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Lyme Disease in Dogs: Diagnosis to Treatment

Ticks are most active when warm weather hits, but in many parts of the country they can be a year-round nuisance. These tiny parasites are known for carrying diseases, including ehrlichiosis, anaplasmosis and other afflictions that can cause fevers and other symptoms, some of which can be life-threatening. One of the most well-known and common of these is Lyme disease.  

Lyme disease is a risk for any dog who lives in areas where there are ticks in the environment, but exposure can be particularly concerning for pups that spend time doing outdoor activities like hiking, camping or playing with toys in the yard. Keep in mind, however, that even dogs who spend most of their time indoors can contract this disease. Every pet parent should know the signs of Lyme disease in dogs and how to prevent and treat it. 

What is Lyme disease in dogs? 

Lyme disease in dogs—and humans—is a bacterial infection transmitted through the bite of the black-legged tick, also known as the deer tick. These ticks are common throughout the midwestern and eastern United States and Canada, especially in the province of Ontario. They commonly wait at the tips of plants, grasses and shrubs for passing animals, then climb or drop onto them. That’s why ticks prefer to live in woodlands and grasslands, including your yard.  

By some estimates, up to 50% of deer ticks may carry Lyme disease in heavily affected areas. The US Northeast, Eastern Seaboard and northern Midwest are the highest-risk areas, but pet parents everywhere should be on the lookout for early symptoms of Lyme disease in dogs so that they can treat it as soon as possible.  

What are the signs of Lyme disease in dogs? 

Lyme disease in dogs is relatively common, but the symptoms are often confused with other illnesses or are so subtle they are not recognized at all. It’s much more difficult to know when exposure has occurred in dogs than with humans because dogs don’t develop a rash as humans do.  Symptoms of canine Lyme disease can include the following. 

  • Loss of appetite 
  • Fever 
  • Generalized pain 
  • Limping or lameness

Many pet parents seek out veterinary services due to these generalized symptoms with no idea that the cause could be Lyme disease. The side effects of Lyme disease in dogs can even come and go. Your dog may appear to recover, only to begin limping and losing their appetite again weeks or months later. That’s why you should never ignore symptoms like these in your pet. 

How long does it take for a dog to show symptoms of Lyme disease? 

Early symptoms of Lyme disease in dogs can appear anywhere from two to five months after being bitten by an infected tick. Their long incubation period contributes to the confusion that often surrounds diagnosis, as pet parents don’t always recall when their dog may have been exposed to areas with ticks. This is another reason to consult your veterinarian as soon as you notice any symptoms.  

Once they show symptoms, what happens to a dog with Lyme disease? And how does this disease progress? Left untreated, Lyme disease can be fatal. Advanced Lyme disease in dogs spreads throughout the body. Once it reaches the kidneys, your dog may experience vomiting, weight loss, lethargy—and, frequently, death.  

Are there long-term effects of Lyme disease in dogs? 

Even when treated, Lyme disease in dogs can have long-term effects, depending on how far it progressed before treatment. While it is typically treated with antibiotics, there is no true cure for Lyme disease in dogs. The illness can hide within the body’s cells and flare up again, especially in dogs with a compromised immune system. Your dog may begin to show some of the initial signs such as lameness or lethargy.  

If the disease has progressed to a certain point before treatment is given, chronic kidney and heart problems can develop, including kidney failure, which has no cure. Neurological problems can also occur. Getting treatment for Lyme disease in dogs as close to the time of infection as possible is one of the best ways to help prevent long-term damage.  

What are the three stages of Lyme disease in dogs? 

While there is only one type of Lyme disease in dogs, the illness usually progresses through three stages—early localized Lyme, early disseminated Lyme and late disseminated Lyme. Early localized Lyme is very difficult to detect in dogs, as it typically manifests as fatigue, fever and joint and muscle pain. An infected dog may not actively show any of those signs.  

Similar symptoms characterize the next stage but on a more aggressive level. This stage is when your dog may start limping or losing their appetite. Late disseminated Lyme disease in dogs can affect the organs, brain and spinal cord. 

