My daughter is extremely allergic to MSG, and many people who suffer from eczema actually are reacting to MSG that they eat in their foods. To eliminate it from the diet is tough, because like you say it is in just about everything. However, in recent years its been easier to find MSG free products.
Basically, your best bet if you want to avoid MSG is cook from scratch. And if you have questions regarding MSG possibly being in a product, call the customer service number listed on the item. Maybe if enough people call and complain that they can’t use a product because of MSG, the manufacturers will stop putting it in everything!!