What are fleas?

Fleas are tiny black-brown insects, 2-4 mm in length (about the size of a sesame seed). We mistakenly think that fleas live on our pets but actually they live in the environment. This includes our home or backyard. Fleas only visit our pets to feed. They can jump 200 times their own body length - up to 13 inches!

When fleas jump on our dogs, they apply saliva to the skin which prevents the blood from clotting while they feed. Some dogs develop allergic reactions known as flea allergy dermatitis (FAD) from the proteins in the flea saliva.

How did my dog get fleas?

Fleas jump onto our dogs when they’re out in the backyard, or on a walk or hike. Fleas can also find other ways to reach our dogs, such as traveling on our clothing, in our cars, or on other pets in the household.

How can I tell if my dog has fleas?

You don’t always see fleas on your dog because they live in the environment, not actually on your dog. Fleas hop on dogs only to feed, then hop off again. Often, you’ll see black dirt that looks like pepper in your dog’s hair coat. This material, called “flea dirt”, is actually flea feces composed of digested blood.

A simple way to determine if the black dirt is flea poop is to wipe your dog’s fur with a damp paper towel, add a drop of water, and the flea dirt will turn red. This is the easiest way to determine if your dog has fleas as it can be challenging to find fleas in their fur unless your dog is heavily infested.

Additionally, there are commercially available fine tooth combs that you can use to help separate the live fleas and flea dirt from your dog’s haircoat to get a more accurate assessment.

Signs Your Dog May Have Fleas:

• Scratching more than normal

• Areas of hair loss

• Red and irritated skin

• Thickened or crusty skin, especially around the ears or at the base of the tail

• Black flea dirt in the fur or visible fleas

• Insect bites on you or others in your home, especially on the ankles

Can fleas make my dog sick?

Fleas in large numbers, particularly on small dogs, can cause life-threatening blood loss also known as anemia. Fleas are blood-sucking insects and in large numbers can quickly deplete small or young dogs of their blood supply. Check your dog often for signs of fleas and if you notice your dog is sleeping more than normal, is less active, or appears weak, contact your veterinarian right away.

Dogs sometimes groom themselves by licking and can ingest hair and adult fleas in the process. Adult fleas carry and transmit tapeworms when ingested. Often a dog will experience no signs or symptoms. However, tapeworm infections can cause upset stomach, vomiting, weight loss, decreased appetite, and diarrhea. In rare cases, tapeworms can be indirectly transmitted to humans.

One of the most common diseases that your dog can get from a flea infestation is flea allergy dermatitis, or FAD. This is an allergic reaction to the proteins in the flea saliva when the fleas bite your dog for a blood meal. It results in a dog who is very itchy, often disproportionately to the actual number of fleas on your dog. Dog’s with FAD will have hair loss and skin irritation and can even stain their haircoat reddish-brown from the constant licking and chewing.

While uncommon, there is a risk of transmission to humans of a highly contagious bacteria called Yersinia pestis, commonly known as the Bubonic plague. This disease can be carried by rodent fleas. Dogs can carry infected fleas, which pose a direct and life-threatening risk to humans.

What is the best way to treat a flea infestation?

The best way to manage fleas is to understand the flea life cycle. If you treat just your dog for fleas, you’re only treating a small percentage of the flea life cycle. About 5% of adult fleas actually live on your dog. The other 95% of the flea’s life cycle is spent in the environment (home, back yard, etc.) as eggs, larvae, pupae, and adult fleas. Learn more about the flea life cycle by clicking here!

To manage and control flea infestations, treatment must include ALL pets in your household, and your home environment, both inside and outside. Fleas lay their eggs in cracks, crevices, and soft furnishings, and those eggs can survive up to a year. This makes treating your dog’s environment a key part of flea control.

The eggs are usually the most difficult part of the cycle to kill. Household/outdoor flea treatment sprays must NEVER be used on animals as they contain toxic ingredients that can cause severe and sometimes fatal side effects. Read all instructions for household/outdoor flea treatment sprays before using. Consider calling an exterminator with experience treating homes and outdoor environments for fleas, especially if you have a severe flea infestation.

Vacuum all floors, especially floorboards and under beds/furniture, and upholstered furniture every day for 14 days after your home has been treated. The vibrations from vacuuming attract larvae from within the carpet, and unhatched eggs hatch out and die from the chemical treatment. Remember to throw away or empty the vacuum cleaner bag outside or place the contents of the vacuum cleaner in a plastic bag, tie it up and dispose of it away from your home. Wash your dog’s bedding in hot water (140°F/60°C) to kill flea eggs and larvae.

There are many options when it comes to treating your dog for fleas, and not all flea treatments are the same or safe for your dog. The best resource for picking a safe and effective flea treatment and management plan is a licensed vet.

Flea treatments work by killing fleas on contact with the chemical in the dog’s fur or when the flea ingests the chemical from your dog’s bloodstream during a blood meal. Over-the-counter flea treatments sold in pet stores, on-line, and in the grocery store often contain ingredients that may not be safe and can be much less effective than those prescribed by your vet.

It often takes 3-6 months of intensive flea treatment to control and manage a flea infestation.

Still seeing fleas after treating your dog and your home?

Managing flea infestations can be frustrating. Reasons why you may still be seeing fleas after treating both your dog and your home include:

• Not treating all the animals in the household

• Not treating your car or other areas where your dog spends time, like a kennel for example

• Washing your dog or letting them swim too soon after using a spot-on/topical flea product

• Using the wrong flea product on your dog or your house, or not treating long enough

Read more:

Deworming Your Dog - Q&A

How to Apply “Spot On” Medication to Your Dog or Cat

Have more questions about managing fleas in dogs?

Schedule a video consult to speak to one of our vets.