Dermatologist said my triggers don’t cause my eczema flare up

So I went to the dermatologist today for my eczema. When explaining my experiences and thoughts on my eczema she told me that eczema just happens and it doesn’t have an external reason for it to flare up.

This confused me because I read a lot of stories about certain foods / environments / allergies that trigger eczema flare ups. My dermatologist said that people are just looking for a reason but those are not the reason eczema flares up. It kinda just happens and it means the eczema stability just has a dip.

I really still don’t fully understand it, since the two times eczema got this bad I was in environments that were unclean. I know allergies don’t always cause eczema but I find it hard to believe this happens without reason.

I wonder what your thoughts are on this. I’m still learning about how all this works and why it happens.