I'm a 69 yo woman. I imagine you have switched hair care to minimal ingredients and "natural". I can use Matrix brand and Dove soap without problems. I had rashes on arms, legs, and back for decades. Dermatologists would just say "its dry skin" and give me hydrocortisone cream. In my case, the eczema was due to gluten intolerance. Rashes went away 14 years ago, after the intolerance morphed into celiac. I have kept a food log since, and am also sensitive to a lot of chemicals (including hair and skin products), NSAIDs, some legumes, and dust and sap of some trees (woodturner). My diet is mostly FODMAP. For me, eating a bite of Uncle Dave's bread (gluten) would bloat me up like the Pillsbury Dough Boy, the skin rash would come back, as would problems with balance, sleep, GI, and other symptoms. Oatmeal would do the same because of cross contamination. Oats are gluten free, but have to be certified as such because of crop rotation and processing in same plant as wheat/rye/barley. Elimination diets are one way to see if your skin is affected by what you eat.