Does anyone have any experience with allergies and their LO?

How old were they when you suspected allergies or doctor suggested them?

Were they tested? What were/are they allergic to?

I don't even want to accept the thought as obviously I'm thinking about our dog, LO is 8w. See doctor tomorrow, was at the walk-in Thursday with LO and what he prescribed did nothing. The itching she does makes my heart hurt, she's stuffed up on/off with no other cold symptoms, no fever. Could it be something she's consuming via me (EBF?) Could be the Christmas Tree?