Dog Immune-Mediated Haemolytic Anaemia

Immune-mediated haemolytic anaemia (IMHA) is a life-threatening condition in dogs requiring rapid diagnosis and immunosuppressive treatment.

Key Facts

IMHA occurs when the immune system attacks and destroys red blood cells; the trigger is often unknown.
Cocker Spaniels, Springer Spaniels, and Irish Setters are predisposed breeds.
Clinical signs include pale gums, rapid breathing, profound lethargy, and collapse.
Treatment involves high-dose corticosteroids and often additional immunosuppressants such as mycophenolate.
Mortality rates of 20-50% are reported; thromboembolism (blood clots) is the most serious complication.

Welfare Considerations

IMHA causes acute, severe anaemia that can progress to life-threatening cardiovascular compromise within hours. Affected dogs experience profound weakness, breathlessness, and in severe cases collapse. Blood transfusions provide emergency support while immunosuppressive therapy takes effect. The treatment itself — high-dose corticosteroids — causes side effects including polydipsia, polyuria, and muscle wasting that impair comfort. Thromboembolism can cause sudden death or severe pain from vessel blockage. Survivors require months of medication tapering and face a significant relapse risk. Welfare management requires intensive hospitalisation followed by close outpatient monitoring and honest conversations about prognosis.

What You Can Do

Seek emergency veterinary care immediately for any dog showing sudden weakness, pale gums, or collapse.
Understand the serious prognosis and welfare implications of IMHA treatment before beginning.
Monitor for relapse signs during the 12 months following treatment completion.
Discuss thromboembolism prevention with your specialist vet from the outset of treatment.