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Milk Allergy

What is a Milk Allergy

Milk allergy or milk protein intolerance is a hypersensitivity reaction to protein in cow’s milk, occurring in 2-3 % of infants and toddlers. It is usually first seen in infants under the age of 3 months, although if cow’s milk is not introduced until later in infancy, it will show up later. It mainly affects the intestinal tract, and comes to parents’ attention when they note streaks or flecks of blood in their baby’s stool. The stool may also be a little loose. Less commonly, the initial signs and symptoms of cow’s milk allergy will include vomiting, diarrhea, anemia, and poor growth. If a child is breastfed they can still have hypersensitivity if their mother’s diet is rich in cow’s milk products. Approximately 30% of infants with sensitivity to cow’s milk also have sensitivity to soy, in which case the infant and/or mother will also need to avoid soy products.

Basically, the sensitivity is a reaction to the protein in the milk, not the sugar. The sugar in milk is called lactose and the enzyme that breaks it down is lactase. Congenital lactase deficiency (commonly referred to as lactose intolerance) is rare, and is not considered a food allergy but rather a food intolerance.

Food allergies occur in about 6% of children under the age of 3 years. Ninety percent of these allergies are reactions to egg, milk, peanuts, tree nuts, soy, wheat, and fish. The majority of these children react to a only a single food.


Cow’s milk protein intolerance affects mainly the intestinal tract. In the vast majority of cases, the symptoms will be related to the intestinal tract and include blood streaks with mucus in the stool in an otherwise healthy infant. If limited to these symptoms it is reasonable to make a presumptive diagnosis if cow’s milk allergy. In a thriving infant or child with these limited intestinal symptoms, it is also reasonable to first give a trial off cow’s milk based products before performing any further testing, and to follow the child with serial testing of the stool for blood in the doctor’s office. The stool should be free of blood by 2 weeks on an avoidance diet, if not, consult your physician.

A severe form of an allergic reaction to food, called anaphylaxis, can occur with milk but is uncommon. Anaphylaxis to foods is actually the least common form of food allergy. When it occurs, it occurs most commonly with peanuts. Other manifestations of food allergy include hives, lip and throat swelling, and wheezing.

The gold standard for diagnosing food allergies today is a double-blind placebo-controlled food challenge. This basically means that the infant or child is given a small amount of the suspected food in a controlled setting such as a doctor’s office, and neither the physician nor the patient/family knows whether the food is the suspected food or a placebo such as sugar.

There are also skin tests and blood tests that can be done. One blood test in particular, the RAST, is best for those with the anaphylactic type of reaction. It is less accurate for those with respiratory symptoms of wheezing or hives, and even less accurate for those with only intestinal symptoms. Skin tests are positive in only 40% of children with cow’s milk allergy, thus missing 60%, and are only useful in patients older than 3 years.

Milk Allergy Treatment

The treatment is strict dietary elimination of cow’s milk products from the diet of the baby and/or mother. It is important for breast feeding mothers to remember that you don’t need to drink milk to make milk Your pediatrician may choose to try your infant on a soy formula first. The best way then to follow your infant would be to check the stools for visible blood and your pediatrician can check the stool for occult (invisible) blood by a simple test done on the stool in the doctor’s office. Approximately 30% of infants with cow’s milk protein intolerance have an intolerance to soy protein. If the blood in the stool continues, the formula should be switched to a casein hydrolysate formula (e.g., Alimentum, Pregestimil, and Nutramigen). The proteins in these formulas have been predigested. Note that goat’s milk and sheep’s milk should also be avoided because they are poor sources of folic acid, vitamin B12 and vitamin B6.

If there is a history of an anaphylactic reaction (airway constriction and shock) to milk, then in addition to a strict elimination diet, it is absolutely necessary to have a home injectable type of epinephrine: EpiPen. EpiPen comes in junior strength for children 5 years and under, and regular strength for over 5 years. The EpiPen looks like a pen, and is placed against the thigh for the injection. It is important that children with a history of anaphylactic reactions to foods also have an EpiPen at school.

Important points

The majority of children with an allergy to milk protein will “outgrow” this allergy by 2 to 3 years of age. This is also true for allergy to eggs, but is not true for allergy to peanuts, tree nuts (pecans, almonds, Brazil nuts, cashews, filberts, pistachios, walnuts), fish, shellfish, and seeds (caraway and sesame).

If you are following an avoidance diet, you must get into the habit of reading the ingredients list on the foods you buy. Look for : milk solids, powdered milk, condensed milk, evaporated milk, milk chocolate, ice cream, cottage cheese, cream, butter, butter milk, cheese, yogurt, margarine, whey, curds, casein, sodium caseinate and calcium caseinate. As stated above, goat’s milk and sheep’s milk should also be avoided.

If you are a breastfeeding mother and have been placed on a milk-free diet, you should eat calcium rich foods or take calcium supplements for a total of 1300 mg of calcium per day.

Infants needing a milk-free diet and placed on one of the specialized formulas will be getting enough calcium and other nutrients until the age of 1. After 1 year, most children are started on whole milk. Children with cow’s milk allergy may still need to avoid milk products until age 2 or 3 years and therefore will need to get adequate calcium. Recent studies have also targeted concern over inadequate vitamin D and riboflavin in a milk-restricted diet.

The recommended daily amount of calcium for children ages 1 to 3 years is 500 mg. Below is a list of non-milk and non-soy calcium containing foods

Non-Milk and Non-Soy Calcium Rich foods

  • calcium fortified orange juice – 300 mg per 8 ounces
  • fortified rice milk – 300 mg per 8 ounces
  • canned sardines – 370 mg per 3 ounces
  • canned salmon – 160 mg per 3 ounces
  • cooked broccoli – 68 mg per ½ cup
  • 10 dried figs – 269 mg
  • cooked collard greens -350 mg per 1 cup
  • cooked spinach- 250 mg per 1 cup

You may find many of the foods on the above list difficult to feed to your 1 year old.

You may need to give a daily multivitamin supplement (liquid or chewable) with calcium, vitamin D and riboflavin if you feel your child’s diet is not adequate. Making an appointment with a nutritionist to go over the specifics of your child’s diet may be helpful.

What about fat in the diet of children under the age of 2 years with cow’s milk allergy?

Fat is important for energy requirements and nervous system growth and development. It is for this reason that the recommended percent of calories from fat in this age group is 50%. Parents of children with cow’s milk allergy need to be aware of this because many children this age get their fat from milk and milk products. Non-milk sources of fat include nuts, legumes like peanuts or peanut butter, eggs, meats, fatty fish such as salmon, vegetable oils and mayonnaise.