I have sensitivities that cause an eczema reaction on my face. Started nearly 10 years ago, right when I was super stressed with both work and moving house. The dry patches on my face have been there all this past year, but there have been times in the past, during the summer, when the reaction dies down and I can eat things I ordinarily avoid.
The list started with just cow milk and chicken eggs, but soon grew and appears to be still growing.
Definites: Cow dairy, eggs, anything mint, ginger, chocolate,
Highly suspect (some will be definite, but hard to isolate): sesame seeds, oregano, garlic, celery, tomato, rosemary, goat milk, sun flower seeds, coconut, vanilla, pepper (black, cayenne, and paprika).
My sensitivity to dairy was very high to begin with. I could tell within seconds that a flavoured chip/crisp used lactose as a carrier for the flavouring. Now a reaction might take hours or over night, or be cumulative over days, makes it very hard to pin point what specifically has caused the reaction.
Stress definitely makes it worse.
While there is certainly a popular view that such problems are the result of raising children in clinically clean conditions, I was not raised that way, more over, both my grandmother and grandfather, who grew up in 1920s rural Kentucky had a raft of sensitivities/allergies. Can't say for sure when they started, not as children, but certainly by the 1970s.