Patch test response to house dust mites is positive in children with atopic dermatitis and in their parents.

We studied the patch test response to Dermatophagoides pteronyssinus in 79 atopic children and in their parents. The atopic children were divided into 3 groups: 1) children with atopic dermatitis (group 1); 2) children who had suffered from atopic dermatitis but the disease was cured (group 2); and 3) atopic children with asthma and without atopic dermatitis (group 3). Our data show that a significantly higher proportion of children with atopic dermatitis (groups 1 and 2) have positive patch tests to Dermatophagoides pteronyssinus in comparison to atopic children without atopic dermatitis (group 3) and the controls (p < 0.001). In addition, we have shown that a positive patch test to Dermatophagoides pteronyssinus is significantly more common in parents of children with atopic dermatitis with respect to parents of children with asthma or parents of control children.

Natural history of IgE antibodies in children at risk for atopy.

BACKGROUND: The relationship between atopic diseases and high serum IgE levels has been emphasized since the mid-sixties, when IgE antibodies were discovered. A number of environmental factors, such as the type of feeding, passive smoking, viral infections, early mold, house dust mite and pet fur exposure modulate IgE synthesis and affect the development of atopic diseases. OBJECTIVE: The aim of the present study was to investigate the natural history of total and specific IgE antibodies in babies at risk for atopy, enrolled in a prospective study for the prevention of atopic disease, and follow-up from birth to 4 years of age. METHODS: One hundred seventy-four babies (90 boys and 84 girls) at risk for atopy were enrolled in this study. At the last follow-up the children had a median age of 52 months (range 43 to 74 months), dietary and environmental manipulations for the prevention of atopic diseases were recommended. All the infants were examined at the ages of 1, 3, 6, 9, and 12 months and twice each year subsequently when detailed histories were taken and signs and symptoms of atopic disease were sought. Total and specific IgE to cow milk, egg, soy, wheat, and Dermatophagoides pteronyssinus (Dpt) were measured at 6 and 12 months of life and then every year. RESULTS: During the first 24 months of life, the number of children with specific IgE to foods (n = 30) was significantly higher in comparison to the number of children with specific IgE to Dpt (n = 12) (P = .0006). Cow milk and egg were the most common offending foods. The number of children with IgE to cow milk (n = 14) was significantly higher than that with IgE to soy (n = 9) (P = .0011). Total serum IgE levels were significantly higher in the group of children who developed atopic disease in comparison with the group that did not (P < .01). CONCLUSION: Dietary and environmental measures may influence the IgE response in atopy-prone children, thus confirming the role of environmental factors in the modulation of the phenotypic expression of atopy.

Prevention of atopic diseases in high risk babies (long-term follow-up).

Several studies have demonstrated that dietary and environmental manipulations in the first months of life have a protective effect on the development of allergic diseases in babies "at risk" of atopy. We have prospectively followed up 174 "high risk" infants who underwent dietary and environmental manipulations, such as exclusive breast-feeding for the first 6 months of life, supplemented if necessary with soy-protein formula (Isomil, Abbott), delayed weaning beyond the 6th month of life, and rigorous environmental manipulations for the elimination of house-dust mite and passive smoking. The low prevalence of atopic disease (10%) and the trivial course of the allergic manifestations in this "at risk" population confirm the effectiveness of this preventive program. Moreover, this study demonstrates that the incidence of atopic dermatitis peaks at 6 months, and decreases until it disappears. Food allergy appears only at 6 months and may disappear later. The incidence of asthma peaks at 6 and 36 months and decreases at low levels in the intervals. Allergic rhinitis develops not sooner than 36 months.