The most important allergens in cow’s milk are whey and casein proteins. There is cross-reactivity between milk antigens of different species of mammals, the most homologous being milk proteins of cows, sheep and goats. Milk protein allergy may present with the following symptoms: itching of the oral mucosa, edema of the lips and tongue, tightness in the throat; nausea, vomiting, abdominal cramps, diarrhea, sometimes with bloody stools; urticaria, generalized maculopapular rash, skin flushing and angioedema; itchy nose, nasal congestion, runny nose, sneezing. Treatment of milk protein allergy: The key principle of treatment is to limit milk protein in the diet. Replacement formulas are not necessary for human milk-fed infants, and for children over 2 years of age who develop cow’s milk protein allergy. When milk protein allergy occurs in human milk-fed infants, the mother avoids milk products and can continue human milk feeding, but calcium supplementation is required. For non-human milk fed infants, alternative formulas include deeply hydrolyzed milk formula, soy formula, soy and rice hydrolysate formula and amino acid formula. In the face of so many formulas, how should I choose to use them? The following principles can be followed: 1. For those with severe allergies, amino acid formulas are preferred; 2. For those with mild allergies, it is recommended to use deeply hydrolyzed milk formulas first; (because amino acid formulas are more expensive and taste worse, if price and taste are not a problem, it is better to apply amino acid formulas) 3. hydrolyzed milk formula is better than deeply hydrolyzed rice formula; 5. If for special reasons hypoallergenic formula cannot be used, other milk sources can be considered. However, goat, sheep and buffalo milk should not be used to treat cow’s milk protein allergy because it may lead to severe allergic reactions. Camel milk can be used as a substitute for children after 2 years of age, and horse milk can be used for children with delayed reactions to cow’s milk protein allergy. Duration of treatment: at least 3 to 6 months, with re-evaluation every 3 to 6 months recommended to adjust the duration of avoidance dietary treatment. Infants with mild milk allergy (mainly mild eczema): long-term use of amino acid formulas and deeply hydrolyzed protein formulas is generally not recommended. Try adding moderately hydrolyzed protein formula after 1 to 3 months of using amino acid formula and deeply hydrolyzed protein formula, and continue to use it if they can adapt; if they cannot adapt, they should try adding moderately hydrolyzed protein formula again after 1 to 2 years. You can also try moderate hydrolyzed protein formula directly.