Common signs and symptoms of milk allergy can include:

• Mild wheezing or coughing;
• Vomiting;
• Skin rashes/hives;
• Digestive symptoms (e.g. stomach pain, diarrhea, nausea);
• Bloody stools (especially in infants).

Infants and children who are allergic to milk are more likely to have eczema (atopic dermatitis) and other allergies.

Milk allergy reactions can vary from localized reactions, such as a rash, to systemic reactions, including anaphylaxis. These reactions depend on which milk protein is causing the reaction. Milk comprises different proteins; a person with a milk allergy could be reacting to one of these proteins.

Specific IgE blood testing for milk components helps your healthcare provider identify the specific proteins that may cause your reactions. So instead of knowing that you're allergic to milk in general, you can know exactly which protein may trigger the reaction and the likelihood of outgrowing the allergy. Testing with allergen components can also be used to determine whether the allergy is to a protein that can be broken down when exposed to extensive heat, such as in cheese pizza or cookies. And component testing can help your healthcare provider determine whether an oral food challenge (OFC) test is recommended. An OFC test can be used to help confirm your milk allergy or to determine whether you have outgrown it.