"Just cut out dairy" or "try going gluten-free" is some of the most common advice people with eczema hear, often from well-meaning strangers online. The truth is messier: some people do notice a real link between certain foods and their skin, and plenty of others don't notice anything at all. Cutting out whole food groups on a guess is a big ask, so it's worth actually tracking first.
A flare doesn't usually show up the same hour you eat something, it can take anywhere from a few hours to a couple of days. That gap makes it almost impossible to trust memory alone, by the time your skin reacts, the meal that might be connected to it is long forgotten.
If a suspected food only shows up once before a flare, that's not enough to call it a trigger, it could easily be something else entirely. Comparing several days you ate it against several days you didn't, over a few weeks, is what actually starts to reveal a real pattern instead of a coincidence.
This is general, practical information, not a diagnosis or treatment recommendation. Cutting out food groups, especially for a child, is worth doing with a doctor or dietitian involved, not based on a hunch alone.
This is exactly what I built SkinFam for, a private, on-device diary where you can log your day and your skin side by side, and look back over weeks to see what actually lines up. Nothing you log ever leaves your phone. Get SkinFam free on the App Store.