[Prognoses of food allergy in infancy]

Food allergy as one of social health problems has gained more attention of people. However, few reports on prognosis of food allergy, the relation between infant food allergy and other allergic diseases, and factors affecting prognoses of infant food allergy in China. The present study was designed to investigate the evolution of infancy food allergy and to explore predicting factors of the tolerance to these foods and factors of other allergic diseases to provide a clue for managing children with food allergy reasonably and to improve their prognoses.

Totally 119 children with food allergy during infancy, who were diagnosed in the Department of Primary Child Care, Children's Hospital, Chongqing University of Medical Sciences from January 2000 to June 2003, were studied retrospectively by analyzing the follow-up data before March 2004. The occurrence of food tolerance and other allergic diseases were counted. Kaplan-Meier methods were used to calculate the cumulative tolerance probability. And the predicting factors of persistent food allergy and influential factors of other allergic diseases were analyzed by unconditional Logistic regression models.

The cumulative tolerance probabilities of cow's milk and egg were 42% and 31% one year after diagnosis respectively, 63% and 62% 2 years later, 77% and 80% 3 years later, and 100% after 4 years. And the severity of skin prick test reactions to cow's milk and egg was the predicting factor for persisting hypersensitivity to cow's milk and egg (OR = 2.535, 95% CI: 1.159-5.543; OR = 2.654, 95% CI: 1.302-5.410, P < 0.05). Thirteen cases presented with hypersensitivity to other foods (15.6 +/- 6.1) months after the diagnosis was confirmed, and the risk factor was the long-lasting hypersensitivity to egg (OR = 6.109, 95% CI: 1.818-20.527, P < 0.05). After 4 cases and 15 cases were diagnosed as allergic rhinitis and asthma, respectively, (16.8 +/- 8.3) months after diagnoses and the risk factors were the long-lasting hypersensitivity to egg and the respiratory symptoms (OR = 3.596, 95% CI: 1.429-9.045; OR = 4.235, 95% CI: 1.152-15.563, P < 0.05).

At least 75% of children with egg or cow's milk allergy could develop tolerance to egg or cow's milk within 3 years after diagnoses; 10.9%, 12.6% and 3.4% of children with food allergy suffered from other food allergy, asthma and allergic rhinitis. Strengthening the screening and management of children at high risk for persistent food allergy will contribute to improvement of the prognoses of food allergy.