Questions submitted during the Underlying Disease Screening in Dogs with IMHA webinar related to IMHA triggers:
If my dog goes into remission, what can serve as a trigger for it to return?
Is pregnancy a trigger?
What % of patients develop IMHA secondary to a trigger like a tick bite?
Regarding: If my dog goes into remission, what can serve as a trigger for it to return?
There unfortunately is no way to know on a case by case basis at this time, except to say that if a trigger was identified in association with its development it should be avoided. Avoiding triggers such as Babesiosis that have a high level of evidence for causing IMHA in many patients would also be important. As mentioned in responses to the other questions, the evidence for trigger factors is summarized in a systematic way in the upcoming ACVIM Consensus statement on diagnosing and reviewing the evidence for trigger factors for IMHA. As mentioned above this will be available open access.
Regarding: Is pregnancy a trigger?
Pregnancy has been associated with IMHA in people. The mechanism is unknown.
Regarding: What % of patients develop IMHA secondary to a trigger like a tick bite?
There is evidence that the infections the ticks carry, particularly Babesia, can trigger IMHA as reviewed in the lecture and in the upcoming consensus statement mentioned above. To find out the prevalence of tick-borne disease in patients with IMHA compared to those with IMHA and no tick borne disease, we need to do controlled studies where all the patients are tested for infections in the same and comprehensive manner. This will likely vary with exposure risk and geographic locale. For example see Kidd L, Qurollo B, Lappin M. et al. Prevalence of vector-borne pathogens in southern California dogs with clinical and laboratory abnormalities consistent with immune-mediated disease. J Vet Intern Med 2017 29(3):908-16.
