Cow milk allergies can affect people of any age, but it is more common among infants.  About 2 to 3 percent of infants have a cow milk allergy, which they typically outgrow.  Casein and whey, which are the main proteins in cow milk, can cause allergic reactions in infants with a genetic predisposition.  When these infants are exposed to cow milk, they can develop certain antibodies to casein, whey, or both, that trigger allergic reactions.  This can occur immediately or up to several days after drinking the milk.  Symptoms may include hives, eczema, facial swelling, vomiting, diarrhea, or wheezing.  Severe reactions rarely occur, but can result in shock.

Lactose intolerance is a different form of cow milk allergy and is rare in infants.  It is more common among older children and adults.  Lactose intolerance does not involve our immune system, but is rather due to lack of the specific enzyme to digest the sugar lactose.  Small amounts of cow milk are usually tolerated.  Except for skin rash and wheezing, other symptoms are similar to cow milk allergy, including diarrhea, vomiting, and abdominal pain.

If your infant is allergic to cow milk, goat milk is not a good alternative since it contains proteins similar to cow milk.  You may be advised to switch to a soy-based formula.  Because it has no milk sugar (lactose), soy is also used by people who are lactose intolerant.  Unfortunately, around twenty percent of children allergic to cow milk are also allergic to soy milk.

If your infant can’t tolerate soy, you may have to switch to a hypoallergenic formula.  These formulas contain cow-milk proteins that are broken down into small particles so they are less allergenic than whole proteins in regular formulas.  Most infants who have a milk allergy can tolerate these formulas, but in some cases, they still provoke allergic reactions.  In these cases, amino acid based infant formulas containing protein in its simplest form is recommended.  Partially hydrolyzed formulas, not considered truly hypoallergenic, are not recommended for infants allergic to cow milk.

Breast milk is the best form of nutrition for infants.  The American Academy of Pediatrics recommends breastfeeding for at least six months if possible.   However, these is no conclusive evidence breastfeeding can prevent allergies from developing later in your child’s life, but it does delay the development of food allergies by postponing your infant’s exposure to those foods that have the potential to cause allergies.