Especially milk and milk products.
If you decide to try this, don't do it halfway. Read the ingredients of everything you eat. Don't eat at restaurants. Stick with it for three months.
I went from having difficulty walking, and being unable to use my hands due to severe dishydrotic eczema, to being completely 100% healed.
This was after I was diagnosed with shingles, given a ton of very harmful steroids and steroid creams, told by multiple doctors and dermatologists that it was an incurable autoimmune condition that I'd be living with forever.
I was also told explicitly by one dermatologist that it was impossible that my problems were caused by a food allergy, that any results I was seeing were coincidence.
It turned out, I'm allergic to milk protein.
If you're battling this as well, it might be worth your time to look into elimination diets.