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Ticks aren’t the only external parasites that feed on our canine companions. Black flies also suck dogs’ blood, leaving behind a bullseye-like rash on the feed site. Don’t worry, there’s good news: black flies are nothing more than a common nuisance, and they don’t spread life-threatening diseases like ticks do.

Most of the time, black fly bites resolve on their own within a few days, causing nothing more than minor skin irritation and itching. Still, some circumstances may call for a veterinarian’s insight. If the lesion seems infected (or is located near the dog’s eyes or mouth), consult your dog’s healthcare team.

Black Fly Bites Are Usually Not Cause for Concern

Dr. Jerry Klein, the American Kennel Club’s Chief Veterinarian, shares that while black fly bites are inconvenient, they’re usually not an immediate threat to dogs’ health.

“Black flies (or buffalo gnats) cause bite wounds on dogs that are large, red, or bruised, [and] more easily seen on lightly coated areas, such as their underside,” Dr. Klein explains. “Some of the wounds may have a pale center giving the impression of a ‘bullseye’ appearance similar when humans get bitten by a tick having Lyme disease.”

When a dog develops Lyme disease, symptoms may include joint swelling, generalized stiffness, and lameness. They will not develop a target-like rash, which is a human-specific symptom. It’s recommended to get your dog vaccinated against Lyme disease and other transmissible illnesses.

German Shepherd Dog getting a shot at the vet.
V&P Photo Studio

Recognizing Black Fly Bites on Dogs

Black flies are common throughout the United States, but they’re especially prevalent near bodies of water in the late spring and early summer. As bloodsucking parasites, they may feed on your dog’s blood during a swim, playing a game of fetch, or tending to nature’s call. The bites themselves don’t hurt, but they can itch. So, your dog may lick or bite the wound.

Over time, this could lead to open sores, infection, and other complications that require veterinary care. As we’ll discuss later, you can prevent the over-licking of black fly sores using a collar or topical creams.

Black Fly Bites vs. Tick Bites: What to Know

There are key differences between black fly and tick bites.

  • Ticks don’t feed in swarms, but black flies do. You may notice multiple fly bites on your dog, as opposed to one tick bite.
  • Black flies can land and feed on a dog within seconds. A tick must attach itself to the dog to draw blood, and this can take anywhere from a few minutes to a few hours.
  • Once a tick has latched on to your dog, you must remove it using tweezers. A black fly will leave on its own.

Black Fly Bites vs. Ringworm on Dogs

Despite the name, ringworm isn’t an internal parasite like tapeworms, hookworms, and whipworms. Rather, it’s a fungus that grows on the skin’s outermost layer and in a dog’s hair follicles. Dogs generally get the condition through contact with an infected surface, such as a communal food bowl.

Australian Cattle Dog puppies drinking from a bowl in the yard.
©OlgaOvcharenko - stock.adobe.com

The main difference between a black fly bite and ringworm is the texture of the wound’s outermost circle. A black fly bite is flat and will only become inflamed if infected. Standard ringworm feels slightly elevated to the touch, and it may also be scaly.

Another difference is the number of wounds. Ringworm presents as a solitary, inflamed red ring, usually on the face, tail, ear tips, or feet. Black fly bites occur in clusters in nearly hairless areas, like on a dog’s underbelly.

How to Treat Black Fly Bites on Dogs

As noted, most black fly bites heal within a matter of days. Still, you may wonder how you can encourage the healing process.

Dr. Klein suggests, “Keep the area clean by washing the area with cool, mild soapy water, application of ice compress, [and] administration of antihistamines (if directed by your veterinarian). Creams containing antihistamine and or hydrocortisone can be helpful when lightly applied, providing one closely monitors your dog, so it does not lick the ointment off for at least 15 minutes.”

If your dog insists on biting or licking the affected area, your veterinarian may suggest getting a protective collar to limit their range of motion. How long your dog must wear the collar depends on the fly bite’s location, size, and whether it’s infected.

How to Prevent Black Fly Bites on Dogs

While black flies are found throughout the country, they’re particularly dense in humid, subtropical regions, such as the American South. They lay eggs in rivers, ponds, and streams, and will remain close to the shore throughout their three-to-four-week lifespan. Avoiding these areas can prevent black fly bites on your dog.

mayalain/Getty Images Plus

Other preventative measures include:

  • Planning outings during certain parts of the day. Black fly swarms are the greatest a few hours after sunrise and a few hours before sunset. There’s a “sweet spot” when it comes to enjoying the outdoors with your dog while avoiding black fly swarms.
  • Utilizing protective clothing. Black flies may target dogs with thin fur and exposed underbellies, such as Italian Greyhounds. A coat or jacket may cover up these areas and deter flies from feeding.
  • Using over-the-counter sprays. Never use a product on your pet that isn’t intended for them. Check with your veterinarian for pet-safe insect repellent product recommendations. According to the ASPCA, both dogs and cats are sensitive to DEET. Using it could cause neurological problems, such as tremors, seizures, or even death. Never use medication formulated for dogs on cats.

You may also opt to limit your dog’s outdoor playtime if you want to avoid black fly bites. Indoors, you can offer much-needed stimulation through puzzle toys and other interactive games. You may also feed them using a snuffle mat or slow feeder for extra entertainment.

Consult a Veterinarian if You Notice These Signs

“The lesions of bites from the black fly will typically resolve on their own in a week or so, and no treatment or extra worrying is necessary,” Dr. Klein says.

However, he also shares that there are some unique circumstances that may call for a veterinarian’s insight. For instance, some dogs are hypersensitive to black fly bites, especially if they’ve been bitten by the insect before. You should consult your dog’s veterinarian if you notice hives or facial swelling.

In the same vein, some dogs are also allergic to black fly bites. Dr. Klein advises, “In rare cases of rare, severe allergic reaction or anaphylaxis, (vomiting, diarrhea, excessive salivation, collapse), one must seek immediate emergency treatment for your dog.”

This article is intended solely as general guidance, and does not constitute health or other professional advice. Individual situations and applicable laws vary by jurisdiction, and you are encouraged to obtain appropriate advice from qualified professionals in the applicable jurisdictions. We make no representations or warranties concerning any course of action taken by any person following or otherwise using the information offered or provided in this article, including any such information associated with and provided in connection with third-party products, and we will not be liable for any direct, indirect, consequential, special, exemplary or other damages that may result, including but not limited to economic loss, injury, illness or death.

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