My first thought is a probiotic for intestines, also heralded as the most promising treatment for acne. Also very good for immunity. "Make sure that any supplement you select contains both Lactobacillus Acidophilus (L. Acidophilus) and Lactobacillus Bifidobacterium (L. Bifidobacterium)."

Iodine intake for thyroid (immune) function and selenium to increase it's effectiveness. 2 tsp of dulse or nori flakes, or a supplement. 1 brazil nut is all you need for selenium, or oatmeal. However the carbs in oatmeal could spike insulin which can be bad for some with SD.

Food for kidney health, cauliflower, blueberries, red grapes, garlic, olive oil, cabbage, bell peppers, onions, pineapple, etc.

Lastly repairing the skin barrier, I'm still figuring out how this is done exactly.

Not exhaustive list for treatments for SD but relevant to the comment.