When Should You Go to the Doctor for a Horse Fly Bite?

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When Should You Go to the Doctor for a Horse Fly Bite?

Key Takeaways:

  • Most horse fly bites will heal on their own with basic first aid like cleaning and icing the area.
  • Seek medical care if the bite shows signs of infection like pus, swelling, redness, warmth or you have flu-like symptoms.
  • Allergic reactions with symptoms like trouble breathing, hives or dizziness warrant an urgent doctor’s visit.
  • People with weakened immune systems should have any horse fly bite evaluated by a doctor.
  • Pain that worsens over time rather than improving needs medical assessment to rule out complications.


Horse flies are large, aggressive flies that can deliver a very painful bite when they feed on human or animal blood. Their sharp, knife-like mouthparts pierce the skin and saw back and forth as they extract blood. This causes extensive tissue trauma and the bites often continue oozing blood even after the fly leaves. Understandably, horse fly bites hurt far more than typical mosquito or blackfly bites. The good news is that most horse fly bites resolve without medical intervention. With proper first aid and bite care at home, you can expect the bite to heal within a week or so. However, some people can experience excessive inflammation, infection or allergic reactions from horse fly bites. Knowing when to seek medical attention for a horse fly bite is important, especially if you develop any concerning symptoms.

This comprehensive guide will outline when it is advisable to have a medical professional evaluate and treat a horse fly bite. We will cover basic first aid steps you can take at home first for typical bites. Symptoms and situations that warrant a trip to the urgent care clinic or doctor’s office will also be explained. With the right information, you can monitor horse fly bites and know when self-care is adequate versus seeking medical assessment and care.

How to Treat a Horse Fly Bite at Home

Most horse fly bites can be managed effectively at home with self-care. Here are some first aid steps you can take immediately after being bitten:

When Should You Go to the Doctor for a Horse Fly Bite?
  • Clean the bite area – Use soap and water or an antiseptic spray to clean the bite and surrounding skin. This helps remove any saliva or potential pathogens left behind that could cause infection.
  • Apply an ice pack – Icing the bite brings down swelling and inflammation. It also helps ease the pain and itchiness. Apply an ice pack wrapped in cloth for 10-15 minutes a few times a day.
  • Try a paste of baking soda and water – Make a thick paste of baking soda and water and apply it to the bite. Let it dry on the skin. This can draw out toxins from the bite and relieve itchiness.
  • Consider over-the-counter medications – Antihistamines like Benadryl can reduce allergic reactions and itching. Ibuprofen or acetaminophen helps relieve pain and inflammation. Always follow dosage guidelines.
  • Elevate the bitten limb – If the bite is on your leg or arm, keep it elevated on a pillow when possible to reduce swelling.
  • Avoid scratching the bite – This can break the skin and introduce bacteria leading to infection. Apply creams or cold packs instead for itch relief.

When to See Your Doctor for a Horse Fly Bite?

Most horse fly bites start healing within a few days up to a week with proper first aid. However, they can occasionally cause infections or allergic reactions that require medical treatment. See your doctor or visit urgent care for evaluation if:

Is the bite showing signs of infection?

Symptoms may include:

  • Pus or oozing discharge – Yellow or green fluid draining from the bite marks
  • Increasing warmth and redness – The bite looks more inflamed and feels warm to touch
  • Streaking redness – Red streaks spreading out from the bite site
  • Swollen lymph nodes – Swollen or tender lymph nodes near the bite
  • Fever and chills – Flu-like symptoms pointing to infection

If an infected horse fly bite is not treated with antibiotics, the infection can spread deeper into the skin and underlying tissues. This requires more extensive treatment.

Is the bite causing an allergic reaction?

Watch for these allergy symptoms:

  • Hives or rash – Red, raised itchy rash near the bite or beyond
  • Difficulty breathing – Wheezing, tightness in chest, coughing spells
  • Swelling of face/lips – Signs of anaphylaxis
  • Dizziness, fainting – Drop in blood pressure from allergic response
  • Nausea, vomiting – Allergy symptoms affecting the gut

Allergic reactions need immediate medical care with epinephrine, steroids, antihistamines and fluid support to prevent dangerous anaphylaxis.

Is the pain getting worse instead of better?

The pain from a horse fly bite normally peaks in the first 24-48 hours. It then gradually improves with first aid and home care. Worsening pain can signal:

  • Infection – The bite area is becoming more inflamed and tender
  • Abscess – Pus building up under the bite site
  • Cellulitis – Deep tissue inflammation and swelling

Pain that continues to intensify warrants medical assessment to rule out potential complications.

Do you have a weakened immune system?

People with weakened immunity, such as:

  • Cancer patients on chemotherapy
  • Transplant patients taking immunosuppressants
  • Those with HIV/AIDS
  • Patients on steroids long-term

Are at higher risk of developing infections from insect bites. It is generally recommended to have any horse fly bite evaluated promptly by a doctor to get preventive antibiotics if required.

Are there signs of a severe reaction?

