Have you ever encountered a skin allergy immediately after consuming milk or milk products? It could be due to casein present in the milk. Casein is a milk protein, usually found in cow’s milk or products made from it. A casein allergy test is essential to confirm the allergy because the allergic reactions are often confused with symptoms of lactose intolerance. While some symptoms may be similar, a milk protein allergy test using specific IgE testing distinguishes the condition. A casein allergy occurs when your immune system identifies casein as a harmful molecule entering the body. As a result, your body suffers from a severe immunological response to neutralise the milk protein. Apollo 24|7 has a dedicated milk protein allergy test to assist you in being aware of your condition. Below are the symptoms you can notice before going for a casein allergy test: Rashes on the skin Difficulty in breathing Severe pain in the stomach Digestive issues  Malabsorption of food Vomiting and diarrhoea Anaphylactic shock in severe cases Swelling on lips, tongue, throat, and face Nasal congestion Runny nose Itchiness in eyes  Continuous sneezing It is suitable to go for a milk allergy test for young children and infants because these allergies are common. Also, infants mostly rely on milk for their nutrition, so a casein allergy test is a precautionary step to avoid severe complications. Generally, breastfed infants are less likely to develop a casein allergy. Moreover, kids outgrow their milk allergy by the time they reach five years of age. In rare cases, children cannot do so and taking a milk protein allergy test can help manage the condition. People who are tested positive for a milk allergy test need to avoid the following food items: All forms of milk Butter and ghee Yogurt and curd Cheese and its derivatives Ice-creams Milk cream and its derivatives Custard and pudding  Any bakery item made of milk or its derivatives People with a family history of milk allergy are more likely to develop this condition. A casein allergy test is a simple blood test that hardly takes 5 minutes to complete the procedure. In this test, a specific IgE is tested, which acts against the milk protein and triggers a chain of reactions in the body. The technique used in the milk allergy test is known as flow cytometry analysis. This is a scientific technique to assess different parameters related to the cell using a cell sorting mechanism and to attach a fluorescent probe to the surface markers. A casein allergy test may also use the skin prick method to collect the blood sample. This simple technique uses an agglutination kit to test the presence of allergies. However, the flow cytometry is more accurate than the agglutination reaction in the milk protein allergy test.    Medically reviewed by Dr Jatin Ahuja, Infectious Diseases, Apollo Hospitals Indraprastha, South Delhi.