There are many types of eczema and not all are driven by allergy. In children especially there is often confusion between Atopic (suggesting an allergic background) Eczema and Seborrhoeic (non-allergic) Eczema.
Very often parents subject their children to unnecessarily restrictive diets based on mistaken observation of what they think made their child’s eczema worse.
Stop guessing: find out with a formal, structured allergy test. With an increasing number of children with Atopic Eczema suffering also from dangerous food allergy it’s better you find that out in the doctor’s office than in A&E and in a crisis state.