Though many children may never have allergies and those that do might have such mild reactions that they are missed completely and disappear, some children are more susceptible than others. Allergies in children can affect varied age groups in different ways. Younger children and infants might get eczema or develop asthma during their early years. Some will grow out of these and some will go from one allergy to another, known in the medical world as a progressive allergy disease or atopic march. Generally most childhood allergies manifest themselves in about ten to twenty percent of kids, usually seen in their early infancy as eczema, itchy rashes that develop on the cheeks, scalp, legs, arms and in creases all over the body.