According to the Food Allergy and Anaphylaxis Network, milk is one of the most common allergens for children under age three. Most infants who are allergic to milk exhibit symptoms early, during their first year, and many outgrow it. A milk allergy is different from lactose intolerance; allergies involve a reaction of the infant's immune system, while intolerance involves the digestive system. A rash is one possible indication that your infant is allergic to milk.
Types of Milk Allergy Rashes
Many different types of rashes could indicate that your infant is allergic to milk. Any allergic reaction to food can give your infant a rash. Some of the common type of rashes caused by milk allergies are acne, hives and eczema, all of which can appear on any part of your infant's body. Rashes caused by a milk allergy may also be concentrated around your baby's mouth. A milk allergy can also create a red ring rash around your infant's anus, often accompanied by a diaper rash.
Distinguishing Milk Rash from Others
A milk allergy rash usually appears shortly after your infant is exposed to milk, often within a few hours. If your infant is having an allergic reaction, he will often have other symptoms such as diarrhea, vomiting, runny nose, irritability, difficulty breathing and swelling. If your baby is breastfed and allergic to cow dairy in breast milk, he will probably have a reaction within 2 to to 24 hours after the mother is exposed to dairy.
The best way to treat a milk allergy rash is to eliminate the infant's exposure to dairy. You can do this with an elimination diet, in which you remove all sources of dairy from the baby's diet. Remove dairy from your infant's diet for at least two to three weeks, and watch to see if symptoms improve. If you are breastfeeding and suspect that the rash is caused by cow protein in your breastmilk, it may take as long as four weeks for all the dairy to get out of your infant's system and for symptoms to completely disappear.
Other Common Rashes in Infants
If eliminating all dairy from your infant's diet does not clear up his rash, then consider other causes for your baby's rash. Other common types of rash in infants include contact rash, yeast rash and impetigo. If your baby's rash seems to be an allergic reaction but eliminating milk does not cause it to improve, then consider other possible food allergies as the cause.