What to Do About a Horsefly Bite

Horseflies come from the Tabanidae family of insects, which also includes deerflies. These large, blood-sucking flies have strong mandibles that resemble scissors or blades and contain small “hooks" that cut into your skin. This makes horsefly bites surprisingly painful in comparison to many other bug bites.

While horsefly bites are painful and itchy, they’re usually not dangerous. In rare cases, a person may have an allergic reaction and need immediate medical attention. This article explains what you can do about the bite and when you need to reach out to a healthcare provider.

What Does a Horsefly Bite Look Like?

Horseflies are typically between one-half inch and a little over 1 inch long. They tend to have black or gray bodies, short antennae, large heads, and large green eyes. 

Horsefly bites usually look like large, swollen welts around a central point. They tend to be red or discolored, irritated, and itchy. Female horseflies are aggressive and may bite more than once, so you may have multiple skin lesions.

Is a Horsefly Bite Dangerous?

Horsefly bites might seem scary because they can be so painful and itchy, but they typically aren’t dangerous. Your swelling and other symptoms should go down on their own after a few days. 

In rare cases, horsefly bites can lead to the following health complications:

• Skin reactions: Some people experience localized skin reactions after a horsefly bite, such as persistent inflammation and swelling.
• Bacterial infections: The affected area of your skin could get infected, especially if you’re frequently scratching or picking at it. 
• Tularemia: It’s possible to get tularemia, a type of bacterial infection that can be passed on to humans through contact with an infected animal or insect, after a horsefly bite. Symptoms, which begin after around three to five days, include fever, conjunctivitis (pink eye), headache, unexplained weight loss, difficulty breathing, pain, stiffness, and skin ulcers. Tularemia can be severe or even fatal. It’s treated with antibiotics. 
• Anaphylaxis: It’s possible to have a severe allergic reaction after a horsefly bite. This requires emergency medical treatment.

When Do Horsefly Bites Typically Happen?

Horseflies are drawn to heat and sunlight. This makes them more likely to bite in bright, sunlit areas during the hot summer months. 

Horsefly bites are also especially common near bodies of water and in areas where there are many wild or domesticated animals. This is because they often bite other warm-blooded mammals, such as horses, cattle, and dogs, in addition to humans.

What You Can Do for a Horsefly Bite at Home

If you’ve been bitten by a horsefly, you can relieve your pain, discomfort, and itching by:

• Disinfecting the area with soap and water 
• Applying a cold compress, such as ice wrapped in a washcloth, to the affected area for around 10 minutes at a time
• Taking antihistamines or applying antihistamine cream to the bite to relieve itching
• Taking over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs), such as Advil or Motrin (ibuprofen), for pain relief
• Applying antibacterial ointment, such as Neosporin (neomycin, bacitracin, and polymyxin) to the skin to prevent infection
  

When to Contact a Healthcare Provider

Most horsefly bites can be resolved on their own at home. However, you should contact a healthcare provider if:

• Severe swelling in the affected area
• Symptoms that persist or get worse over the following days
• Signs of a bacterial infection, such as fever, pus, or skin that is warm to the touch 
• Any symptoms of an allergic reaction

Your healthcare provider may prescribe additional treatments, such as antibiotics or topical corticosteroids, to relieve the above symptoms.

Call 911 or go to the hospital for emergency treatment if you have any signs of anaphylaxis (a severe allergic reaction) after a horsefly bite, such as:

• Difficulty breathing or swallowing
• Dizziness
• Confusion
• Swelling in the tongue, face, throat, lips, mouth, or eyes
• Muscle weakness
• Pale, cool, and/or blue skin
  

How to Prevent Horsefly Bites

You can prevent many horsefly bites by:

• Using insect repellent when you go outdoors
• Wearing protective clothing 
• Wearing lighter clothing, as horseflies are drawn to dark, shiny targets
• Staying in cool, shady areas during the summer months
• Avoiding contact with wild or farm animals, or wearing protective gear if it’s necessary

Summary

Horsefly bites can be very painful, but they don’t tend to cause serious health complications. If you’ve been bitten by a horsefly, disinfect the affected area and monitor it for signs of infection in the following days.

If your symptoms persist, or if you notice any symptoms of anaphylaxis, such as light-headedness or severe swelling, reach out to a healthcare provider immediately.