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Overview

Between 2 and 3 percent of children younger than 3 are allergic to milk. Although experts once believed that the vast majority of them would outgrow this allergy by the time they turned 3, recent studies contradict this theory. In one study, fewer than 20 percent of children had outgrown their allergy by age 4. Still, about 80 percent of children are likely to outgrow their milk allergy before they are 16.

Milk Allergy Symptoms

  • Hives
  • Stomach upset
  • Vomiting
  • Bloody stools, especially in infants
  • Anaphylaxis, a rare, potentially life-threatening reaction that impairs breathing and can send the body into shock

For more information on milk allergy symptoms click here.

Milk Allergy Management and Treatment

  • Avoid milk, other dairy products, and products containing milk protein; read labels carefully.
  • Administer epinephrine (adrenaline) if symptoms become severe.

For more information on milk allergy management and treatment click here.

Symptoms

Milk is one of the most common food allergens. People with an allergy to cow’s milk may also be allergic to milk from other animals, including sheep and goats.

Within a short period of time after consuming milk or a milk protein, you may experience the following symptoms:

  • Hives
  • Stomach upset
  • Vomiting
  • Bloody stools, especially in infants
  • Anaphylaxis, a rare, potentially life-threatening reaction that impairs breathing and can send the body into shock

If you or your child experiences any of these symptoms, see an allergist.

Diagnosis

At your appointment, your allergist will take a detailed history, including asking what you ate, what symptoms you experienced, how long the symptoms lasted and what you did to alleviate them. The most common allergy tests are a skin-prick test or a blood test; both look for the presence of immunoglobulin E (IgE) antibodies, which develop when your body is exposed to a substance to which it is sensitive. These antibodies trigger the release of chemicals that cause allergic symptoms.

In the skin-prick test, a liquid containing milk or a milk protein extract is placed on your forearm or back. Your skin is pricked with a small, sterile probe, allowing the liquid to seep into your skin. If you develop a raised, reddish welt, typically within 15 to 20 minutes, that can indicate an allergy. In a blood test, a blood sample is tested for the presence of IgE antibodies. The results are reported as a numerical value.

Research suggests that some types of milk proteins (casein and two proteins found in whey, alpha-lactalbumin and beta-lactalbumin) are more likely to cause serious reactions. A newer type of blood test, known as a component test, can help the allergist determine your risk for a serious reaction by looking for allergies to those specific proteins.

Another test your allergist may order is an oral food challenge. Under medical supervision, you’ll eat small amounts of a substance containing milk or a milk powder to see if a reaction develops. Because of the possibility that a reaction could be severe, this test is conducted in your allergist’s office or at a food challenge center with emergency equipment and medication on hand.

Management and Treatment

Avoidance of milk or items containing milk products is the only way to manage a milk allergy. People who are allergic to milk and the parents of children who have this allergy must read ingredient labels very carefully.

Milk is one of eight allergens with specific labeling requirements under the Food Allergen Labeling and Consumer Protection Act of 2004. That law requires manufacturers of packaged food products sold in the U.S. and containing milk as an ingredient to include the presence of milk or milk products, in clear language, on the ingredient label.

There are two main types of milk protein — casein and whey. Casein, the “solid” part of milk, comprises about 80 percent of milk protein. Whey proteins, found in the liquid part of milk, make up the other 20 percent. Milk proteins are found in many foods, including all dairy products, and in many places where they might not be expected. For example, some canned tuna, sausage, meats and other nondairy products may contain casein. Beverage mixes and body-building and energy drinks commonly contain whey. Milk protein has also been found in some chewing gum.

Some companies may voluntarily include information that their food products “may contain traces of milk” or that they are manufactured in a facility that also processes milk, though such advisory statements are not required by law.

Allergies to food (including milk) are the most common causes of anaphylaxis, a potentially life-threatening allergic reaction. Symptoms include swelling of the airways, impairing the ability to breathe, and a sudden drop in blood pressure, causing dizziness and fainting. An allergist will advise patients with a food allergy to carry an auto-injector containing epinephrine (adrenaline), which is the only treatment for anaphylactic shock, and will teach the patient how to use it. If a child has the allergy, teachers and caregivers should be made aware of his or her condition as well.

Some people with this allergy can tolerate foods containing milk that has been extensively heated, such as a baked muffin. Still, people with an allergy to milk protein should consult an allergist before determining whether they should completely avoid milk and other dairy products.

Milk is a fairly easy ingredient to substitute in recipes. Most recipes calling for milk can be just as successful by substituting the equivalent in water, juice, or soy or rice milk. If your infant is allergic to milk, talk to your pediatrician about which formula to use. Often, an extensively hydrolyzed elemental formula or a casein-hydrolysate formula is recommended for milk allergy in infants, as the proteins in these formulas have been extensively broken down. Alternatively, your infant’s doctor may recommend a soy-based formula.

Milk Allergy or Lactose Intolerance?

Milk or dairy allergies and lactose intolerance are not related.

People with a milk or dairy allergy experience symptoms because their immune system reacts as though milk and other dairy products are a dangerous invader. This reaction can cause hives, an upset stomach, vomiting, bloody stools and even anaphylactic shock — a life-threatening allergic response.

Individuals who are lactose intolerant cannot digest the sugar in milk (lactose) because they have a deficiency of lactase, an enzyme produced by cells in the lining of the small intestine. Lactase is required to metabolize lactose. The lack of this enzyme — which sometimes can just be temporary, due to infection — causes symptoms such as abdominal gas, diarrhea or abdominal cramps.

If you suffer digestive problems after eating or drinking dairy products, try tracking your diet and noting how your body reacts to the items you consume. You may also try temporarily cutting dairy products — milk, cheese and yogurt, for example — from your diet and see if your symptoms improve. Report the results to your allergist, who can do testing — typically, skin testing — to confirm a diagnosis.

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