How to Tell if a Dog Has Fleas

Dr. Joe Alcorn, M.S., D.V.M.

Dr. Joe Alcorn is founder of Care Animal Hospital in Temecula, California. He has a Bachelor of Science in Biology and Doctor of Veterinary Medicine from Colorado State University. He is a member of the American Veterinary Medical Association and his advice has been featured in large publications like Bustle and Martha Stewart.

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Fleas are external parasites that depend on a host to survive. Adult fleas can quickly reproduce and if left untreated can lead to other serious diseases or infections for your dog. Being aware of the symptoms of a flea infestation can be quite helpful when it comes to how to tell if a dog has fleas. 

How to Tell if a Dog Has Fleas

Dogs with flea infestations are at the risk of developing other health issues such as anemia or tapeworm. In extreme cases, this can lead to death. However, this can be prevented with an early diagnosis and treatment. There are a few symptoms and signs to look out for to detect this. 

Dog scratching from itchy skin


If you notice an unusual level of biting or scratching by your dog, this might be caused by a flea infestation. Fleas tend to cause an irritating sharp pain when they bite, this can lead to your dog repeatedly gnawing at that spot. 

Most dogs also tend to be hypersensitive to the substance produced from the salivary glands of a flea. This can cause them to continuously itch all over for long hours or several days. In some cases, the dogs become anxious or agitated.

Hair Loss

Hair loss can sometimes occur in a dog infested with fleas. This can either be a result of excessive scratching or dry skin.  Common spots where fleas hide are around the tail, groin, armpits, and neck. If you notice hair loss in your dog around these spots, you should consult me for professional help.

Visual Inspection

A visual inspection can be done in different ways during a grooming section with your dog.

Using a Magnifying Glass

Fleas can be quite tiny to the naked eye, even when they are fully grown. They are mostly reddish-brown and they look tiny. Part your dog’s hair into sections and check for unusual spots or colors with a magnifying glass. 

Watching Out for Flea Dirt

You can place a white sheet beneath your dog and ask them to shake it off. If you notice tiny black specks on the sheet, try to sprinkle some water on them. These black specks will turn red if they come in contact with water confirming that your dog is indeed infested.

Using a Flea Comb

This simple process can be done while grooming your dog. Starting quite close to your dog’s skin, brush through in sections with a flea comb. You should catch some on the comb if they are present. You can dump them in a bowl of water to prevent re-infestation. 

Veterinarian checking dogs from fleas

Performing a Physical Inspection

You should periodically inspect your dog’s fur, legs, and underbelly for unusual bumps or spots. A common telltale sign is its red color. Fleas like to stay hidden in warm areas, so make sure your check is thorough. Overly irritated skin is also sometimes caused by fleas.

Flea Eggs 

Fleas can reproduce quickly when they are settled. Their eggs are tiny white things in an oval shape. If you notice these around the house or your dog’s resting places, it could be an indication of fleas.


Tapeworms can develop in your dog if they ingest fleas. A common indicator of tapeworms would be finding tiny white particles in your dog’s bed or chair. In this case, you should seek professional help to treat the tapeworm and flea. 

Blood Loss

Fleas are blood-sucking pests that can drain your dog’s blood if they are large in number. If you notice your dog looking weak and pale, or presenting with pale gums, it could be a result of anemia caused by fleas.  

How to Treat Dogs With Fleas

The first and most important step would be seeking professional advice from a veterinarian. I will conduct a proper work-up and tests to determine what level of infestation your dog is dealing with and advise on the best treatment course. However, you can also provide immediate relief for your dog with these: 

  • A lukewarm bath can provide some relief and get rid of some of the fleas
  • Applying topical sprays, powders, or shampoo specially formulated for dog fleas can expel the fleas and bring relief to the dog.
  • You can also apply some chemical insecticide to get rid of the fleas that attach to the furniture or carpet.

Conducting proper tests is important for me to accurately diagnose and advise on the best course for treatment. 

How to Prevent Fleas in Dogs

It is better to prevent flea infestation in your dog or home than to deal with one. This is because fleas are as dangerous to humans as they are to dogs. A few ways to do this include:


Regular Vet Visits

I can quickly determine if your dog has an infestation at an early stage and prevent it from spreading or causing further damage. Our clinic can also check for other illnesses or issues related to fleas. Make sure you take your dog regularly to a veterinarian.

Flea Prevention Products

There are several products such as a flea prevention dog collar designed to greatly reduce or prevent flea infestation in your dog. I can recommend and prescribe you some of these products. There are some products best for daily use, while others can last for months.

Regular and Thorough Grooming 

Grooming your dog should be done regularly and thoroughly. Check them for flea bites. Keep your dog clean at all times and away from your trash bin or dirty surfaces. Avoid them rolling in dirty gardens or eating anything outside during a road walk.

Another aspect of dog grooming includes caring for your dog’s belongings and personal effects. Wash their beds, blankets, toys, and other objects thoroughly under a hot cycle. You can add some bleach, detergent, or flea prevention powder. 

You can also spray their beds and immediate surroundings with the prevention powder.

Keep Your House Clean

Save your dog from catching fleas from anywhere inside or outside the home. Keep your home and surroundings clean at all times. Vacuum your home regularly at high suction. They can suction up fleas and eggs from unusual or hidden places. Other devices such as a steam cleaner can also eliminate fleas with the soap and steam they produce


Fleas are nasty animals that can cause serious health complications to both the dog and its owner. Keep your house and dog surroundings clean to prevent infestation. Maintain regular checkups with our clinic and always seek our opinion before treating your dog for fleas.