Lyme Disease in Dogs

Lyme disease is caused by the bacterium Borrelia burgdorferi, which is transmitted through the bite of infected black-legged ticks, also called deer ticks. Transmission usually requires the tick to stay attached for about 24 to 48 hours, so fast tick removal matters. Dogs in the Northeast, mid-Atlantic, upper Midwest, and other expanding tick-endemic regions are at higher risk, especially if they spend time in tall grass, woods, brush, or leaf litter. Most exposed dogs remain clinically normal, but some develop illness weeks to months later.

Risk factors include:

• Living in or traveling to Lyme-endemic areas
• Outdoor activity in wooded, grassy, or brushy environments
• Inconsistent tick prevention
• Heavy tick exposure during warmer months or during mild winter periods
• Possible breed predisposition for Lyme-associated nephropathy, especially Labrador Retrievers, Golden Retrievers, and Shetland Sheepdogs

Diagnosis is based on a combination of history, exam findings, and testing rather than a single test alone. Your veterinarian will ask about tick exposure, travel history, vaccination status, and when symptoms started. On exam, they may find fever, enlarged lymph nodes, painful joints, or shifting lameness.

Common diagnostic steps include:

• In-clinic or laboratory antibody testing, often with a C6-based assay to document exposure
• Bloodwork to look for inflammation and assess overall health
• Urinalysis and urine protein testing, because protein loss can signal kidney involvement
• Kidney values and blood pressure assessment if Lyme nephropathy is a concern
• Joint fluid analysis, PCR, or other tests in select cases to rule out other causes of lameness

A positive antibody test does not always mean Lyme disease is causing the current illness, because many dogs in endemic regions test positive but never become sick.

Dogs with clinical Lyme disease are typically treated with a several-week course of prescription antibiotics chosen by a veterinarian. Pain control and supportive care are often added for sore joints, fever, and reduced appetite. If kidney complications are present, treatment may also include hospitalization, fluid therapy, monitoring of urine protein, blood pressure management, diet changes, and additional medications directed by your vet.

Management may include:

• Prescription antibiotics for dogs with compatible signs and positive testing
• Pain relief and supportive care for inflammation and discomfort
• Monitoring urine protein and kidney values after diagnosis
• Strict year-round tick prevention to reduce reinfection risk
• Tick checks after walks and prompt tick removal
• Discussing Lyme vaccination with your veterinarian if your dog lives in or travels to a higher-risk area

Many dogs with joint-related Lyme disease improve quickly after treatment, but recurrence or reinfection can happen, especially in tick-endemic areas.