3. Vinegar
Most condiments, including the likes of salad dressings, ketchup, and mayonnaise contain vinegar. Vinegar is also used on its own, either as a flavoring on top of fries or as a dipping sauce for Italian dishes. The problem with vinegar for sufferers of this particular skin condition is that it is extremely concentrated in terms of its yeast-like byproducts and toxins.
It could be a difficult element to completely remove from any diet, given that many restaurants and cafes serve dishes with a sauce as standard, however trying your best to limit it could help in calming the skin condition down. Barley malt, also, should be avoided, and its presence in foods such as cereals, crackers, and bread means that it is a far more common ingredient than most might think. Either way, vinegar, and barley malt both promote yeast growth, so get them out of there. Entirely if at all possible.