Ticks aren’t the only external parasites that feed on our canine companions—black flies also draw blood from dogs, leaving behind a bullseye-like rash at the bite site. Thankfully, black flies are more of a nuisance than a serious threat, as they don’t transmit life-threatening diseases the way ticks do.
Most black fly bites heal on their own within a few days, causing only mild skin irritation and itching. However, in some cases, it’s wise to seek a veterinarian’s advice. If the lesion appears infected or is located near sensitive areas such as the dog’s eyes or mouth, consult your dog’s healthcare team.
Black Fly Bites Are Usually Not Cause for Concern
Dr. Jerry Klein, Chief Veterinarian for the Canine Kennel Club (CKC), notes that while black fly bites can be inconvenient, they’re rarely a significant threat to a dog’s health.
“Black flies (or buffalo gnats) cause bite wounds on dogs that are large, red, or bruised and are 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 appearance of a ‘bullseye,’ similar to the rash humans get from tick bites that can carry Lyme disease.”
While dogs can develop Lyme disease, their symptoms usually include joint swelling, stiffness, and lameness rather than a target-like rash, which is specific to humans. It’s advised to keep your dog vaccinated against Lyme disease and other transmissible illnesses for overall protection.
Recognizing Black Fly Bites on Dogs
Black flies are found throughout the United States, particularly near bodies of water in late spring and early summer. These bloodsucking parasites often feed on dogs during activities like swimming, fetching, or simply being outdoors. While the bites themselves are generally painless, they can cause itching, prompting your dog to lick or bite the affected area. Excessive licking can lead to open sores, infection, and other complications, which may need veterinary attention. Preventing over-licking of black fly sores can be managed with an Elizabethan collar or by using vet-approved topical creams.
Black Fly Bites vs. Tick Bites: Key Differences
While black fly bites and tick bites might appear similar at first, there are significant differences between them:
- Feeding Behavior: Black flies often feed in swarms, so you may find multiple bites on your dog, unlike a single tick bite.
- Feeding Time: Black flies can land, feed, and leave quickly, while ticks need to attach themselves to the dog to feed, which can take anywhere from a few minutes to a few hours.
- Removal: A tick will stay latched on to the dog until manually removed, typically with tweezers, whereas a black fly will leave on its own once it has fed.
Being aware of these differences can help you better assess and care for your dog’s bites.
Black Fly Bites vs. Ringworm on Dogs
Unlike the name suggests, ringworm is not a worm but a fungal infection affecting a dog's outer skin layer and hair follicles. Dogs typically contract ringworm from contact with contaminated surfaces like shared food bowls. One key difference between a black fly bite and ringworm is the texture of the wound. Black fly bites appear flat and generally only become inflamed if they’re infected, while ringworm often feels slightly raised and may be scaly.
Another difference is the presentation. Ringworm typically appears as a solitary red ring, often on the face, tail, ear tips, or feet. Black fly bites, however, tend to occur in clusters, especially on nearly hairless areas like the underbelly.
How to Treat Black Fly Bites on Dogs
Most black fly bites heal within a few days. Dr. Klein recommends keeping the area clean by washing it with mild soapy water, applying an ice compress, and administering antihistamines (as directed by your veterinarian). Antihistamine or hydrocortisone creams may also help relieve discomfort when applied sparingly. Ensure your dog doesn’t lick the ointment for at least 15 minutes after application.
If your dog persists in licking or biting the area, your veterinarian may suggest a protective collar to prevent further irritation. The duration for which the collar is required depends on the bite’s severity and location.
How to Prevent Black Fly Bites on Dogs
Black flies are particularly common in humid, subtropical areas, especially near rivers, ponds, and streams. To prevent black fly bites:
- Avoid peak fly hours: Black flies are most active a few hours after sunrise and before sunset.
- Use protective clothing: For dogs with thin coats or exposed underbellies, like Italian Greyhounds, a lightweight coat can help deter flies.
- Use dog-safe insect repellent: Check with your veterinarian for pet-safe products. Avoid products containing DEET, as they can cause serious health issues for dogs and cats.
For additional protection, consider limiting your dog’s outdoor time during high-risk hours. You can keep them entertained indoors with puzzle toys, snuffle mats, or slow feeders.
When to Consult a Veterinarian
While black fly bites generally resolve within a week without complications, some dogs may show heightened sensitivity or allergic reactions. Consult a veterinarian if your dog displays signs of hypersensitivity, such as hives or facial swelling. Dr. Klein notes that in rare cases, black fly bites may cause severe allergic reactions, including vomiting, diarrhea, excessive salivation, or collapse, in which case emergency care is necessary.