Respiratory Symptoms Strongly Predict More Persistent Cow's Milk Allergy

Jennifer Reid Holman, MA

November 13, 2006

November 13, 2006 (Philadelphia) — Most young children who develop an allergy to cow's milk eventually "outgrow" it within a few years. Experiencing respiratory symptoms with the allergy, however — such as wheezing or runny nose — strongly predicts the likelihood that the allergy will persist considerably longer into childhood. That was the finding of a study presented here at the 52nd annual scientific meeting of the American College of Allergy, Asthma, and Immunology.

"We have known for a long time that food allergies can cause respiratory effects," said researcher Alessandro Fiochi, MD, from the University of Milan Medical School in Italy. "This is the first study that shows these symptoms can actually predict which children are most likely to have a longer-lasting problem with cow's milk allergy."

The study included 153 children with confirmed immunoglobulin E (IgE)–mediated cow's milk allergy. Most of these children exhibited skin reactions to milk, such as eczema and hives. About half had asthma/rhinitis symptoms. Fewer than 25% experienced immediate gastrointestinal effects or anaphylaxis after ingesting cow's milk. Many children experienced 2 of these symptoms.
The median age of these children when they presented for allergy testing was 16 months (range, 1-186 months), and each child was followed with periodic challenges for an average of 31 months.

The researchers gathered data on several potential risk factors, including presenting symptoms, duration of exclusive breast-feeding, age when symptoms started, age when cow's milk was introduced to child's diet, level of milk-specific antibodies (IgE) generated, sensitization to dermatophagoides and eggs, the allergen dose that elicited a positive challenge, and the use of formula after the allergy diagnosis.

More than half of the children experienced a natural and complete remission of their cow's milk allergy during the study (median allergy duration, 18 months). Respiratory symptoms were the single strongest predictor of which children had a long-lasting allergy. Median duration of cow's milk allergy in these children was 41 months.

Presenting with anaphylaxis after ingesting milk was also strongly associated with a longer time to remission. Other significant but less strong predictors were reaction to low doses of the allergen during diagnostic testing and higher levels of specific IgE antibodies to the milk challenges.

"Food allergy should always be suspected as a cause of asthma, particularly in infants," said Sami Bahna, MD, chief of allergy and immunology at Louisiana State University Health Sciences Center in Shreveport. "Pediatricians often recognize the link between gastrointestinal or skin manifestations of this allergy, but many are unaware of the link to asthma symptoms. In fact, although it's not frequent, asthma can be the only manifestation of a cow's milk allergy in some children."

The current data do not indicate how much longer on average children with airway symptoms tend to have a cow's milk allergy. "That's the focus of our ongoing research, and we'll be analyzing the factors associated with that resolution," Dr. Fiocchi told Medscape.

According to the National Institute of Allergy and Infection Diseases (NIAID), cow's milk allergy is particularly common in infants and young children, affecting between 2% and 3% of those in developed countries. Infants are thought to be particularly susceptible because their digestive and immune systems are immature. NIAID and the American Academy of Pediatrics recommend breast-feeding infants for the first 6 to 12 months of life to deter milk allergies during this time.

ACAAI 2006 Annual Meeting: Abstract 13. Presented November 12, 2006


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