Ehrlichiosis in Dogs: Tick-Borne Disease Guide
- Ehrlichiosis is a tick-borne bacterial infection in dogs, most often linked to Ehrlichia canis and Ehrlichia ewingii. In the US, brown dog ticks and lone star ticks are the main vectors.
- Common signs include fever, tiredness, poor appetite, swollen lymph nodes, bruising, nosebleeds, and low platelets. Some dogs look normal during a subclinical phase before becoming sick later.
- Diagnosis usually combines a tick-borne disease screening test, complete blood count, chemistry panel, and sometimes PCR testing. Low platelets are one of the most common lab findings.
- Doxycycline is the usual first-line treatment, often given for about 28 days. Many dogs improve quickly in the acute phase, but chronic cases can be more serious and may need hospitalization.
- Typical cost range is about $250-$800 for uncomplicated outpatient care and $1,500-$5,000+ for severe chronic disease with transfusions, intensive monitoring, or referral care.
What Is Ehrlichiosis?
Ehrlichiosis is a tick-borne bacterial infection that affects dogs' white blood cells. The best-known form is caused by Ehrlichia canis, which infects monocytes and can lead to canine monocytic ehrlichiosis. Other species, including Ehrlichia ewingii, can also infect dogs and may cause somewhat different signs, such as fever, stiffness, or joint pain.
After a dog is infected, illness may move through acute, subclinical, and chronic phases. In the acute phase, dogs may develop fever, lethargy, enlarged lymph nodes, bruising, or appetite loss within about 1 to 3 weeks after infection. Some dogs then enter a subclinical phase, where they seem normal but still carry evidence of infection on testing.
The chronic phase is the most concerning. In some dogs, especially those with more severe disease, ehrlichiosis can contribute to bone marrow suppression, anemia, low platelets, bleeding problems, eye inflammation, kidney involvement, or neurologic signs. That is why early testing and follow-up matter, even if your dog seems to perk up on their own.
This condition is treatable, but the outlook depends on how early it is found, how sick the dog is at diagnosis, and whether there are co-infections or complications. Your vet can help match the workup and treatment plan to your dog's symptoms, bloodwork changes, and your family's goals.
Symptoms of Ehrlichiosis
- Fever, often early in the acute phase
- Lethargy, weakness, or reduced stamina
- Loss of appetite or gradual weight loss
- Enlarged lymph nodes or enlarged spleen
- Bruising, petechiae, or bleeding under the skin from low platelets
- Nosebleeds, bleeding gums, or prolonged bleeding after minor injury
- Pale gums from anemia
- Eye inflammation, discharge, or cloudiness
- Lameness, stiffness, or joint pain, especially with E. ewingii infection
- Vomiting, diarrhea, or general malaise in some dogs
- Neurologic signs such as wobbliness, head tilt, or seizures in severe cases
- Collapse, uncontrolled bleeding, or marked weakness in advanced disease
Symptoms can be mild at first and then become more serious. Some dogs only show vague signs like tiredness and poor appetite, while others develop bruising, nosebleeds, or pale gums because their platelet count or red blood cell count has dropped. Dogs in a subclinical phase may look normal even though bloodwork is abnormal.
See your vet immediately if your dog has unexplained bleeding, pale gums, collapse, trouble walking, or severe weakness, especially after known tick exposure. If your dog has had ticks recently, tell your vet when and where that happened. That history can help guide testing.
What Causes Ehrlichiosis?
Ehrlichiosis is caused by Ehrlichia bacteria spread through the bite of an infected tick. In US dogs, Ehrlichia canis is classically associated with the brown dog tick (Rhipicephalus sanguineus), while Ehrlichia ewingii is associated with the lone star tick (Amblyomma americanum). These ticks are found in many parts of the country, with higher risk in the southeastern, south-central, and some southwestern regions.
Dogs are more likely to be exposed if they spend time in brush, tall grass, wooded edges, kennels, shelters, or homes with tick infestations. Brown dog ticks are especially important because they can complete much of their life cycle indoors, which means exposure is not limited to hiking dogs.
Risk is higher in dogs without consistent tick prevention and in dogs living where tick-borne disease is common. German Shepherd Dogs have been reported to be at higher risk for severe chronic disease. Co-infections with other tick-borne organisms can also make illness more complicated.
Dogs do not usually spread ehrlichiosis directly to each other through casual contact. Rarely, infection can be transmitted through a blood transfusion from an infected donor. People do not catch ehrlichiosis directly from dogs, but they can be exposed to related organisms from tick bites in the same environment.
