Methods: During the year of 2008 to 2010, 69 infants were diagnosed with food protein allergy (FPA) associated AD in Beijing Children’s Hospital through clinic. Follow-up of these subjects was performed in their pre-school ages. Medical histories related to allergies during toddler’s and pre-school ages were acquired through questionnaires. Serum specific IgE levels were tested for both food and aeroallergens. Skin prick test of aeroallergens was also performed.
Results：The overall follow-up rate was 79.71% (55/69). By pre-school years, these children’s prevalence of physician diagnosed AD after infancy was 41.82%, who were also identified as persistent AD. Prevalence of physician diagnosed AR and asthma were 32.73% and 10.91% respectively. Thirty two children accepted serum IgE level tests. Although all the subjects showed positive test results for food allergens in infancy, only 40.63% remained sensitized to food by pre-school years. Twenty six of the subjects had received screening test for aeroallergens in infancy and all proved negative results, but in pre-school follow-up, 71.88% of the followed subjects were sensitized to aeroallergens. Twenty nine children accepted skin prick test of inhalant allergens, of whom the positive rate was 82.76% (24/29). Respiratory allergic diseases were significantly more prevalent in children with intermediate to severe aeroallergen sensitization than others(P=0.027). Multivariable logistic regression analysis showed that persistent AD was an independent risk factor for airway allergies(OR=10.500, 95%CI: 2.670-41.292，P=0.001).
Conclusion：A considerable proportion (34.55%) of FPA associated AD infants develop AR or asthma by pre-school ages. Most of the food sensitized infants will outgrow it 4 or 5 years later, while tend to evolve to aeroallergens sensitization, usually from a negative result in infancy. By pre-school years, children with moderate to severe sensitization to aeroallergens are more vulnerable to respiratory allergic diseases than others. Persistent AD might be an independent risk factor for developing AR or asthma.