What Is Ehrlichiosis in Dogs? (Tick-Borne Infection)

Start here. If your dog has a nosebleed that will not stop, bleeding from the gums, mouth or rectum, pale or white gums, sudden weakness or collapse, laboured breathing, a seizure, sudden vision loss, or a red, cloudy or painful eye, go to an emergency veterinary clinic now. If your dog has a fever, is flat and lethargic, has stopped eating, is stiff or shifting lame, or you have found a tick and something seems off, call your veterinarian the same day and ask specifically about testing for tick-borne disease. Ehrlichiosis can also be silent, so a low platelet count found on routine bloodwork deserves a follow-up conversation rather than a wait-and-see.

Ehrlichiosis in dogs is a tick-borne bacterial infection caused by organisms in the genus Ehrlichia, which are carried by ticks and live inside a dog's white blood cells once they are transmitted through a bite. The two words owners see together mean slightly different things: Ehrlichia is the bacterium, and ehrlichiosis is the disease state it produces. The form diagnosed most often in dogs is caused by Ehrlichia canis, which targets monocytes, a type of circulating white blood cell. Yes, dogs can get ehrlichiosis, and they get it only through a tick, not from another dog, not from a person, and not from a shared water bowl.

What makes this infection hard for owners is that it does not behave like a kennel cough or a skin infection. It can arrive with an obvious fever and a nosebleed, or it can slip into a quiet phase where the dog looks completely normal for months while the organism persists in the body. That is why so many dogs are first flagged by a routine blood panel rather than by a sick day.

How dogs pick up Ehrlichia

The cause is always the same: an infected tick attaches, feeds, and passes the organism into the dog's bloodstream. Different Ehrlichia species travel with different ticks. Ehrlichia canis, the agent of canine monocytic ehrlichiosis, is carried by the brown dog tick, Rhipicephalus sanguineus. Ehrlichia ewingii, which infects neutrophils rather than monocytes, and Ehrlichia chaffeensis are both associated with the lone star tick, Amblyomma americanum.

A few practical points follow from that biology. Ticks do not need deep woods. The brown dog tick is unusual in that it can complete its entire life cycle indoors, which means kennels, garages and homes can hold a population once it establishes. Transmission does not require a tick to feed for days either, so finding and removing ticks quickly is genuinely protective rather than cosmetic.

Signs, when they appear, usually show up a week or two after the bite, though the window varies with the dog and the organism. Infection can also be passed through a blood transfusion from an infected donor, which is one reason blood banks screen donors for tick-borne agents.

Is it common? In regions where those vector ticks are established, ehrlichiosis is one of the tick-borne infections veterinarians diagnose and screen for most routinely, alongside Lyme disease and anaplasmosis. Prevalence varies widely by area, by season and by how much testing is being done, so the useful question is not a national percentage but a local one: ask your veterinarian how often they see positive Ehrlichia results in your area and whether your dog's lifestyle puts them in contact with the right ticks.

The three stages of infection and what each one looks like

The Merck Veterinary Manual describes canine monocytic ehrlichiosis as moving through three recognised phases. Not every dog passes through all of them, and many are caught and managed in the first.

Stage	What is happening inside the dog	What an owner may actually see
Acute	The organism replicates in white blood cells, inflammation affects small blood vessels, and platelets are consumed or destroyed faster than they are made	Fever, lethargy, loss of appetite, enlarged lymph nodes, stiffness or lameness, occasional nosebleed or pinpoint bruising
Subclinical	The immune system holds the infection in check but does not always clear it; organisms can persist, often in the spleen	Usually nothing at all; the dog looks and acts normal, while bloodwork may show a mildly low platelet count or elevated globulins
Chronic	Bone marrow function becomes suppressed and immune complexes damage small vessels, eyes and kidneys	Weight loss, pale gums, bleeding that is hard to stop, cloudy or painful eyes, swelling in the limbs, neurologic signs

German Shepherd Dogs are reported in the veterinary literature to be more prone to the severe chronic form, which is worth mentioning to your veterinarian if that is your breed.

