The red rash on the baby’s face, to determine whether it is due to milk powder allergy, first of all, can be analyzed according to the sequence of the onset of time, and secondly, can be tested for allergens. 1. Analyze the sequence of the onset of time. Skin rashes caused by milk powder, also known as atopic dermatitis, the prerequisite for its onset is contact with allergens, so when rashes appear after taking milk powder, the first thing you should consider is milk powder allergy. 2. Improve allergen testing. By perfecting the allergen test, the cause of the allergy can be clarified, in which it can be excluded whether it is allergic to milk powder or not, which is also the most direct and effective test method. If it is clear that you are allergic to milk powder, first of all, you should avoid taking milk powder again, and secondly, according to the severity of the allergy, you can choose the anti-allergy medication under the guidance of the doctor, such as oral loratadine tablets.