FR
ENWhat is IMHA?
Immune-mediated hemolytic anemia (IMHA), also called autoimmune hemolytic anemia, occurs when the immune system overreacts and destroys the dog's own red blood cells (RBCs) prematurely. The loss of RBCs reduces the body's ability to transport oxygen throughout the body, which can cause serious breathing difficulties and, without treatment, be life-threatening.
Primary / idiopathic IMHA
No identifiable cause. The immune system attacks red blood cells without a known external trigger. May have a genetic component; certain breeds (Cocker Spaniels, Springer Spaniels, Poodles) are at higher risk.
Secondary IMHA: medications & vaccines
Certain medications or vaccinations alter the surface of red blood cells, triggering an exaggerated immune response. Dogs that have suffered from IMHA may be exempt from certain future vaccinations.
Secondary IMHA : infections & parasites
Bacterial, viral, or parasitic infections (tick-borne diseases, ehrlichiosis, babesiosis, etc.) can trigger or worsen IMHA by altering the surface of red blood cells.
Evans syndrome
Simultaneous combination of IMHA with immune-mediated thrombocytopenia (IMT), the immune system destroys both red blood cells and platelets. More guarded prognosis and more complex treatment.
A related condition, immune-mediated thrombocytopenia (IMT), occurs when the immune system attacks platelets. IMT and IMHA can coexist (Evans syndrome) or appear separately.
Signs and symptoms
IMHA signs can appear suddenly or develop gradually over several days. The rate of progression is variable; rapid deterioration is possible, making prompt veterinary consultation essential when in doubt.
Early stage
- •Mild to moderate weight loss
- •Intermittent vomiting and diarrhea
- •Fluctuating loss of appetite
- •Weakness, reduced activity, less interested in play
- •Dull, unkempt coat
- •Spontaneous bruising (if IMT is also present)
Intermediate stage
- •Jaundice (icterus): yellow gums and whites of eyes
- •Panting, rapid breathing
- •Collapse or marked exercise intolerance
- •Bloody diarrhea
- •Distended abdomen, possible ascites
Advanced stage
- •Trembling, profound weakness, extreme lethargy
- •Whimpering or vocalizing in pain
- •Dark-colored urine (bilirubinuria or hemoglobinuria)
- •Very pale or white mucous membranes
- •Seizures (rare, sign of severe hypoxia)
When to seek immediate help?
IMHA can rapidly become a life-threatening emergency. Go immediately to a veterinarian or emergency clinic if you observe:
- Respiratory distress: intense panting, difficulty breathing, mouth breathing
- Bluish, very pale, or white gums or tongue (cyanosis or severe anemia)
- Sudden collapse or inability to stand
- Uncontrollable vomiting or bloody diarrhea
- Intense pain: constant whimpering, very tense abdomen
- Dark tea-colored urine or blood in the urine
How is the diagnosis made?
Diagnosis can be challenging. It relies on a combination of clinical signs, bloodwork, and a search for an underlying cause, which can itself be difficult to identify.
Clinical signs and bloodwork
Low hematocrit (moderate to severe anemia), elevated white blood cell count (inflammation), elevated liver enzymes (RBC destruction). The presence of spherocytes on a blood smear is a characteristic sign of IMHA.
Confirmatory tests
Direct Coombs test to detect antibodies bound to red blood cells. Blood smear to visualize spherocytes and signs of hemolysis. These tests confirm the immune origin of RBC destruction.
Search for underlying causes
Serology for tick-borne diseases (ehrlichiosis, babesiosis, anaplasmosis). Abdominal ultrasound and chest X-ray to screen for tumors. Biopsies or advanced imaging (CT scan, MRI) based on initial results.
Treatment and management
Treatment is based on immunosuppression to stop RBC destruction, emergency stabilization when anemia is severe, and management of any identified underlying cause.
- Corticosteroids (prednisone): the cornerstone of treatment: suppress the immune attack on RBCs. High initial doses, then gradual tapering over several months.
- Other immunosuppressants: azathioprine, cyclosporine, mycophenolate mofetil: added when response to corticosteroids alone is insufficient.
- Duration: several months of immunosuppressive treatment with gradual dose reduction once the condition stabilizes.
- Blood transfusions: whole blood or packed red blood cells for life-threatening severe anemia: stabilizes the dog while immunosuppressants take effect.
- Anticoagulants: heparin or low-dose aspirin: reduce the risk of thrombosis, a frequent complication of IMHA.
- Supportive care: liver supplements, antacids (against steroid-induced hyperacidity), probiotics for gut health.
- Treating the cause: if a tumor, infection, or triggering medication is identified, prompt management can significantly improve IMHA outcomes.
- Regular monitoring: frequent bloodwork to monitor hematocrit, platelet count, and immunosuppressant side effects.
- Vaccine exemption: dogs in remission may benefit from a veterinary exemption letter to avoid vaccinations that could trigger a relapse.
What to expect long-term?
Short-term prognosis depends primarily on speed of response to treatment and severity of anemia. The first two weeks are critical.
A personalized care plan, sometimes including consultation with a specialist (veterinary internist or immunologist), is often the best strategy for long-term IMHA management.
Home management tips
To implement
- Administer all medications rigorously, at prescribed doses and times
- Plan prescription refills in advance, never stop abruptly
- Check gum color daily (pale pink or white = emergency)
- Place non-slip surfaces (rugs) to prevent falls if the dog is weak
- Install ramps or small steps if the dog has difficulty climbing up or down
- Offer regular meals in small portions to monitor appetite
- Monitor energy, thirst, appetite, and urine color every day
- Minimize stress (avoid unnecessary travel, noisy environments)
- Obtain a vaccination exemption letter if recommended by the veterinarian
Never do
- Adjust immunosuppressant doses without veterinary guidance
- Abruptly stop prednisone or any other immunosuppressant
- Administer vaccines without prior discussion with the veterinarian
- Give human pain or anti-inflammatory medications without a prescription
Always
- Maintain regular veterinary follow-up with bloodwork
- Report any signs of relapse immediately (paleness, weakness, jaundice)
- Keep the vaccination exemption letter in the dog's medical file
Frequently asked questions
IMHA: does my dog really make antibodies against itself?
Why does my dog need a blood transfusion?
Are immunosuppressant medications dangerous?
Will my dog be cured after treatment?
Is it really necessary to avoid vaccines in the future?
This guide is provided for informational and educational purposes only. It does not constitute veterinary medical advice and is not a substitute for a consultation with a qualified veterinarian. Every animal is unique and their health must be evaluated individually. If you have concerns about your pet's health, contact our clinic or consult a veterinarian promptly.
Is your dog showing signs of IMHA?
IMHA requires prompt management. Our veterinary team is available to evaluate your dog and start appropriate treatment without delay.