Nosebleeds, bruising and the other symptoms owners notice

The symptom that sends the most owners searching at midnight is a nosebleed. Epistaxis in ehrlichiosis is not a nasal problem in the usual sense. It reflects what the infection does to platelets and to the lining of small blood vessels: platelet numbers drop, the platelets that remain may not function normally, and vessel walls become inflamed. Blood then escapes where it normally would not, which is also why owners sometimes notice pinpoint red spots on the gums or belly, unexplained bruising, or blood in the urine or stool.

If your dog has an unexplained nosebleed, new bruising, or a low platelet count on a blood panel, ask your veterinarian directly about testing for tick-borne disease.

The other signs cluster around a dog that simply feels unwell: fever that comes and goes, flat energy, a dog that walks away from dinner, swollen lymph nodes under the jaw, and stiffness or shifting lameness that can be mistaken for an orthopaedic problem. Eye involvement is well recognised, including uveitis, a painful inflammation inside the eye that can show as squinting, redness, cloudiness or sudden changes in vision.

Owners often search for the side effects of ehrlichiosis in dogs. What they usually mean is the downstream damage the infection can leave behind: protein loss through the kidneys from immune complex injury, persistent joint pain, muscle loss in dogs that have been inactive and unwell for weeks, anaemia, and in the chronic form, suppression of all three blood cell lines.

Neurologic signs are less common but real. Inflammation around the brain and spinal cord, or bleeding into the central nervous system when platelets are very low, can produce wobbliness, head tilt, neck pain and, in some dogs, seizures. A seizure is an emergency regardless of cause, so that is a same-day call rather than a wait-and-see.

When there are no symptoms at all

A dog can carry Ehrlichia and look perfectly healthy. The subclinical phase is exactly that: a normal dog, a normal appetite, a normal walk, and an organism still present. Some dogs clear the infection on their own. Others hold it quietly for months or longer, and a subset go on to develop chronic disease.

This is why screening matters and why the diagnosis so often begins with a blood count rather than a symptom. A low platelet count is the most consistently reported abnormality in infected dogs, and elevated globulins are another common clue. From there, veterinarians typically use in-clinic antibody screening tests, laboratory antibody titres, and PCR, which looks for the organism's DNA rather than the immune response to it.

Timing matters when interpreting results. Antibodies take time to develop after a bite, so a dog tested very early can be negative and still be infected. Antibodies can also stay positive long after the infection has been addressed, which means a positive test is read alongside the dog's clinical picture and bloodwork, not in isolation. Your veterinarian is the one who puts those pieces together, and that interpretation is the whole job here.

After the diagnosis, and the long road back to normal movement

Treatment is veterinary territory. Your vet may prescribe medication for a defined course, and dogs that are severely affected may also need fluids, hospitalisation or transfusion support. Nothing in this article should be read as a reason to delay, shorten or stop anything your veterinarian has prescribed. Finish the course exactly as directed and keep the recheck appointments, because the follow-up bloodwork is how progress is actually measured.

What owners are often less prepared for is the recovery that follows. A dog who has run a fever, stopped eating and barely moved for weeks does not simply switch back on. Muscle mass comes off faster than it goes back on, joints that were sore from inflammation stay stiff, and tendons and soft tissue that have been under-loaded need gradual, structured reloading rather than a sudden return to the park. Ask your veterinarian when and how to restart exercise, and whether a rehabilitation plan makes sense for your dog. Results vary from dog to dog, and the pace of recovery depends on how long the dog was unwell and what else the bloodwork shows.

What to watch at home

Once a diagnosis is made, your job at home is observation, not improvisation. The most useful things to track are simple and concrete:

• Gum colour. Lift the lip once or twice a day and look. Healthy gums are pink and moist. Pale, white, grey or yellow gums, or pinpoint red spots and bruise-like patches, are reasons to call straight away.
• Bleeding of any kind. Nosebleeds, blood in urine or stool, blood in vomit, bruising that appears without an injury, or a small cut that keeps oozing.
• Appetite and water intake. Note whether your dog is eating normally, picking, or refusing food entirely, and whether drinking and urination have noticeably increased.
• Energy and movement. Is the dog getting up willingly, or stiff, reluctant, shifting lame, or unsteady on the back end?
• Temperature swings. Owners cannot always tell, but a dog that is shivering, seeking cool floors or hot to the touch at the ears and groin may be running a fever. Ask your vet whether home temperature checks are appropriate for your dog and how to do them safely.
• Eyes. Squinting, redness, cloudiness, a changed pupil, bumping into furniture or hesitation on stairs can all point to eye involvement and should be seen promptly.
• Breathing. Faster, harder or noisier breathing at rest is never a wait-and-see finding.

