.


You can take medications like Benadryl to reduce itching and swelling and apply ice to the bite mark to reduce pain. Benadryl can also reduce hives caused from the bite.

Preventing fly bites is much easier and less painful than having to treat them. You can’t avoid flies entirely, but you can make your yard less inviting by keeping grass and plants well-trimmed.

Talk to your doctor if you plan on visiting a foreign country. You may need vaccines or medication prior to your trip. Also see your doctor if you experience fever, swelling, or increasing pain following an insect bite.