Dog parents may also mistake other illnesses as Lyme disease. Tick-borne ailments with similar symptoms to Lyme include Rocky Mountain spotted fever, babesiosis, ehrlichiosis or anaplasmosis. All these illnesses can cause fever, loss of appetite and lethargy identical to Lyme disease. 

How is Lyme disease diagnosed? 

Tick disease testing needs to be part of your dog’s routine preventive care plan. Annual screening is recommended by the American College of Veterinary Internal Medicine. Diseases such as Lyme disease can be treated more effectively when caught early such as during your dog’s regular vet checkups.

Diagnosing Lyme disease in dogs typically involves a process of elimination as well as blood tests. Your veterinarian will ask about your dog’s history, including any outdoor adventures and the progression of symptoms you have noticed. Two different tests are commonly conducted to detect Lyme disease—the C6 and the Quant C6. If your vet suspects Lyme disease, they will conduct both tests. Some vets may also include Lyme disease testing in their regular screenings using in house diagnostic tests.

When the bacteria causing Lyme disease in dogs infects the bloodstream, the body usually produces specific antibodies to fight it off. The C6 test detects the presence of these antibodies. However, a negative C6 test doesn’t necessarily mean your dog doesn’t have Lyme disease. If the bacteria has been present for a very long time or a short time, there may not be antibodies in the bloodstream to detect. That’s why diagnosing Lyme disease in dogs is notoriously tricky. Your veterinarian can follow up a negative test result with the Quant C6, as well as other tests that may indirectly indicate the presence of Lyme disease. 

What happens if your dog tests positive for Lyme disease? A positive C6 test definitively indicates that your pup has this disease. However, your vet may still follow up with the Quant C6 test to determine whether the illness is active and the level of treatment that will be required.   

What’s the treatment for Lyme disease in dogs? 

Antibiotics for Lyme disease in dogs are often required when testing shows a positive result. Typically, at least a four-week course of treatment is given. Options include doxycycline, amoxicillin and cefovecin. All are powerful antibiotics and should be given according to your veterinarian’s instructions. Sometimes treatment is required for longer than four weeks.  

Unlike for humans, there is a Lyme vaccine for dogs. It’s a preventive measure and not a cure or treatment. While some pet parents have reported a reaction to the Lyme disease vaccine in their dogs, reactions are rare and it is a great option for any dog who is at risk, especially active dogs who are frequently outdoors in high-risk areas. 

Antibiotics are currently the only treatment, but they don’t always get rid of the disease completely. There is no guaranteed cure for Lyme disease in dogs, and as we discussed above, your dog may display recurring symptoms that may need to be managed with other medications or remedies.  

How else can I help my dog with Lyme disease? 

Year-round flea and tick prevention is highly recommended when it comes to preventing Lyme disease in dogs. Even if your dog has received the Lyme vaccine, giving them preventive medicine is still necessary to help prevent the transmission of other diseases commonly carried by fleas and ticks. At Petco, we have many preventive solutions available, including collars, topical options and chewable pills. Some chewables also contain ingredients to help prevent heartworm and other internal parasites so that you can take care of multiple necessary treatments at once. Whatever type you choose—and no matter where you live—it’s highly recommended that you administer a monthly flea and tick preventive medicine.  

If your pup has kidney problems resulting from Lyme disease, they may benefit from dog food formulated for renal support. Some dog vitamins and supplements may help ease symptoms like inflammation in the joints and digestive problems. Consult your veterinarian about other types of treatment for Lyme in dogs.  

The side effects of Lyme disease in dogs are usually severe and can be deadly if not immediately addressed. It’s important to take this illness seriously. Take your dog to the vet as soon as you notice symptoms, follow all treatment instructions carefully and keep an eye out for recurring signs. Lyme disease can be a lifelong illness, but your pup can still live a comfortable life if diagnosed and treated early.  

Reviewed by Dr. Whitney Miller, DVM, MBA, DACVPM

As Petco’s Chief Veterinarian, Dr. Miller is the lead veterinary subject matter expert, overseeing the company’s standards of excellence in animal care and welfare, growth in pet services and much more. Dr. Miller leads Petco’s medical team, supporting over 200 full-service hospitals and mobile vaccination clinics operating in over 1,000 Petco Pet Care Centers nationwide