Severe allergic reactions to horse fly bites are rare but can develop, sometimes even in those who have tolerated bites well in the past. Seek emergency care if you have symptoms like:

  • Difficulty breathing, speaking
  • Lightheadedness, confusion
  • Rapid heart rate, low blood pressure
  • Nausea, vomiting or diarrhea
  • Swelling in the throat

These are signs of an advancing allergic response and potentially life-threatening anaphylaxis. Call 911 and get to an emergency room immediately.

Doctor’s Evaluation of a Horse Fly Bite

When you visit the doctor with concerns over a horse fly bite, your physician is likely to:

  • Ask about your symptoms – Pain levels, swelling, discharge, spread of redness, itchiness will all be reviewed.
  • Check for signs of infection – Examine the bite for pus, reddening, swollen lymph nodes and measure body temperature.
  • Evaluate allergic responses – Assess for hives, rash, difficulty breathing and other allergy indicators.
  • Consider underlying conditions – Chronic illnesses, medications, immune status will be noted.
  • Discuss timing and location of bite – When were you bitten, where on the body, and have you traveled recently?
  • Order diagnostic testing if needed – Blood tests, cultures, X-ray or MRI for severe infections

Horse Fly Bite Treatment Options

Depending on the evaluation, the doctor may suggest:


  • Antibiotics – For bacterial infection of the wound
  • Oral steroids – For reducing inflammation and allergic reaction
  • Epinephrine – For anaphylaxis or severe allergic response
  • Antihistamines – To relieve itching and mild allergic reaction
  • NSAIDs – Anti-inflammatories to ease swelling and pain

Wound Care

  • Incision and drainage – Of bite abscesses to release trapped pus
  • Wound cleaning – Removal of dirt, debris and discharge
  • Wet-dry dressings – To help drain purulent wounds
  • Topical antibiotic ointment – When infection is superficial
  • Tetanus immunization – If vaccination status is not up to date

Other Interventions

  • Skin testing – To identify specific allergen triggers for severe reactions
  • Referral to allergy specialist – For recurrent anaphylactic reactions to bites
  • Intravenous fluids – To stabilize blood pressure in shock from allergic response
  • Hospitalization – For severe infections requiring intravenous antibiotics

Your doctor will tailor their treatment recommendations based on the severity of your symptoms, extent of infection, presence of allergic response and other specific factors. Follow your doctor’s advice and take the full course of any prescribed antibiotics or medications. Call your physician promptly if symptoms are not improving on treatment or you develop any concerns about the bite. Avoid future horse fly bites by using insect repellent when outdoors and wearing long sleeves and pants. See your doctor whenever a bite leads to unusual swelling, severe pain or other concerning symptoms to prevent complications.

Frequently Asked Questions (FAQs) About Seeing a Doctor for a Horse Fly Bite

How soon after a horse fly bite do you need to see a doctor?

You should see a doctor promptly, within 24 hours, if the horse fly bite shows signs of infection like pus, worsening pain or flu symptoms. Allergic reactions with breathing difficulty or widespread hives also warrant urgent medical care.

When should you go to the ER for a horse fly bite?

Seek emergency care if you develop signs of a severe allergic reaction such as trouble breathing, dizziness, swelling of the face and throat, nausea or a racing heart rate. Anaphylaxis is a medical emergency needing immediate treatment with epinephrine.

Can you get blood poisoning from a horse fly bite?

Yes, horseflies can transmit bacteria through their bite leading to blood poisoning or bloodstream infections. See a doctor right away if the bite area shows streaking redness along the veins or you develop fever, chills and muscle pains.

What should you not do for a horse fly bite?

Don’t scratch or further irritate the bite as this can worsen swelling and itchiness. Avoid home remedies like essential oils, vinegar or bleach which can damage skin. Don’t wait to see if symptoms go away – seek medical attention if signs of infection develop.

When do horse fly bites start to heal?

With proper first aid, most horse fly bites begin healing within 3-5 days. The severity of pain and inflammation reduces steadily when healing progresses normally. If the bite has not started improving within a week, see your doctor.

Can horse fly bites cause lymph nodes to swell?

Yes, nearby lymph nodes can swell and become tender within a day or two of a horse fly bite as your body fights off bacteria transmitted by the fly. However, seek medical care if the swollen nodes do not go down after 5-6 days.

Do horse fly bites blister?

It is uncommon but horse fly bites may develop small, fluid-filled blisters at the bite site as the skin reacts to the fly’s saliva. Typically no treatment is needed but avoid bursting these blisters which can lead to infection.

How do you treat an infected horse fly bite at home?

Use warm compresses on infected bites to draw out pus. Apply antibiotic ointment 2-3 times a day after cleaning the area thoroughly with soap and water. Take oral antibiotics if prescribed by your doctor. However, see your physician if home remedies do not resolve infection.

When should you get a tetanus shot after a horse fly bite?

Most people only need a tetanus immunization if it has been over 10 years since their last tetanus vaccine. However, if you have never gotten tetanus vaccine or have a deep, contaminated bite, your doctor may advise a shot within 48 hours of the bite.

In summary, most horse fly bites can be treated with first aid and home remedies. However, call your doctor promptly or visit urgent care if the bite appears infected or you have concerning symptoms. Getting medical care prevents complications and helps resolve horse fly bites that are slow to heal or cause excessive inflammation

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