Milk allergy can take years longer to outgrow

She had "sleepless nights in the beginning, but I was determined to let this child live his life," Cohen said.

Jeremy Cohen is allergic to all dairy products which means if he eats any food containing even a small amount of milk, cheese, or yogurt, he can become very ill.

"At the slightest consumption of dairy, I break out into hives, coughing and have to go to the hospital. ... It's a very, very severe reaction," Jeremy said in a telephone interview from the campus of Colgate University in Hamilton, New York, where he is a freshman.

His mother's fears have already been realized. Since he started school this fall, Jeremy has had one major allergic reaction that sent him to the hospital after eating at a restaurant. "All of a sudden I started feeling sick, coughing, turned bright red, and had hives all over." A policeman in the neighborhood drove him to a nearby hospital. Watch why milk allergies are more difficult to outgrow. »

A new study published in the November issue of the Journal of Allergy and Clinical Immunology suggests that 18-year-old Jeremy is not alone. The study showed that most children who had a milk allergy as infants did not outgrow the disease before entering elementary school, according to Dr. Robert Wood, chief of Pediatric Allergy and Immunology at the Johns Hopkins University School of Medicine in Baltimore, Maryland. Wood, one of the study's authors, said that finding was contrary to previous research.

For infants and young children, milk allergy is still the most common food allergy, affecting 2 percent to 3 percent of that population, the study noted.

Researchers found a "significantly different natural history of milk allergy than what had been reported in virtually all of the previous studies. ... They would have said that the vast majority of milk allergy is outgrown by age 3 and if not by 3 certainly by 5 or 6," Wood said.

According to the study, which examined children who had been sent by a doctor to a pediatric allergy center, "the prognosis for developing tolerance [to milk] is worse than previously estimated."

The study found that 19 percent of the group outgrew their allergy to milk by the age of 4; 42 percent by the age of 8; 64 percent by the age of 12. The study found that 79 percent of the group outgrew their allergy to milk by the age of 16, which means one in five did not outgrow the milk allergy by that age.

The authors said that the character of cow's milk allergy "has changed over time ... and may now truly be a more persistent disease."

"One of the huge frustrations for parents of milk-allergic children is that they will typically find that someone with peanut allergy gets lots of respect and lots of precautions taken and the same respect is almost impossible to get for milk allergy," Wood says. Examples of precautions are cleaning school lunch tables well or placing children with peanut butter at a separate table. "Whatever precautions need to be in place for something like peanut allergy, need to be in place for milk allergy as well," says Wood.

The study also found that even though many did not outgrow the allergy by age 3, some patients were able to outgrow it "well into adolescence," indicating that "there is no age at which outgrowing CMA (cow's milk allergy) is impossible."

When exposed to milk, children in the study had a range of reactions, including rashes, hives, gastrointestinal symptoms, respiratory difficulties and even multiple-organ anaphylactic shock, a severe, sometimes fatal reaction.

With data collected on 807 patients, this was the largest group of milk-allergic children ever studied.

Ninety-one percent of the children studied were allergic to at least one other food besides milk, suggesting this might be a particularly allergic group, especially since they had been referred to a pediatric allergy clinic.

The study found that kids who had asthma and hay fever were less likely to outgrow milk allergy. There was also a worse prognosis for those who had ever received infant formula.