Ehrlichiosis in Dogs: Symptoms, Stages, Treatment and Prognosis

What Causes Ehrlichiosis in Dogs?

Several species of Ehrlichia bacteria infect dogs. Each is carried by particular ticks:^2,1

• Ehrlichia canis causes canine monocytic ehrlichiosis, the classic form, which can become chronic. It is spread mainly by the brown dog tick, which can live and breed indoors in homes and kennels.^2,3
• Ehrlichia ewingii causes granulocytic ehrlichiosis, which often shows up as lameness and joint pain. It is spread by the lone star tick.^2,1
• Ehrlichia chaffeensis, also spread by the lone star tick, mainly causes illness in people. Dogs can be infected and can carry it without signs.²

Where it occurs: E. canis is found on every continent except Australia and Antarctica. In North America, most cases are in the southeastern and southwestern U.S. E. ewingii follows the lone star tick's range in the southeastern and south-central states.² Dogs with heavy tick exposure and no tick prevention, such as dogs in kennels, are at higher risk.¹

How fast it spreads: Ehrlichia can be passed on within about 3 to 6 hours of a tick attaching, much faster than the 24 to 48 hours usually needed for Lyme disease, so a preventive that kills or repels ticks quickly is important.³ Infected dogs should not be used as blood donors.^1,2

Symptoms of Ehrlichiosis in Dogs

Some infected dogs show no signs at all. Others develop acute (short-term) illness, and some go on to a chronic form.¹

E. canis (monocytic ehrlichiosis)

• Fever, low energy and a poor appetite
• Bleeding: nosebleeds, bruising, pinpoint red spots on the gums or skin, and black, tarry stool
• Pale gums from anemia
• Swollen lymph nodes and an enlarged spleen
• Eye problems and neurological signs in some dogs^1,2

E. ewingii (granulocytic ehrlichiosis)

• Lameness that shifts between legs, stiffness and swollen joints
• Muscle pain, fever, lethargy and a reduced appetite^1,2

The Three Stages of E. canis Infection

• Acute phase: signs usually appear 1 to 2 weeks after the tick bite, and the acute phase lasts about 1 to 4 weeks. With proper treatment, dogs may recover fully.¹
• Subclinical phase: some dogs carry the infection without obvious signs.^2,1
• Chronic phase: in untreated or inadequately treated dogs, infection can last months to years. The chronic form is uncommon but serious. The bone marrow stops producing enough blood cells, and the immune reaction can damage the eyes, muscles, blood vessels and kidneys. German Shepherds appear more likely to develop it.^1,2

Diagnosis

• History and exam: your vet will ask about tick exposure and travel.¹
• Blood count and chemistry: a low platelet count and mild anemia are common with E. canis, and high blood protein (globulin) levels are typical. Chronic cases may show low counts of all blood cells.²
• Antibody tests: quick in-clinic tests and lab tests detect antibodies, but they can take up to 4 weeks to turn positive, and they can't tell the Ehrlichia species apart.²
• PCR testing detects the organism's DNA. It can identify the species and help show whether an infection is still active.^2,1

Many dogs stay antibody-positive for months to years after successful treatment, so a positive test on its own doesn't always mean active disease.^1,2 See also our guide to dog blood tests.

Treatment of Ehrlichiosis in Dogs

• Doxycycline is the drug of choice, usually given for 28 days. Minocycline is an alternative.²
• Start early: vets often begin treatment while test results are pending, because early antibody tests can be negative.²
• Response: fever usually improves within 24 to 48 hours of starting treatment. Blood count changes in chronic cases can take 3 to 6 months to return to normal.²
• Supportive care: dogs with severe bleeding or anemia may need hospital care and blood or platelet transfusions.^2,4
• Chronic infection may need months of treatment and ongoing monitoring.¹

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.⁵

Prognosis: Can Dogs Recover From Ehrlichiosis?

Yes. The outlook is excellent for most dogs that are treated promptly.¹ Most acute infections resolve within weeks.² The outlook is guarded for dogs with chronic E. canis infection, especially when the bone marrow is affected.¹ Dogs that don't respond as expected should be checked for other tick-borne infections, such as Babesia.¹

Can People Get Ehrlichiosis From Dogs?

No. People get ehrlichiosis from tick bites, not directly from dogs. But dogs can carry ticks into the home, so check yourself for ticks too.^1,2

Preventing Ehrlichiosis

• Year-round tick control: use a vet-recommended tick preventive consistently, all year, and adjust it to where you live and travel.^3,1
• Prompt tick removal: check your dog after time outdoors and remove ticks with fine-tipped tweezers, grasping close to the skin and pulling slowly and steadily.³ See our guide to removing ticks from dogs.
• Watch for brown dog ticks indoors: infestations in homes and kennels can take months to clear and usually need a professional pest-control service, along with consistent treatment of every pet.³
• Take extra care in kennels and boarding facilities, where tick exposure can be high.¹

Prevention relies on tick control. For product options, see our guide to tick prevention for dogs, plus our pages on tick diseases in dogs and tick pictures.

Frequently Asked Questions

How serious is ehrlichiosis in dogs?

It ranges from no signs to life-threatening illness. Most dogs treated promptly recover fully, but untreated infection can become chronic and damage the bone marrow, which carries a more guarded outlook.

Can dogs fully recover from Ehrlichia?

Yes. Most dogs treated promptly with doxycycline recover well. Dogs with chronic infection have a more guarded outlook and may need months of treatment.

What is the survival rate for dogs with ehrlichiosis?

There is no single survival figure, but the prognosis is excellent for most dogs treated early. It is guarded for chronic cases with bone marrow suppression.

What if my dog tests positive for Ehrlichia?

A positive antibody test shows exposure. Your vet will check for signs of illness and blood count changes, and may run a PCR test to see whether the infection is active, before deciding on treatment.

Will my dog always test positive for Ehrlichia?

Possibly for a long time. Many dogs stay antibody-positive for months to years after successful treatment, so PCR testing and blood counts help show whether the infection is still active.

Is ehrlichiosis the same as Lyme disease?

No. Both are tick-borne bacterial infections, but ehrlichiosis is caused by Ehrlichia and spread mainly by brown dog ticks and lone star ticks, while Lyme disease is caused by Borrelia burgdorferi and spread by black-legged (deer) ticks. Both are treated with antibiotics, most often doxycycline.

Can dogs pass ehrlichiosis to humans?

No. People catch ehrlichiosis from tick bites, not from dogs. Dogs can bring ticks into the home, though, so tick control on pets helps protect the family.

How is ehrlichiosis treated in dogs?

With the antibiotic doxycycline, usually for 28 days, plus supportive care such as transfusions for severe bleeding or anemia. Fever usually improves within 1 to 2 days.