When Might My Child Outgrow His Milk Allergy?

Cow's Milk Allergy - Understanding What it is and How Long it Lasts

If your child has an allergy to milk, you may have heard that many children outgrow these allergies. When does this occur? And, importantly, is your child truly allergic to milk in the first place?

Outgrowing a Food Allergy to Milk - How Common and What Age?

Cow’s milk allergy is the most common food allergy occurring in young children, affecting between 2 and 7.5% of kids under age one. Previous studies have shown that most children will outgrow milk allergy by three to five years of age. That means that a significant proportion of children will continue to be allergic to milk, at least until their adolescent or teenager years, and may never outgrow their milk allergy. More recent information suggests that the number of children who do not outgrow their milk allergy is even higher.

Is it Really a Milk Allergy?

Your pediatrician may mention the term "allergy" without offering clarification that may help you get a better handle on exactly what your child is facing.

True allergy - True allergy to milk involves the presence of allergic antibodies, or IgE, against various proteins in milk. The diagnosis is made with a positive allergy test to milk.

Non-allergic reactions to milk - But non-allergic reactions to milk can also occur in children. These are identified by the absence of allergic antibody and a negative allergy testing result. Non-allergic reactions to milk are broken down into two major types:

Diagnosing True Milk Allergy

The diagnosis of true milk allergy may include a combination of a careful history, physical examination, an elimination diet, skin prick tests, specific IgE measurement, and a food challenge test.

Unfortunately, the most sensitive and specific test for milk allergy is a challenge test, having your child drink milk. This involves starting with an elimination diet, followed by an oral food challenge. This is not recommended, however, for children who have had an anaphylactic reaction to cow's milk for obvious reasons.

Outgrowing True Milk Allergy

Studies over the past decade, in contrast to earlier studies, suggest that outgrowing milk allergy may not be as common as previously thought, and also occurs later in childhood than was expected.

A 2007 study found based on the most accurate definition of milk allergy found that the percentages of previously allergic children who could tolerate milk at various ages were:

  • 19% by age 4
  • 42% by age 8
  • 64% by age 12
  • 79% by age 16

Which Children are More Likely to Outgrow Their Food Allergy?

So how can you know if your child is likely to outgrow her allergy or not?

Part of the answer may depend on other allergies your child has. Studies show that children with allergic rhinitis (hayfever), asthma or other common food allergies are less likely to outgrow milk allergy. In addition, children with milk allergy who ever received baby formula during infancy were also less likely to outgrow milk allergy.

The most helpful predictor of outgrowing milk allergy in these studies was the level of allergic antibody to milk measured in the blood. This is determined by a radioallergosorbent test, RAST, with a level of around 2 kU/L (kilounits per liter) or less being most predictive of having outgrown milk allergy. Many allergists find that following the allergic RAST antibody level to milk is very helpful in determining when a child may have outgrown a milk allergy and when he may be ready for an oral food challenge under medical supervision. Other researchers have suggested that an end point prick test may also be used as a predictor of when to perform an oral food challenge.

As noted under diagnosis, the most sensitive test to determine if a milk allergy is present is not a blood test, but the reaction a child has upon being challenged with the offending food. Unfortunately, some children may never outgrow their milk allergy, and their food allergy may persist into adulthood, or even indefinitely.

Coping with Milk Allergy

It can be difficult to cope with a sensitivity to milk whether it represents a true food allergy, lactose intolerance, or other causes. Because milk products are a common ingredient in many packaged foods, cooking from scratch can be a relatively easy way to avoid hidden sources of milk. Here are some tips on foods and food products to avoid on a milk-free diet.

At the current time, the only treatment available for milk allergy is avoidance, though studies are looking at immunotherapy hoping for other treatments in the future.

Finally, if you or your child are coping with other food allergies as well, you may be wondering what to listen to. It seems that everywhere you turn you hear a different statement of fact about food allergies, and many of these contradict each other.

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