Food allergies occur when the body treats harmless food as harmful compounds, producing antibodies called immunoglobin E (IgE) to fight them. Dairy and egg allergies are among the most common food allergies.
Symptoms of milk allergies include diarrhea, wheezing, projectile vomiting, rash and rhinitis (stuffy nose). Symptoms of egg allergies include hives, wheezing, aches and nausea.
In some cases, milk and egg allergies can cause anaphylaxis, where even a small amount of the allergen leads to a severe, full-body reaction. Anaphylaxis should be treated immediately with epinephrine and the allergic person brought to a hospital in case the reaction reoccurs.
Milk allergies are not the same thing as lactose intolerance, an inability to digest milk sugars (lactose), which causes diarrhea and bloating.
Because milk allergies are reactions to the proteins in milk, whey and casein, which are not broken down by heat, they can still be triggered if the milk is cooked.
Despite common beliefs that children outgrow allergies quickly, a study by the Johns Hopkins Children's Center found that many childhood allergies last into the school years and even beyond.