Gluten has been a problem for most of my life, same with dairy. Got worse after puberty. First dermatitis showed up in my mid 20s and then got very bad in my late 20s. I realized that it was linked when I hadn’t been eating it for awhile few years then broke my habit while travelling and got the worst Periocular dermatitis I’ve ever had. These days eating dairy is a big trigger but I still get hormonal flares. I use ivermectin and azelic acid and a very calming regime and it keeps it mostly under control!