Cow's milk is a primary source of dairy in the United States, and it is the No. 1 food allergy in infants, according to the United Kingdom Dairy Council. However, cow's milk is dissimilar from human milk in protein and fat. The protein casein, which is found in greater concentration in cow's milk than human milk, is the source of dairy allergy. When the body develops an allergic response to casein, side effects can range from mild to life-threatening.
Vomiting and Diarrhea
Especially in young children, the first sign of a dairy allergy usually occurs in the stomach and is related to digestion. Diarrhea may be frequent; stomach pain and nausea often accompany the loose stools. Vomiting is also likely and can occur repeatedly. Projectile vomiting, during which stomach contents are ejected forcefully, is also possible. Nausea, vomiting and diarrhea also can be the first indications of dairy allergy in adults.
Skin Reactions
In addition to stomach distress, allergic responses can activate histamine release and cause skin rashes, itchiness and hives. Redness, hives and rash can occur on the torso or the entire body after ingestion of dairy products. In highly sensitive individuals, hives or itch can develop simply from skin contact with a dairy product. Because this type of allergic reaction is directly related to histamine release by the body, an antihistamine like Benadryl may lessen the skin reactions. Any food allergy problem should be reported to and treated by a health care professional.
Breathing Problems
Wheezing, cough and itchy throat are respiratory problems associated with dairy allergy. These can occur directly after ingesting dairy products or when dairy proteins are inhaled during cooking. The most severe type of breathing problem that occurs from dairy is life-threatening anaphylaxis. Anaphylaxis is shock reaction by the body, during which breathing and blood pressure are severely altered. Anaphylaxis can occur within minutes of ingesting dairy in highly allergic individuals. It is treated with injected epinephrine and emergency medical care.
