Why do I only SOMETIMES have allergic reactions?

The question has come up (thanks, Lara) of why people are allergic to some coconut sometimes, and not other times. Well, coconut allergies seem to be related to skin, in my unscientific opinion.

I've never had huge problems with coconut milk for some reason. I was able
to eat Indian and Thai food and the only problem I had was feeling a little
dizzy and having some phegm. I think that this is because it just slid
right down with soft food, unnoticed by my immune system once it got past my
mouth. If I can get coconut down my throat, it usually doesn't bother me.
My terrible reactions were if I ate something chewy or crunchy that even
gently scraped the inside of my mouth. Weird, huh. For example, I could
eat cool whip on pancakes just fine, but if I mixed it with crispy bacon, I
would end up taking benadryl as my throat closed up.

I used to eat macaroons with just a little congestion,
so I don't know what the deal is with dried coconut. But give me coconut
shrimp and I'm dying. Still, mysterious why it only happens sometimes. It
could have to do with stress levels and health or some thing. I need to go
see if there are any new books in the library, or find an allergist who has
explored these things as much as I'd like!