Infectious disease · Updated 2026-09-29
Lyme disease in dogs
A tick-borne bacterial infection; most exposed dogs never become ill, but some develop lameness, fever or, rarely, kidney disease.
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Signs to watch for
- Shifting-leg lameness
- Swollen, painful joints
- Fever
- Lethargy and poor appetite
- Rarely: increased thirst from kidney involvement
Causes and risk factors
Borrelia bacteria passed by infected ticks, usually after the tick has fed for 24–48 hours.
How veterinarians diagnose it
Blood tests combined with signs and exposure history; a positive test alone does not mean disease.
Treatment and management
A course of antibiotics, usually with quick improvement in joint signs, plus pain relief where needed.
Prevention
Year-round vet-recommended tick prevention, daily tick checks after walks and correct tick removal with a tick hook.
Outlook
Good for joint disease; the rare kidney form is serious.
Common questions
- What are the signs of lyme disease in dogs?
- Shifting-leg lameness; Swollen, painful joints; Fever; Lethargy and poor appetite; Rarely: increased thirst from kidney involvement.
- What causes lyme disease in dogs?
- Borrelia bacteria passed by infected ticks, usually after the tick has fed for 24–48 hours.
- How is lyme disease in dogs diagnosed?
- Blood tests combined with signs and exposure history; a positive test alone does not mean disease.
- How is lyme disease in dogs treated?
- A course of antibiotics, usually with quick improvement in joint signs, plus pain relief where needed.
- Can lyme disease in dogs be prevented?
- Year-round vet-recommended tick prevention, daily tick checks after walks and correct tick removal with a tick hook.
- When should I contact a veterinarian?
- See a vet if your dog becomes lame, stiff, feverish or unusually tired after possible tick exposure, and ask about tick prevention where Lyme disease is common. Dogs do not pass Lyme disease directly to people, but you share their tick exposure, so check yourself too.
Preparing for a lyme disease in dogs consultation
- Record when these signs began and how they changed: Shifting-leg lameness; Swollen, painful joints; Fever. Record appetite, water intake, toileting and any medicines or supplements.
- The listed urgency is prompt; worsening breathing, collapse, seizures or severe pain can make any situation an emergency. Ask the clinic rather than relying only on this category.
- Ask what else could explain the signs, which tests would change the plan and how discomfort will be managed. Symptoms alone cannot confirm this condition.
- Before going home, agree what to monitor, when to recheck and which signs mean calling sooner. Follow the individual treatment plan; do not copy another pet's prescription.
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Sources on this topic
Pages on this specific subject from recognised organisations. They are cited for further reading and do not mean the organisation has reviewed this page.
- Lyme Disease (Lyme Borreliosis) in Dogs — Merck Veterinary Manual
- Lyme disease in dogs — American Veterinary Medical Association
- Lyme disease — Cornell Riney Canine Health Center
Guidance libraries and further reading
These organisations publish relevant guidance. Their links are further reading, not evidence that they have reviewed this page.