What causes fragrance reactions?

I get sneezy and my nose and eyes itch when using certain perfumes or skincare. But with perfume it only happens with scents with woody notes (my favorite types 😩). Does anyone know if there are particular ingredients I can watch out for? These days I mostly use fragrance free skincare and don’t wear perfumes at all. But just been wondering if I can still give some scents a try if I can tell what to skip just by looking at an ingredient list. Thank you 🙈