Lyme Disease in Dogs: Symptoms, Testing, Treatment and Prevention

How Do Dogs Get Lyme Disease?

Dogs get Lyme disease from the bite of an infected black-legged (deer) tick. These ticks are tiny, about the size of a poppy seed to a sesame seed, so they are easy to miss.¹ The tick usually has to stay attached for at least 24 to 48 hours before it passes on the bacteria (specialists put it at 36 to 48 hours or more), which is why regular tick checks and prompt removal lower the risk.^1,3

• Where it occurs: Lyme disease has been reported in every U.S. state but is most common in the Northeast, the upper Midwest and along the Pacific Coast.² The black-legged tick's range keeps expanding, with rising risk reported south into eastern Tennessee and northern North Carolina, into parts of the northern Plains (North Dakota, South Dakota and Iowa) and north into Canada.⁴
• When: spring and fall are the highest-risk seasons, but adult ticks can be active whenever temperatures are above about 40°F (4°C).^2,3
• Can people catch it from dogs? No. Dogs don't infect people directly, but they can carry infected ticks into the home, where the ticks may then bite people.^1,2

Other tick-borne infections, such as Anaplasma, can occur along with Lyme disease or mimic it, so vets consider them too.³ Learn more about tick diseases in dogs and see our tick pictures.

Symptoms of Lyme Disease in Dogs

Most dogs that test positive for Lyme disease show no signs at all.³ When symptoms appear, they usually start 2 to 5 months after the tick bite.¹ Common signs include:^1,2,3

• Lameness, often shifting from one leg to another
• Swollen or painful joints
• Fever
• Low energy (lethargy)
• Poor appetite
• Swollen lymph nodes

Young, active, often large-breed dogs most often show the classic joint form.³ See also our page on low energy in dogs.

Lyme nephritis: the serious kidney form

In a small number of dogs, Lyme infection triggers an immune reaction that damages the kidneys. Protein loss in the urine is seen in fewer than 2% of dogs that test positive, and retrievers appear to be over-represented.^3,1 Signs include vomiting, poor appetite, increased thirst and urination, weight loss and extreme lethargy. Lyme nephritis needs intensive treatment and has a poor prognosis.^1,2

How Vets Test for Lyme Disease

• Antibody blood test: a quick, relatively inexpensive in-clinic test detects antibodies to the Lyme bacteria. It can take 4 to 8 weeks after a tick bite for the test to turn positive.¹
• A positive test shows exposure, not illness. Many healthy dogs in tick areas test positive, and antibody tests can stay positive for months to years after treatment, so vets diagnose Lyme disease from the test result together with the dog's signs.^3,5
• Urine protein test: specialists recommend checking every Lyme-positive dog's urine for protein, an early warning sign of kidney involvement, and rechecking it periodically.³
• Coinfection testing: infections such as Anaplasma and Ehrlichia can occur alongside Lyme disease or mimic it, so your vet may test for them too.^3,5

Treatment of Lyme Disease in Dogs

Dogs with signs of Lyme disease are usually treated with the antibiotic doxycycline for 4 weeks. It also works against several other tick-borne infections.^3,1 Your vet may add pain relief for sore joints.¹

• How fast it works: most dogs with joint symptoms improve within 1 to 2 days of starting antibiotics.¹ Some dogs don't fully recover and may have ongoing joint pain.²
• Side effects: doxycycline can upset the stomach, so give it with food. Follow each pill with water or food so it doesn't lodge in the esophagus. Elevated liver enzymes are another possible side effect.⁶
• Dogs with no symptoms: it isn't known whether treating healthy dogs that test positive helps, and most specialists on the ACVIM panel don't routinely treat them unless they are losing protein in their urine. These dogs are usually monitored with periodic urine tests.^5,3,1
• Lyme nephritis needs more intensive care, which can include hospitalization, IV fluids, medications to reduce protein loss and a kidney diet.^1,3

For general tick treatment and removal, see our pages on Lyme disease treatment, tick medicine for dogs and removing ticks from dogs.

