Immune mediated haemolytic anaemia (IMHA) in dogs

dog on white background


  • Immune mediated haemolytic anaemia (IMHA) is a condition that causes the body to destroy its own red blood cells.
  • IMHA causes severe anaemia, which often leads to low energy, pale gums, breathing problems, collapse and sometimes death.
  • IMHA is an extremely serious condition but fortunately, most dogs recover if they are treated quickly.

General information

‘Autoimmune’ or ‘immune mediated’ conditions are caused by a fault in the immune system that causes the body to attack and destroy normal, healthy body cells.

Immune mediated haemolytic anaemia (IMHA) is an autoimmune condition that causes the body to destroy its own red blood cells. These red blood cells are essential because they carry oxygen round the body. IMHA is very serious, often leads to severe anaemia, and can be fatal if left untreated.

Some dog’s develop IMHA slowly and have vague symptoms that get worse over time, but in most cases, IMHA develops rapidly and causes symptoms very suddenly. IMHA can affect any dog, at any time but appears to be most common in middle age dogs, especially in certain breeds such as cocker spaniels.


Photo of pale gums in a dog

Pale gums in a dog

When to contact your vet

IMHA is a very serious disease that needs intensive, emergency treatment form a vet. If you suspect your dog might be developing IMHA, contact your vet immediately for an emergency appointment.

Diagnosis and treatment

To diagnose IMHA, your vet will need to examine your dog and run some blood tests to see if they are anaemic (low in red blood cells). If your dog has IMHA, they will need treatment to stabilise them and stop their red blood cells from being destroyed. It’s likely that your dog will need to stay in the veterinary hospital for intensive care until they have started to recover. Treatment for IMHA often includes:

  • Steroids and other immunosuppressant drugs – to stop the body attacking its own red blood cells and allow it to replace the cells it's already destroyed.
  • Blood transfusion – if your dog is severely anaemic, they might need a blood transfusion to save their life.
  • A fluid drip – to keep your dog hydrated, and protect their organs while they recover.
  • Oxygen – if your dog is severely anaemic, oxygen might be necessary to help their remaining blood cells carry as much as possible around the body.

Ongoing care at home

Once your dog has started to improve, they will be sent home to continue recovering. You will need to give them their medication, keep a close eye on them and make sure they continue to eat and drink.

  • Medication – It's very important you give your dog's medication at the correct dose and time. It's likely they will need to stay on treatment for several months and that the doses will change as they get better. You may find our medication planner useful.
  • Food and drink - initially you may need to tempt your dog to eat by warming their food and/or hand feeding them. If your dog stops eating or drinking, contact your vet straight away.
  • Bedding - your dog will need a warm, comfortable and quiet place to rest and recover.
  • Exercise - it’s fine for your dog to have a little wander around the house and garden but shouldn’t do any strenuous exercise, or be taken on walks until fully recovered.


The outlook for most dogs with IMHA is good. Even if they are very poorly, most get better with intensive veterinary care and treatment. However, there is are some cases where sadly a dog won’t respond to treatment or becomes so poorly that they don’t survive IMHA.  

IMHA can come back so if your dog has had IMHA previously, keep an eye out for symptoms of it returning.


Treatment for IMHA can be very expensive because it requires such rapid and intensive treatment. It’s important to speak openly to your vet about your finances, the cost of treatment, as well as what you think is right for your dog. There might be more than one treatment option, so if one doesn’t work for you and your dog then your vet may be able to offer another.

Consider insuring your dog as soon as you get them, before any signs of illness start. This will ensure you have all the support you need to care for them.

Published: August 2020

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Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst