How can you tell if my eczema is from a food allergy?

Timing and testing: About 33% of people with moderate to severe eczema have an allergic trigger. The allergic trigger could be a food or dust mite. Sometimes the pattern of eating the food followed by flaring of the eczema will help, but the best test is to eliminate the food and monitor to see if the eczema improves. To determine which foods to eliminate, allergy blood or skin tests can be helpful, but not perfect.