Can Dogs Recover From Lyme Disease? Life Expectancy

Yes. The outlook for dogs with the joint form of Lyme disease is generally good, and most respond quickly to antibiotics. Some dogs don't fully recover and are left with lasting joint pain.^2,1 The kidney form is the exception: Lyme nephritis carries a poor prognosis, and many affected dogs do not survive.¹

Having Lyme disease once does not make a dog immune, so dogs can be infected again.¹ Antibody tests may stay positive for a long time after treatment, so a positive test in a healthy, previously treated dog doesn't necessarily mean it needs more antibiotics.⁵

How to Prevent Lyme Disease in Dogs

• Year-round tick control: use a tick preventive your vet recommends, all year and as directed on the label. Specialists prefer products that repel ticks or kill them quickly, before they can pass on infection.^3,1 Check the label: some popular flea and heartworm products, such as Trifexis, don't control ticks, and Revolution's only tick claim in dogs is for the American dog tick, not the black-legged tick.^7,8
• Routine tick checks: check your dog for ticks after time outdoors and remove any you find promptly with fine-tipped tweezers, grasping close to the skin and pulling straight out.^2,1 See our guide to tick removal.
• Avoid tick habitat such as tall grass, brush and wooded edges where possible, and keep your lawn short.¹
• Consider the Lyme vaccine: a vaccine is available for dogs at risk. It's given as two doses 3 to 4 weeks apart, then yearly, and should be used alongside tick control.¹ Specialists disagree on which dogs need it, so ask your vet whether it suits your dog's location and lifestyle.^3,2 Specialists don't recommend vaccinating dogs that are sick or losing protein in their urine.³

Frequently Asked Questions

What are the first signs of Lyme disease in dogs?

The most common first signs are lameness (often shifting between legs), swollen or painful joints, fever, low energy and a poor appetite. They usually appear 2 to 5 months after a tick bite, and many infected dogs never show signs at all.

Can dogs get Lyme disease?

Yes. Dogs get Lyme disease from the bite of an infected black-legged (deer) tick. It is most common in the Northeast, upper Midwest and Pacific Coast, but the tick's range is expanding.

How long can a dog live with Lyme disease?

Most dogs with the joint form respond quickly to antibiotics and have a good outlook. Dogs that develop Lyme nephritis, the kidney form, have a much poorer outlook, which is why vets recommend urine protein checks for Lyme-positive dogs.

Can Lyme disease in dogs be cured?

Most dogs with joint signs improve within 1 to 2 days of starting antibiotics and are treated for 4 weeks. Antibiotics don't always clear the infection, some dogs have lasting joint pain, and dogs can be reinfected, but most treated dogs do well.

What happens if Lyme disease goes untreated in dogs?

Many exposed dogs never get sick. In dogs that do, untreated Lyme disease can lead to joint damage and, in a small number, serious kidney disease. Nervous system and heart involvement has been reported but is uncommon and poorly documented in dogs.

How is Lyme disease tested for in dogs?

Your vet can run a quick in-clinic blood test for Lyme antibodies, ideally at least 4 to 8 weeks after a tick bite. A positive result shows exposure, so your vet will also consider your dog's signs and may check the urine for protein.

Is doxycycline used to treat Lyme disease in dogs?

Yes. Doxycycline, usually given for 4 weeks, is the first-choice antibiotic. Give it with food and follow each dose with water or food to avoid stomach upset and irritation of the esophagus.

Can I get Lyme disease from my dog?

No. People don't catch Lyme disease from dogs. But dogs can bring infected ticks into the house, so check both pets and people for ticks after time outdoors.

Do dog ticks carry Lyme disease?

Most Lyme infections come from the black-legged (deer) tick, although several tick species can carry the bacteria. Since you can't always tell ticks apart, remove any tick promptly and use a preventive that covers the ticks in your area.

Should my dog get the Lyme vaccine?

It depends on your dog's risk. Vaccination may be recommended for dogs living in or traveling to areas where Lyme disease is common, alongside year-round tick control. Your vet can help you decide.