What is Lyme disease?
Lyme disease is an infection that dogs can get from the bite of a black-legged tick, also called a deer tick. These ticks can carry bacteria called Borrelia burgdorferi.
After a dog gets infected, the bacteria can affect several parts of the body. In dogs, Lyme disease most often causes joint pain or swelling.
Where is Lyme disease common?
Ticks that carry Lyme disease live in many parts of North America. Risk is higher in some areas. Higher-risk areas include:
- The Northeast
- The upper Midwest
- The Mid-Atlantic
- Parts of the West Coast
Ticks that carry Lyme disease tend to thrive in places like:
- Wooded areas
- Brush or tall grass
- Leaf litter
- Yard edges near forests or trails
Black-legged ticks can be very small. Some are as small as a poppy seed. Because they're so small, many pet parents never see the tick.
Tick activity changes by region and season. In many areas, ticks stay active beyond summer. Over time, Lyme disease has spread to more areas.
How do dogs get Lyme disease?
Dogs get Lyme disease through the bite of an infected tick. Most dogs only become infected if the tick stays attached for 24–48 hours. This is why quick removal is important.
Dogs can’t spread Lyme disease directly to people or other pets. But if your dog picks up infected ticks, people and other pets in your home may be at risk. Reducing contact with infected ticks helps protect the whole family.
Dogs that spend time outdoors may encounter ticks. This can happen even in cities. Your vet can help you understand local risk. They can also recommend the best prevention plan.
What are the symptoms of Lyme disease in dogs?
When Lyme disease causes illness, it most often affects the joints. Signs can show up weeks or months after a tick bite.
Common symptoms may include:
- Limping that may shift from one leg to another
- Stiffness
- Swollen or painful joints
- Fever
- Low energy or tiredness
- Swollen lymph nodes
These signs may come and go. Pet parents may mistake them for injury or aging. A small number of dogs develop a serious kidney condition called Lyme nephritis. This condition can be life-threatening.
Dogs of any age, breed, or size can get Lyme disease from an infected tick. Risk is higher for dogs who:
- Live in or travel to regions where Lyme disease is common.
- Spend time in wooded, grassy, or brushy places.
- Have an active lifestyle.
- Spend time outside, even in backyards or city parks.
In high-risk areas, many dogs encounter infected ticks. Only a small number become sick. Many dogs never show symptoms. Routine screening helps vets detect contact with infected ticks early. It also helps them decide if follow-up care is needed.
Dogs that test positive have a higher long-term risk of chronic kidney disease (CKD). This risk exists even if they never get sick. For this reason, vets may recommend monitoring and follow-up testing.
How do vets test for Lyme disease?
Vets often test for diseases spread by ticks during routine check-ups. This is common in areas where ticks live. Vets call these “screening tests.” They check for infection when your pet looks healthy.
Your vet may:
- Run a blood test.
- Perform a physical exam.
- Ask about your dog’s lifestyle and travel.
Some dogs test positive but look healthy. In these cases, vets may suggest more testing. They may also check kidney health to look for Lyme nephritis.
Dogs that test positive have a higher lifetime risk of CKD. Because of this, vets may suggest ongoing kidney health checks as part of your dog’s long-term wellness care.
Your vet will guide you on the next steps.
Why does my vet want to test for Lyme disease every year?
Dogs can be exposed to infected ticks more than once. Regular testing helps your vet detect new infections and monitor long-term health risks.
Routine screening and monitoring help vets:
- Find infection early.
- Identify re-infection, because even dogs successfully treated for Lyme disease in the past are at risk of getting infected again.
- Treat symptoms if they appear.
- Watch for Lyme nephritis.
- Monitor for CKD.
- Adjust tick prevention plans.
- Identify tick risk in your area.
How is Lyme disease treated?
When needed, treatment of Lyme disease typically includes:
- Antibiotics to treat the bacterial infection
- Anti-inflammatory medications, if joint pain is present
- Rest during the recovery period
Many dogs improve after starting treatment, but response and recovery time can vary. Dogs with Lyme nephritis need more care. These cases are rare.
Your vet may schedule follow-up visits to ensure treatment is working and to monitor your dog’s recovery.
How can I reduce my dog’s risk of Lyme disease?
Protecting your dog from Lyme disease requires several steps. Using more than one prevention method lowers your dog's risk. However, these methods can’t eliminate the risk completely.
Key steps include:
- Use vet-recommended tick prevention year-round.
- Check for ticks regularly and remove them quickly.
- Keep grass short and clear yard debris.
- Avoid dense brush when possible.
- Talk with your vet about the Lyme vaccine.
- Discuss routine testing.
Ticks are spreading to new areas. Regular conversations with your vet help keep your plan up to date.
When should I contact my vet for a tick bite or Lyme disease?
You know your dog best—if something feels off, it’s always okay to reach out.
Contact your vet if your dog:
- Has limping or stiffness that lasts more than 24–48 hours
- Has swollen joints
- Seems to be in pain or very tired
- Shows behavior or appetite changes
Seek urgent veterinary care if your dog has:
- Vomiting
- Loss of appetite
- Changes in urination
- Increased water intake
- Extreme tiredness
If you find a tick on your dog, remove it promptly and monitor your dog.
If you’re unsure whether your dog should be seen—or if any symptoms develop—contact your vet for guidance.
The bottom line: Partner with your veterinarian
Many dog owners worry about Lyme disease. This matters more as ticks spread to new areas.
Fortunately, most dogs who encounter infected ticks remain healthy. Those who get sick usually respond well to treatment.
Routine screening, tick prevention, and regular conversations with your vet can help reduce risk and support early detection of Lyme disease. If you have questions about Lyme disease, tick prevention, or testing, your veterinary team is the best place to start. A conversation during your dog’s next wellness visit can help keep them healthy and protected.
Frequently asked questions
Frequently asked questions about this topic
Many dogs that test positive for Lyme disease do not develop signs of illness and may not need treatment. When treatment is recommended, most dogs respond well and their symptoms resolve. If your veterinarian recommends treatment, they can help you understand what improvement may look like for your dog.
Most dogs don't develop life-threatening illness. In rare cases involving the kidneys (Lyme nephritis), Lyme disease can be severe and even life-threatening.
Yes. Many dogs test positive but never develop illness.
Symptoms typically appear weeks to months after a bite from an infected tick. Because ticks are small and easy to miss, many dogs don’t have a known tick bite before signs appear. If your dog tests positive, your vet may recommend more testing. These tests help determine whether your dog has an active infection and set a baseline for future monitoring.
No. Lyme disease is not spread directly from pets to people or from one animal to another. It is transmitted through the bite of an infected tick. If your dog is exposed to infected ticks, it may indicate a shared environmental risk for your household.
