Fleas and Ticks on Dogs: Why Prevention Is Important

Aside from the annoying itchiness they cause, fleas and ticks can carry diseases that are dangerous for dogs. From tapeworms to Lyme Disease, these illnesses are sometimes fatal if left untreated. Prevention is the number one defense against the harmful effects fleas and ticks can have on your dog.

Here are a few of the diseases fleas and ticks carry, along with some tips on how to prevent the parasites from getting to your dog.

Flea Allergy Dermatitis

Flea allergy dermatitis is the most common problem associated with flea bites. While it can lead to extreme itchiness, hair loss, and skin lesions, it’s never fatal. An allergic reaction, rather than a disease, flea allergy dermatitis is the most common skin disease in dogs in the United States.

Symptoms of flea allergy dermatitis include:

  • Excessive scratching, biting, or licking
  • Small red bumps that look like pimples
  • Hair loss in area(s) where bite(s) may have occurred
  • Skin rash or raw, irritated (and sometimes bleeding) skin

Flea allergy dermatitis is uncomfortable for your dog and can lead to skin infections. With proper treatment and continual preventative measures, most dogs recover easily.


When a dog swallows a flea while chewing at an irritating bite, it can wind up with tapeworm. Tapeworms are parasites that attach themselves to the intestinal wall. In adult dogs, they do little damage. But, in puppies, they can be more dangerous causing anemia and stunting their growth.

Symptoms of tapeworms include:

  • Scooting, wherein your dog drags its bottom across the ground to ease irritation
  • Moving tapeworm egg sacs, which look like grains of white rice or cucumber seeds, around your dog’s backside
  • Vomit with adult tapeworms in it
  • Diarrhea (often with full tapeworms or worm segments in it)
  • Weight loss

Dogs with tapeworms need deworming medication.


While anemia can be a serious threat to a dog, the number of fleas required to cause it is significant. In most cases, your dog would need to be infested with fleas to be at risk for anemia. Puppies, however, are at greater risk. Even a few fleas can drain a small puppy of too much blood.

Symptoms of anemia include:

  • Lethargy
  • White gums
  • Weakness
  • Rapid breathing

Anemia left untreated can lead to death, especially in younger dogs. If you notice any of these symptoms, call your vet as your puppy may need immediate intervention.

Lyme Disease

Lyme Disease is the most common tick-borne illness to affect dogs. In 2021, one in 20 dogs tested positive for the disease, which can cause neurological issues, joint and kidney problems, and, in extreme cases, death.

Symptoms of Lyme Disease include:

  • Loss of appetite
  • Fever
  • Fatigue or sluggishness
  • Swollen joints, stiffness, and/or lameness
  • Swollen lymph nodes

Dogs diagnosed with Lyme Disease need antibiotics. Depending on how advanced the disease is, dogs may also need other therapeutic treatments.


Not quite as common as Lyme Disease, Anaplasmosis still presents a significant risk. According to the Companion Animal Parasite Council, one in 50 dogs tested positive for the disease in 2021.

Anaplasmosis can cause several symptoms but many dogs will only remain sick for a short while. Others may never show symptoms at all. Left untreated, however, the disease can lead to respiratory issues, organ failure, and death.

Symptoms of Anaplasmosis include:

  • Fever
  • Loss of appetite
  • Signs of joint pain
  • Lethargy
  • Vomiting
  • Coughing or labored breathing

Antibiotics are the only treatment for Anaplasmosis. Most dogs show improvements in a few days.


About as common as Anaplasmosis, chronic Ehrlichiosis can cause anemia, eye and neurological problems, and joint issues. In worst cases, Ehrlichiosis can cause a dog’s bone marrow to fail, which is generally fatal. Owners of German Shepherds and Dobermans need to be particularly vigilant. In those breeds, the disease tends to be more severe.

Symptoms of Ehrlichiosis include:

  • Fever
  • Swollen lymph nodes
  • Difficulty breathing
  • Weight loss
  • Sudden bleeding
  • Anemia
  • Lameness
  • Blindness

Some dogs recover from Ehrlichiosis on their own. Others will need an antibiotic.

Rocky Mountain Spotted Fever (Tick Fever)

Like the other tick-borne diseases, Rocky Mountain Spotted Fever can be fatal if left untreated. About 10% of dogs with the disease die, while 30% experience severe central nervous system symptoms. Late treatment can lead to permanent organ damage.

Symptoms of Rocky Mountain Spotted Fever include:

  • Fever
  • Loss of appetite
  • Joint inflammation
  • Vomiting and/or diarrhea
  • Swollen lymph nodes
  • Coughing and/or breathing difficulties
  • Signs of abdominal pain
  • Swelling of the face or limbs
  • Impaired balance (in severe cases)
  • Purplish-red spots inside of the eyelids and mouth (in severe cases)
  • Altered mental state (in severe cases)
  • Extreme spinal sensitivity (in severe cases)

If you live in an area where Rocky Mountain Spotted Fever is common (mostly the Southeast USA) and know your dog was bitten, call your vet immediately. Any delay in antibiotic treatment can lead to symptoms and serious illness. Dogs diagnosed and treated early generally recover quickly.

Protecting Your Dog from Fleas and Ticks

A good offense is the best defense when it comes to fleas and ticks and dogs. Yes, use a flea comb during grooming. Yes, check for ticks after a walk outdoors. But preventative measures are the only surefire way to stop these parasites from biting, and potentially infecting your dog with a life-threatening illness.

The best protection you can give your dog comes from flea and tick preventatives. Available in several forms, preventatives work by killing off living fleas and ticks, while also stopping them from reproducing. Each preventative works differently. Your vet can recommend the right choice for your dog.

Don’t only give preventatives in the spring and summer. Fleas, in particular, are a year-round problem. Taking a break when the temperatures go down gives them a chance to reinfest your pet.

Generally speaking, flea collars can be used in conjunction with preventatives. (Except Seresto flea collars; talk to your vet before combining with any other treatment.) They are particularly helpful if you and your dog are going someplace fleas and ticks are abundant (like a walk through the woods). Choose a collar that repels as well as kills, as this prevents them from biting your dog in the first place.

You can also use a product like SecureAway Flea Collar Protectors to keep the flea collar in place.