Lyme Disease in Dogs: Causes, Symptoms, and Treatment

Lyme disease in dogs is one of the most common tick-borne illnesses in the United States, and it’s far more serious than many pet owners realize. Caused by a bacterium transmitted through tick bites, Lyme disease in dogs can affect the joints, kidneys, heart, and nervous system. The good news is that with early detection and proper treatment, most dogs recover well. Knowing the causes, symptoms, and treatment options puts you in the best position to protect your dog.

 

 

What Causes Lyme Disease in Dogs?

Lyme disease in dogs is caused by the bacterium Borrelia burgdorferi, which is transmitted through the bite of an infected black-legged tick, commonly called a deer tick. These ticks are found throughout much of the eastern United States, including Pennsylvania, making Lyme disease a very real concern for dog owners in the Hershey area and across the state.

Ticks typically need to be attached for 36 to 48 hours before they can transmit Borrelia burgdorferi to a dog. This is why checking your dog for ticks after every outdoor outing is one of the most effective ways to reduce risk.

Where Are Dogs Most Likely to Pick Up Ticks?

Dogs encounter ticks most often in wooded areas, tall grass, and brushy environments where deer and small rodents (which host ticks in their early life stages) are common. In central Pennsylvania, this includes:

• Wooded trails and state parks
• Backyards with leaf litter or tall grass
• Open fields and meadows
• Areas near water where wildlife congregates

Symptoms of Lyme Disease in Dogs

One of the most challenging things about Lyme disease in dogs is that many infected dogs show no symptoms at all, or symptoms appear weeks to months after the original tick bite. When signs of Lyme disease do appear in dogs, they can include:

• Lameness that shifts from leg to leg (a hallmark symptom of Lyme disease in dogs)
• Joint swelling and pain
• Fever
• Lethargy and decreased activity
• Loss of appetite
• Swollen lymph nodes

Unlike in humans, dogs with Lyme disease rarely develop the classic “bull’s-eye” rash. Because Lyme disease symptoms in dogs mimic other conditions, a veterinary diagnosis is essential.

What Is Lyme Nephritis in Dogs?

A severe and potentially fatal complication of Lyme disease in dogs is Lyme nephritis, which is kidney disease triggered by the immune response to Borrelia burgdorferi. Lyme nephritis tends to progress rapidly and is most commonly seen in Labrador Retrievers and Golden Retrievers, though any dog can be affected. Signs include vomiting, weight loss, increased thirst and urination, swelling in the legs, and loss of appetite. Dogs with these symptoms need emergency veterinary attention immediately.

How Is Lyme Disease Diagnosed in Dogs?

Veterinarians typically diagnose Lyme disease in dogs using a combination of history, physical examination, and blood testing. The most common screening test is a 4Dx or similar snap test that detects antibodies to Borrelia burgdorferi. A positive result indicates exposure to the bacterium, though further testing may be needed to confirm active infection.

Your veterinarian may also run bloodwork and urinalysis to assess kidney function, especially if Lyme nephritis is a concern. If you’re in the Hershey area and suspect your dog may have been exposed to ticks or is showing signs of Lyme disease, Hershey Animal Emergency Center can perform the necessary diagnostics and connect you with appropriate care.

Treatment Approach for Lyme Disease in Dogs

The standard treatment for Lyme disease in dogs involves a course of antibiotics, most commonly doxycycline, typically prescribed for 30 days. Most dogs with Lyme disease respond well to treatment and show significant improvement within the first few days of starting antibiotics.

However, Lyme disease treatment in dogs doesn’t always eliminate the infection entirely. Some dogs remain seropositive (continue to test positive for antibodies) even after treatment, and in a small number of cases, clinical signs can recur. This is why follow-up testing and monitoring are an important part of managing Lyme disease in dogs long-term.

What Happens If Lyme Disease in Dogs Goes Untreated?

Untreated Lyme disease in dogs can lead to serious complications, including chronic joint pain, kidney damage, and in rare cases, heart or neurological problems. Lyme nephritis, mentioned above, is the most feared complication because it can progress to kidney failure quickly. This is why early treatment matters. Don’t wait to see if symptoms resolve on their own.

How to Prevent Lyme Disease in Dogs

Prevention is the most powerful tool against Lyme disease in dogs. A multi-layered approach works best:

• Tick prevention products: Topical treatments, oral medications, and tick collars recommended by your veterinarian are highly effective at killing and repelling ticks before they can transmit disease.
• Lyme disease vaccination: A vaccine for Lyme disease is available for dogs and is recommended by many veterinarians in high-risk regions like Pennsylvania. Talk to your vet about whether it’s right for your dog.
• Tick checks after outdoor activities: Inspect your dog’s skin and coat after every walk, hike, or yard play session, paying special attention to the ears, neck, groin, and between the toes.
• Yard maintenance: Keep grass mowed and remove leaf litter to reduce tick habitat around your home.

When to Take Your Dog to the Emergency Vet for Lyme Disease

If your dog is showing signs of sudden lameness, joint pain, fever, or decreased appetite, especially after spending time outdoors in wooded or grassy areas, it’s worth calling a veterinarian as soon as possible. Lyme disease in dogs is treatable, but outcomes are best when care begins early.

At Hershey Animal Emergency Center in Hershey, PA, our team is here for your dog when your primary vet is unavailable. Call us now at (717) 298-7883 for guidance. Whether you’ve found a tick on your dog or you’re concerned about possible Lyme disease symptoms, we’re ready to help you get answers and a care plan.