Study sheds light on course of cow's milk allergy

Skin & Allergy News, Jan, 2006 by Robert Finn

Half of the children who are allergic to cow's milk at the age of 7 months develop tolerance by 2 years of age, but the children who are IgE positive tend to remain allergic longer, according to a prospective study by Dr. Kristiina M. Saarinen of the University of Helsinki and colleagues.

In addition, by the age of 8.6 years, children with IgE-mediated cow's milk allergy (CMA) more frequently had asthma, rhinoconjunctivitis, atopic eczema, and sensitization to any allergen than did control subjects. The children were part of a population-based cohort of 6,209 term newborn infants collected in 1994 and 1995. CMA was confirmed by an elimination challenge test in 118 of these children (J. Allergy Clin. Immunol. 2005;116:869-75).

At an average age of 7 months, 75 (64%) of those children had IgE-positive CMA. But 12 months later, at a mean age of 1.6 years, 21 of the IgE-positive children had switched to become IgE negative, and 11 of the IgE-negative children had switched to become IgE positive.

Children in the IgE-positive group were significantly more likely to have urticaria, exanthema, or both, whereas children in the IgE-negative group more often had atopic eczema and diarrhea.

On continued follow-up, the investigators determined that all children in the IgE-negative group had developed tolerance to cow's milk by the age of 5 years, but only 74% of the IgE-positive children had developed tolerance by that age.

At the final follow-up, at a mean age of 8.6 years, 15% of the children in the IgE-positive group still had CMA.

A multivariate logistic regression analysis revealed that CMA was an independent risk factor for the development of other atopic diseases and sensitization to inhaled allergens.

BY ROBERT FINN

San Francisco Bureau