Babies should not eat egg custard when they have a cold or fever because their digestive function is relatively poor, their absorption is poor and their appetite is relatively low. This is because egg custard may not be easily digested and contains more fat. Giving your baby egg custard at this time may cause digestive symptoms such as nausea, vomiting and diarrhea. Babies are more prone to allergies than usual during colds and fevers, and egg custard contains the most common allergens for babies, which may cause egg allergy symptoms. For example, digestive symptoms may worsen, skin allergies may appear, and in severe cases, coughing and shortness of breath may occur.