Your dog’s immune system is key to fighting infections and keeping her healthy. But sometimes the immune system goes awry and starts attacking what it’s meant to protect. And that can have drastic consequences.

In cases of immune-mediated hemolytic anemia — or IMHA [pronounced by saying each letter]— a dog’s body destroys its own red blood cells. And sometimes other blood cells, such as platelets — which control bleeding —become collateral damage.

As a result, dogs with IMHA have too few red blood cells — that is, they’re anemic. Red blood cells carry oxygen to the body. That provides energy and gives gums their pink color. So anemic dogs can have pale lips and gums and may seem tired for no apparent reason.

If the problem isn’t treated, dogs with IMHA can die. So keep tabs on your pooch’s pep and pink gums. They can provide important clues to a bigger story.