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Black Fly vs Tick Bite on Dog: Are They Dangerous?

Black fly bites, compared to tick bites, do not pose a threat to your pet’s life. Fly bites are itchy and can get infected, but no more than that. Ticks can carry dangerous diseases they transmit through their bite, endangering your dog’s life. Both types of bites are commonly seen in dogs as warm seasons come.

Responsible pet parents are alarmed when they see red spots on their dogs. 

At first glance, black fly bites can be mistaken for ringworms. As time passes, these spots begin to look like bulls-eye marks and you can rest assured that it is not Lyme disease.

Opposite to flies, tick bites do not develop the typical bulls-eye pattern. This characteristic rash appears in relation to Lyme disease in humans, but not on dogs. 

In this article, you will learn about black fly versus tick bite on dogs, what a tick bite looks like, what a black fly bite looks like, and whether they are dangerous to pets.

What Does a Black Fly Bite Look Like on a Dog?

Black fly bites look like flat, red spots, about the size of a nickel. They are often mistaken for ringworms. In some cases, these bites can develop a bull’s-eye pattern that is often confused with Lyme disease transmitted by ticks.

These small, black insects emerge in the warm season. They live near rivers and streams and are most active on cloudy days with high humidity and low winds.

Like ticks, black flies feed on blood. The most common areas where you can see bites of black flies on your dog are the abdomen or other areas with less hair.

The bite appears as a red mark. These can get as big as a nickel. Markings can have a central clear ring that slowly expands, known as a bull’s-eye mark. This mark is often confused with the one that appears in people after being bitten by a tick infected with Lyme disease. 

Dogs do not get this distinctive mark if they are bitten by an infected tick.[1]

Black Fly Bite on a Dog
Image Source

What Does a Tick Bite Look Like on a Dog?

Tick bites often look like a small, red bump, but they can have many different appearances. If there are no complications, a tick bite disappears on its own in a few days.

Ticks are small arachnids that feed on blood. They become more visible on your dog’s skin as they grow in size due to feeding. They usually attach to areas with thin skin, such as:

  • Under the armpit (subaxillary)
  • At the base of the ears
  • In the neck area
  • Between the skin folds
  • Between the toes

Other signs of ticks on your dog are skin irritations and redness.

Tick bites appear on dogs as small, red bumps, similar to mosquito bites. These bumps become visible after a tick detaches itself or gets removed.

Related: Engorged Tick on Dog

Engorged Ticks Fall Off the dog

Are Black Flies Dangerous to Dogs?

Black flies do not pose a risk to pets as they do not carry diseases. Their bites are often resolved in a few days without any complications, as long as you treat them correctly.

Black fly bites are not dangerous to dogs; they do not transmit diseases.

A black fly bite can get infected if the dog is dirty around the bite area, or if the bite is scratched too much. This can happen to any other insect bites. 

If the bite area does not improve or get worse within 48 hours, you should contact your vet. The vet can determine whether or not antibiotics are needed to treat infected black fly bites.

In rare cases, dogs can suffer from an allergic reaction to the bite.

There are several symptoms of allergic reactions in dogs:

  • Anaphylactic shock/swelling
  • Wheezing or shortness of breath
  • Swelling of the face, gums, eyes, mouth
  • Rash
  • Incoordination
  • Hypersalivation
  • Digestive problems, especially diarrhea

If you see any of these symptoms in your dog after it got bitten by a black fly, contact the vet immediately.

Black Fly Bite Symptoms

The most common symptoms seen in black fly bites on dogs are

  • Nickel size flat, red marks
  • Itchiness
  • Redness

Itchiness represents the biggest downside of black fly bites[2]. The itchiness can be so intense that it can become painful. This reaction occurs as an allergic response of the body to the saliva they inject while feeding.

Keep your pet’s lesions clean using pet-safe products and antibacterial cream. Prevent your dog from grooming or scratching the skin marks as they can get infected.

Black Fly Bite Symptoms
Image Source

Are Ticks Dangerous to Dogs?

Ticks can be dangerous to dogs. Through their saliva, ticks can transmit various diseases that can be life-threatening to pets and humans. Not all the ticks you find on your dog are infected with pathogens.

Ticks are mostly known and feared for transmitting Lyme disease in humans and dogs. They do transmit other diseases to dogs:

  • Rocky Mountain spotted fever
  • Anaplasmosis
  • Babesiosis
  • Ehrlichiosis
  • Hepatozoonozis
  • Bartonellosis

If a tick has not had the chance to become engorged (fully fed), there is little to no chance of transmitting diseases to your pet. An infected tick transmits pathogens 36-72 hours after attaching itself to its host.

Ticks can transmit more than one disease at a time.

If you find ticks on your dog, make sure you remove them safely and completely and keep an eye out for any symptoms your dog may develop.

Tick Mark on Dog skin

Tick Bite Symptoms

Tick bite symptoms are usually represented by:

  • Local reactions (redness)
  • Small bumps, similar to mosquito bites
  • Itchiness
  • Granulomas or allergic reactions

Granulomas usually occur after removing a tick and leaving its mouthparts still attached to your dog’s skin. It can also develop due to long-term exposure to a tick’s saliva.

If your dog was bitten by a tick and a granuloma occurred at the bite site, talk to your vet as it can be surgically removed.[3]

As in the case of black fly bites, a tick bite can get infected. Most tick bites are harmless and do not require medical treatment.

Related: How to Remove a Tick From a Dog


Black flies and ticks are common pests seen in the warmer months. They attack or crawl on dogs to feed with their blood. They leave behind bright red marks after biting that can be easily distinguished.

While the black fly poses no danger, some ticks can transmit various pathogens and endanger your dog’s life. The worst thing that can happen if your dog has been bitten by a black fly is an allergic reaction, which usually occurs within minutes.

If you find a tick on your dog, remove it properly, dispose of the tick, and disinfect the area. If you see any symptoms, contact the veterinarian.

Some bites (tick or black fly) can become infected. What you need to do is to keep the lesions clean and use antibacterial cream. A granuloma might occur at the bite site if the tick was attached for too long. Granulomas can be successfully removed surgically.

About Iulia Mihai (DVM)

Dr. Iulia is a certified veterinarian with more than 10 years of experience in the field. With extensive knowledge of diet, care, and medication, she helps Misfit Animals provide readers with accurate knowledge on technical topics.

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