How Is Ehrlichiosis Diagnosed?
Diagnosis usually starts with a history of tick exposure, symptoms, and bloodwork. A complete blood count (CBC) often shows thrombocytopenia, or low platelets, which is one of the most common findings. Your vet may also recommend a chemistry panel and urinalysis to look for anemia, protein changes, kidney involvement, or other organ effects.
Many clinics use an in-house SNAP 4Dx-style screening test as part of the initial workup. This test looks for antibodies, which means it can show exposure but does not always prove active infection. Early in disease, a dog may test negative before antibodies have had time to develop. A positive result also can persist after treatment, so it is not a perfect "cure check."
A PCR test can help detect Ehrlichia DNA and may be especially useful in some acute cases, complicated cases, or when your vet wants species-level confirmation. In dogs with severe anemia, very low blood cell counts, or concern for chronic marrow disease, your vet may discuss bone marrow sampling or referral testing.
Typical diagnostic cost ranges in the US are about $150-$450 for an exam plus screening bloodwork and $90-$220 more for PCR, depending on region and lab. More advanced workups can raise the total meaningfully, especially if imaging, referral care, or repeat testing is needed.
Treatment Options for Ehrlichiosis
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Focused outpatient care
- Office exam and tick exposure history review
- CBC with or without chemistry panel
- In-clinic tick-borne disease screening test
- Doxycycline course, commonly about 28 days
- Basic anti-nausea or probiotic support if GI upset develops
- One follow-up recheck and repeat CBC
- Discussion of year-round tick prevention
Comprehensive diagnosis and monitored treatment
- Exam plus CBC, chemistry panel, and urinalysis
- In-clinic screening plus send-out PCR when indicated
- Doxycycline treatment with dose adjustments guided by your vet
- Repeat bloodwork during and after treatment
- Assessment for co-infections such as Anaplasma or Lyme exposure
- Supportive medications for nausea, pain, or appetite as needed
- Structured tick prevention plan and environmental control advice
Hospitalization and critical care for severe or chronic disease
- Hospitalization with intensive monitoring
- Expanded lab work, coagulation testing, and referral diagnostics
- IV fluids and supportive nursing care
- Blood product support such as packed red cells or plasma when needed
- Management of severe bleeding, profound anemia, or pancytopenia
- Bone marrow evaluation or specialist consultation in selected cases
- Longer-term rechecks after discharge
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Ehrlichiosis
Bring these questions to your vet appointment to get the most out of your visit.
- Do my dog's signs and bloodwork fit acute, subclinical, or chronic ehrlichiosis? The phase of disease helps guide urgency, monitoring, and prognosis.
- How low are my dog's platelets and red blood cells right now? Those numbers help you understand bleeding risk, anemia severity, and whether outpatient care is reasonable.
- Should we run PCR or other tests to confirm active infection or look for co-infections? Some dogs have more than one tick-borne disease, and that can change the treatment plan.
- What side effects should I watch for while my dog is taking doxycycline? GI upset, poor appetite, or trouble giving medication can affect whether treatment is completed successfully.
- When should we repeat bloodwork, and what changes would make you want to escalate care? A clear recheck plan helps catch persistent thrombocytopenia, anemia, or worsening disease early.
- Does my dog need activity restriction while platelets are low? Dogs with thrombocytopenia may need a quieter routine to reduce bruising or bleeding risk.
- What tick prevention product fits my dog's age, lifestyle, and health history? Prevention is the best way to reduce the risk of reinfection.
How to Prevent Ehrlichiosis
The most effective prevention is consistent tick control all year, especially in areas where ticks are active for much of the year or where brown dog ticks can survive indoors. Your vet can help you choose an oral, topical, or collar-based product that fits your dog's age, health status, and lifestyle.
Check your dog for ticks after walks, yard time, hunting, camping, or travel. Pay close attention to the ears, neck, between the toes, under the collar, armpits, groin, and around the face. Prompt removal matters. Use a tick-removal tool or fine-tipped tweezers, grasp close to the skin, and pull steadily without twisting.
Home and yard management also help. Keep grass trimmed, reduce brush and leaf litter, and address indoor infestations quickly if brown dog ticks are found. If one pet has ticks, ask your vet whether all pets in the household need prevention or environmental treatment.
There is no vaccine for canine ehrlichiosis. Screening may still be useful, especially in dogs with tick exposure or vague signs like lethargy, bruising, or poor appetite. If your dog tests positive but feels well, your vet can help decide whether monitoring, additional testing, or treatment makes the most sense.