A short daily note on your phone is enough. Patterns over several days are far more useful to a veterinarian than a single impression on the day of the appointment.

What to note and tell your vet

Walking in with specifics changes how quickly the right tests get run. Useful details include:

• When you last found a tick on your dog, where on the body it was, and roughly how long it may have been attached.
• What tick prevention your dog is on, when it was last given or applied, and whether any doses were missed.
• Where your dog has been: travel, boarding, kennels, hunting, hiking, or a home or garage where ticks may be established.
• When the appetite, energy or movement first changed, and whether it has been steady, worsening, or coming and going.
• Every episode of bleeding or bruising you have seen, including ones that seemed minor.
• Any previous tick-borne test results, previous blood panels, or past episodes of unexplained lameness or fever.
• Everything your dog currently receives, including food, chews, topicals and anything given by another household member.

If your dog is already being treated, bring the recheck history and tell your vet about any day when a dose was missed or vomited, any new sign that appeared after treatment started, and anything that has not improved the way you expected.

When it becomes an emergency

Some signs should not wait for the next available appointment. Go to an emergency clinic if you see:

• Bleeding that will not stop, or heavy or repeated nosebleeds.
• Pale, white or grey gums, weakness, wobbliness or collapse.
• Laboured, fast or open-mouth breathing at rest.
• A seizure, severe neck pain, a head tilt, circling or sudden disorientation.
• Sudden blindness, or a painful, bulging, red or cloudy eye.
• A dog that cannot stand, will not rise, or is unresponsive.
• Repeated vomiting, a swollen or painful abdomen, or complete refusal of food and water.

If you are unsure whether a sign qualifies, phone the clinic and describe exactly what you are seeing. Triage advice over the phone costs nothing and is what reception and nursing staff are there for.

Key Takeaways

• Ehrlichiosis in dogs is a tick-borne bacterial infection; Ehrlichia is the organism, ehrlichiosis is the disease it causes.
• Dogs get it only from an infected tick, most often the brown dog tick carrying Ehrlichia canis, or through an infected blood transfusion.
• Classic acute signs are fever, lethargy, appetite loss, swollen lymph nodes, bruising and nosebleeds driven by low or poorly functioning platelets.
• Many infected dogs show no symptoms at all and are first identified by a low platelet count on routine bloodwork.
• Eye inflammation, kidney protein loss, joint pain and, less commonly, neurologic signs including seizures are recognised complications.
• Uncontrolled bleeding, pale gums, collapse, seizures, breathing difficulty or sudden eye changes are emergencies.
• Diagnosis combines bloodwork with antibody testing and PCR, and timing affects how results are interpreted.
• Prevention is unglamorous and effective: vet-recommended tick prevention, daily tick checks, and prompt tick removal.

Where to go from here

If any of this matches your dog, the next step is a veterinary appointment and a blood panel, not a search result. Bring specifics: when you last found a tick, what prevention your dog is on, when the appetite or energy changed, and any bleeding you have seen. Those details shape which tests get run first.

Between appointments, keep the home record simple and consistent: appetite, energy, gum colour, any bleeding, any change in movement or vision. Take a photo of anything visible, such as bruising, a swollen limb or a reddened eye, since signs often fade by the time you reach the clinic. Keep copies of bloodwork so changes can be compared over time, and ask what specific findings your vet wants to recheck and what would count as a reason to come back sooner.

Your veterinarian owns the diagnosis, the prescription and the recheck schedule for ehrlichiosis. Nothing in this article treats, cures or prevents any condition; every decision about your dog's care belongs with your veterinarian.

Related guides: Senior Dog Bloodwork : What a Senior Blood Panel Shows.