Skin Concern) What could be the cause of this hives?

I occasionally get hives for unknown reasons, and it is so frustrating because I have no idea why. It itches terribly, but if I scratch, it spreads. It doesn't last long; it usually flares up for a few hours to a day and then goes down. I really want to know the underlying cause. I thought it might be a food allergy, but since the flare-ups are quite erratic, I don't think that's the case either. It seems to get a little worse when I overeat. I do take allergy medication when it gets severe... Does anyone else have similar hives and know what kind of condition it might be? For reference, it doesn't seem to be related to temperature or seasonality. I'm fine all year round, but then it just pops up for a day or two, so I'm just so frustrated. Does anyone know the reason?