Clinical manifestations of milk protein allergy The clinical manifestations of milk protein allergy involve multiple organs and organs, mainly the skin, respiratory system, and digestive tract. It can be classified as mild to moderate or severe according to the severity. The skin manifestations are mainly atopic dermatitis, such as eczema, itching, rash, urticaria, edema, dryness, etc. In severe cases, children have exudative or severe atopic dermatitis; respiratory symptoms are generally asthma, cough, rhinitis, and in severe cases, acute laryngeal edema or bronchial obstruction with dyspnea; gastrointestinal manifestations are generally frequent reflux, vomiting, diarrhea, constipation, and iron deficiency due to occult blood or microscopic blood in stool. In case of iron deficiency anemia due to occult blood or microscopic blood in stool, severe ulcerative colitis can be diagnosed as severe manifestations. Some children may even develop acute allergy syndrome, which requires prompt hospitalization. Most infants have two or more of these symptoms at the same time, with vomiting and gastrointestinal symptoms appearing fastest, 1-2 hours after consumption of milk, and diarrhea appearing 2-6 hours after consumption. The incidence of atopic dermatitis in milk-allergic children under 1 year of age is 40-50%. Most children with persistent milk protein allergy have a family history of atopic disease and are intolerant to a variety of foods or have allergic diseases that can be altered by the consumption of milk protein. Most children with atopic dermatitis will develop rhinitis or asthma after the disease has resolved.