AIHA Destruction of Red Blood Cell: Hemolysis
Primary AIHA is considered idiopathic when the actual trigger(s) are unknown.
Secondary AIHA is an autoimmune response to one or several different known triggers. These can include tick disease, vaccine reactions, infections, certain drugs, tumors, and even allergic reactions such as bee stings or snake bites.
The term IMHA is the accepted modern term when these triggers are identified.
Professionals will still use these terms interchangeably.