If children are allergic, they will often show the following symptoms: firstly, they will cause symptoms in the digestive tract, because most allergies in children start with digestive tract allergies, there will be slow weight gain, even diarrhea, blood in the stool and other symptoms, mostly caused by allergy to milk proteins, and they need to apply amino acid milk powder to children. Secondly, skin allergy symptoms are manifested, and children may develop hives and eczema. In addition, children with respiratory allergies may have itchy nose, sneezing, nasal congestion, or even bronchial asthma.