Lyme Disease: Treating Lab Results Versus Treating The Dog

by Dr. Lorie Huston, DVM

In certain parts of the United States, this is a scenario that happens relatively often. Your dog has a routine test performed for Lyme disease which comes back positive. But your dog is not ill and is showing absolutely no sign of disease.

In my part of the country, roughly 50% of the dogs that are tested come back with a positive test result for Lyme disease. Now, the question becomes: What should you do?

Should you treat your dog with antibiotics even though he is not sick?

In all honesty, this is a complicated question and not all veterinarians and other experts agree on which answer is right. One of the things that complicate matters is the fact that approximately 95% of these dogs that test positive will never get sick with Lyme disease. However, we have no way to identify which dogs make up that 5% that may become symptomatic.

The Argument For Treating All Lyme Disease Positive Dogs with Antibiotics

Some veterinarians recommend treating all dogs that test positive for Lyme disease with antibiotics, usually doxycycline. These veterinarians argue that doxycycline is a safe antibiotic associated with minimal risk of side effects. In their minds, the risk of the dog developing Lyme disease is higher than the risk of treating with the antibiotic.

The Argument Against Treating All Lyme Disease Positive Dogs with Antibiotics

There are other veterinarians that advise against treating an apparently healthy Lyme positive dog with antibiotics. There are many different reasons for this recommendation:
  • Approximately 95% of these dogs will never get sick from Lyme disease anyway.
  • We have no definitive proof that administering antibiotics actually decrease the dog’s chance of developing a disease. In many cases, the antibiotics do not completely clear the Lyme disease organism from a dog’s body.
  • Though the risks associated with administering doxycycline are minimal, they are not non-existent.
  • There is also the risk of antibiotic resistance developing due to the misuse of antibiotics. This poses a risk to the entire population.

What Should You Do for Your Lyme Positive Dog?

I’ll offer my opinion. Your veterinarian may agree or disagree. I won’t criticize your veterinarian if she feels differently than I do but this is what makes sense to me.

I don’t typically recommend treating otherwise healthy dogs that test positive for Lyme disease. I can’t justify in my own mind using an antibiotic to treat what amounts to little more than a blue dot on a test strip. However, I do recommend monitoring your Lyme positive dog closely for signs of Lyme disease.

Part of the monitoring should be periodic blood screens to monitor kidney function. I also advise testing of urine, particularly looking for evidence of protein in the urine. Also known as proteinuria, protein in the urine may be the first sign of kidney disease in Lyme positive dogs.

If your dog begins to show signs of kidney disease, as evidenced by changes in blood or urine tests, or if other symptoms of Lyme disease (lameness, fever, etc.) occur, then I would advise treatment with doxycycline.

Though we don’t completely understand why kidney disease occurs in some dogs with Lyme disease, this is generally a serious presentation of Lyme disease for a dog and is more difficult to treat than lameness and some of the other symptoms that may occur as a result of Lyme disease.

Articles by Dr. Huston:
Lyme Is Lame (Pun Intended)
The Ticking Bomb
Don't Let Heartworm Become A Heartbreak!
Summer Perils: Blue-green Algae
Your Dog And Leptospirosis
Canine Parvovirus
Canine Distemper Virus
Why Is My Dog So Itchy? Top 5 Causes Of Itching In Dogs 
Vaccination Concerns and Potential Side Effects 
Natural Flea Control for Dogs 
Vomiting in Dogs: Is He Actually Vomiting?
Causes of Vomiting in Dogs
Is Your Dog Showing Signs Of Kidney Disease? How Is It Diagnosed?
Chronic Versus Acute Pain In Dogs: What Is The Difference? 


  1. I do not generally suggest healing otherwise healthy pets that analyse positive for Lyme condition. I cannot rationalise in my own mind using an anti-biotic to cure what amounts to little more than a red dot on a analyse remove.

    1. Yes, particularly since the red dot signifies exposure but doesn't tell you whether it was from past vaccination, resolved infection or what. This type of test doesn't differentiate between that and an active infection.

      I read about a test that is supposed to tell the difference; the Multiplex Lyme Disease Test.


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